System of digital transmission, transmitter and receiver for this system, information carrier received using the transmitter in the form of a recording device

The subject of the invention is a method of transmitting and / or receiving a broadband digital signal, a transmission system and a receiving system for using this method, especially for

167 271 of a broadband digital signal with a specified sampling frequency, and especially a digital audio signal, through / from the transmission center.

In a known manner, the transmission of a broadband digital signal takes place in stages. In the first stage, a broadband digital signal is intended for transmission. Then the broadband digital signal is converted into a second digital signal, which contains successive frames, and each frame contains information packets. Each packet of information contains N bits, where N is greater than 1. In the next step, the third digital signal is fed to the transmission center.

The known method of receiving a broadband digital signal also takes place in stages. In the first stage, the third digital signal from the transmission center is accepted. In the second stage, the third digital signal is decoded into a second digital signal. In the next step, the second digital signal is converted to the original broadband digital signal.

The method of transmission of the type shown is known, for example, from MEKrasner's article entitled The Critical Band Coder - Digital Encoding of Speech signals based on the Percentual requirements of the Auditory System contained in Proc. IEEE ICASSP 80, volume 1, pages 327-331, April 9-11, 1980. This article deals with the method of transmission in which transmitter uses the subband coding system.

In the method known from said publication, the speech signal band is divided into a plurality of subbands whose width approximately corresponds to the critical bandwidth of the human ear in individual frequency ranges. This division was chosen because, based on psycho-acoustic experiments, it can be assumed that the quantization of interference in such subbands is optimally masked by signals in these subbands, if the quantification of the interference masking curve for the human ear is included in the quantization. This curve gives a threshold value for masking interference in the critical band by a single tone in the middle of the critical band.

In the case of high-quality digital music signal, which, according to the compact disc standard, is represented by 16 bits per signal sample for sampling frequency 1 / T = 44.1 kHz, it was found that with the right choice of bandwidth and the right choice of quantization for individual subbands, the use of this known subband coding system gives the quantized encoder output signals, which can be represented by an average number of about 2.5 bits per signal sample. The quality of the reproduced music signal is not noticeably different from the original music signal, in all channels, for all types of music signals.

The method of transmitting a wideband digital signal with a sampling frequency Fs, especially a digital audio signal, through a transmission center according to the invention, comprises the steps in which the wideband digital signal is received, the wideband digital signal is converted into a second digital signal containing successive frames. Each frame contains an IP information packet, each information packet contains N bits, and N is greater than 1. The second digital signal is then converted into a third digital signal, and a third digital signal is fed to the transmission center.

The method of reception according to the invention comprises the steps in which a third digital signal is received from a transmission center, a third signal is decoded and a second digital signal is obtained, a second digital signal is transformed and a broadband digital signal is reproduced.

The method of the invention is characterized in that the transmission method comprises additional steps in which the second digital signal is transmitted at an average frame rate of Fs / ns, the number of packets of information in the frames being taken equal to the value of P, or the first number is cyclically generated frames and a second number of frames, wherein the frames in the first number of frames contain the number P of information packets, and the frames in the second number of frames contain the number P + 1 information packets. Then, synchronization information is generated and the synchronization information is introduced into the first frame portion of the frame series. Where ns is the number of samples of the broadband digital signal that

167 271 corresponds to information associated with the second digital signal contained in one frame of the second digital signal.

In contrast, the receiving method comprises the steps of either receiving frames containing P information packets in each frame, if P is an integer, or receiving cyclically occurring frames with a first number of frames, containing the number P of information packets, and a second number of frames having the number P + 1 information packages.

The transmission method additionally comprises a step in which information regarding the number P is inserted into the first frame portion, the reception method further comprising the step in which information regarding the number P from the first frame portion is extracted.

The method of transmission includes additional steps in which system information is introduced into the first part of the frame and the signal information is entered into the second and third parts of the frame.

In contrast, the reception method includes additional steps in which system information is extracted from the first part of the frame and signal information from the second and third parts of the frame is extracted.

The system of the invention for transmitting a broadband digital signal includes an input terminal, a second digital signal generator circuit having an input connected to the input terminal and having an output, a third digital signal generator circuit having an input connected to the output of a second digital signal generator and having an output, and a transmission unit whose input is connected to the output of the third digital signal generator, and whose output is connected to a transmission center.

The system of the invention is characterized in that the second digital signal generator circuit includes a frame generator that includes a first frame generator assembly and a second frame generator assembly having outputs connected to the frame generator outputs. Furthermore, the system includes a synchronization information generator and a signal merging circuit, wherein the outputs of the frame generator and the synchronization information generator are connected to the corresponding inputs of the signal merging circuit.

An arrangement in which the second digital signal generator circuit comprises an encoder having a sub-signal separation assembly and a quantizer, wherein the sub-signal separation assembly has an input connected to the input of the second digital signal generator circuit, and the quantizer has an input connected to the output of the sub-signal separation assembly, characterized by that the system further includes an allocation information generator whose output is connected to the input of the signal bonding circuit.

A system in which the sub-signal separation assembly includes a subband separation and sampling frequency reduction assembly is characterized in that it further comprises a scale factor determination circuit whose output is connected to the corresponding input of the signal merging circuit.

An arrangement in which the subband signal separation assembly is a dual subband separation assembly and the quantizer is a dual signal quantizer is characterized in that the allocation information generator is a dual allocation information generator.

The scale factor determination circuit is the dual circuit for determining the scale factor.

The system according to the invention further includes an error correction encoder whose output is connected to the input of the signal bonding circuit. The frame generator includes an information packet generator.

The system according to the invention is preferably a registration system comprising a registration unit.

The wideband digital signal receiving circuit comprises a third signal receiving circuit, a third signal decoding circuit having an input connected to the output of the third signal receiving circuit and having an output, a reproduction circuit having an input connected to the output of the decoding circuit and an output terminal connected to the output of the reproduction circuit.

167 271

The system according to the invention is characterized in that the third signal circuit comprises a receiving unit P of frame packets and a receiving unit P + 1 frame packets. The reproduction circuit comprises a synchronization information detector whose input is connected to the input of the reproduction circuit.

The playback circuit includes a packet number detector whose input is connected to the playback circuit input.

The reproduction circuit preferably includes a system information detector and a signal information detector. The outputs of the system information detector and the signal information detector are connected to the playback circuit input.

The system of the invention comprising a decoder with a subassembly assembly is characterized in that the signal information detector includes an allocation information detector and a sample information detector, wherein the outputs of the allocation information detector and the sample information detector are connected to the decoder inputs.

The system according to the invention, in which the decoder comprises a synthesis filter, is characterized in that the reproduction circuit further comprises a scale factor information detector whose input is connected to the input of the reproduction circuit.

The system according to the invention is preferably a reproduction system comprising a reproduction assembly.

In the solution according to the invention, the division of frames into information packets ensures that for a wideband digital signal with any sampling frequency Fs, the average frame rate of the second digital signal transmitted by the transmitter is such that the duration of the frame in the second digital signal corresponds to the occupation time ns of the samples broadband signal. This enables synchronization based on the information packet, which is easier and more reliable than maintaining synchronization on a bit basis. In this way, when P is not an integer, the transmitter is able to provide a frame with P '+ 1 instead of P'blocks of information so that the average frame rate of the second digital signal frame can be maintained at Fs / n_s. Because in this case the interval between the synchronization information contained in the first part of the frame of the subsequent frames is also an integer multiplied by the length of the information packet, it is possible to maintain synchronization based on the information packet.

The first part of the frame may further contain system information. These may include the sampling frequency Fs of a wideband digital signal fed to the transmitter, copy protection characters, the type of wideband signal fed to the transmitter, preferably a stereo or mono audio signal, or a digital signal containing two independent audio signals.

Other system information is also possible.

The second and third parts of the frame contain an information signal. The transmitter contains an encoder that converts the broadband digital signal into a second digital signal in the form of a series of M sub-signals and ensures the quantization of individual components. For this purpose, any coding transformation is used, and preferably a fast Fourier FFT transformation. It is then necessary to use inverse coding transformation on the receiving side, preferably an inverse Fourier transform IFFT, to obtain a wideband digital signal.

The allocation information is inserted into the frame before the samples. The allocation information is necessary to ensure that the continuous serial bit stream of samples in the third part of the frame is split into individual samples of the correct number of bits on the receiving side. The allocation information may require that all samples be represented by a fixed number of bits per subband, per frame. It is also a transmitter based on a fixed or static allocation bit. The allocation information may also assume that the number of bits changes over a period of time appropriate for samples in the subband. Then we talk about a transmitter based on an adaptive system or dynamic allocation bit. Entering the allocation information into the frame before the samples is advantageous because on the receiving side it is easier to decode, with only a small time delay of the signal.

167 271

The third part of the frame contains information about the scale factors. They are associated with at least one quantized subband signal, contained in the third part of the frame, before the quantized subband signals. The samples can be encoded in the transmitter without their normalization, i.e. without dividing the amplitudes of the sample block in the subband by the amplitude of the sample having the highest amplitude in this block. . In this case, the scale factor is not transmitted. If samples are normalized during coding, scale factor information must be sent to ensure maximum amplitude measurement. If the scale factor information is also entered into the third part of the frame before the samples, then during the acceptance, the scale factors will be entered with the scale information and will be saved first in memory, and the samples will be multiplied immediately upon arrival, i.e. without delay, by inverse scale factor values. The scale factor information can be formed by the scale factors themselves. The scale factor as introduced into the third part of the frame is preferably the reciprocal of the maximum amplitude of the sample in the block, so that in the receiver it is not necessary to determine the inverse value, and consequently decoding is faster.

The receiving memory capacity is limited to the memory capacity needed to store system information, allocation information, and scale factor information.

The last, fourth part of the frame preferably contains information about error detection and / or error correction. After receiving this information in the receiver, it is possible to apply error correction arising in the second digital signal during transmission. The broadband digital signal may be a monaural signal. Alternatively, the broadband digital signal may be an acoustic stereo signal resulting from the left and right channel components.

The solution according to the invention can be used for digital transmission, especially for transmission of acoustic digital signals through the ether. Other applications are also possible. An example of this is transmission through optical or magnetic media. Transmission through optical media can be, for example, transmission via optical fiber, or via optical disks or tapes. Transmissions through magnetic media are possible, for example via a magnetic disk or magnetic tape. The second digital signal is then recorded in the format proposed in the present invention on one or more tracks of the recording medium, such as an optical or magnetic disk, or magnetic tape. The versatility of the solution according to the invention is due to the special format in which information in the form of a second digital signal is transmitted, e.g. via recording media. This is combined with a special transmitter design that is capable of producing this special format for various types of input signals. The transmitter generates the system information required for each signal type and inserts this information into the stream of transmitted data. On the receiving side, this is achieved through a special receiver that outputs system information from the data stream and uses it to correctly decode

The information packets then form a kind of simulated units that are used to determine the length of the frame. This means that they do not have to be clearly discernible in the information stream of the second digital signal.

The solution according to the invention will be explained on the basis of examples, with reference to the drawing in which Fig. 1 a shows a second digital signal formed by a transmitter composed of frames, Fig. 1b - a frame containing information packets, Fig. 1c - an information packet, Fig. .

- the structure of the frame, Fig. 3 - the structure of the first part of the frame, Fig. 4 - block diagram of the transmission system, Fig. 5 - example of the reproduction system, Fig. 6 - the transmitter in the form of the device recording the second digital signal on the magnetic recording medium, Fig. 7 - the receiver in the form of a device reproducing the second digital signal from the magnetic recording medium, Figs. 8a, 8b, 8c, 8d show further possibilities for the content of scale factors and samples in the third part of the frame, Fig. 9 shows another example of the transmitter, Fig. 10 - a second example of the structure of the first frame part, Fig. 11 - information in the first part of the frame of Fig. 10, more

167 271 in detail, Fig. 12 - frame structure filled with additional signals, Fig. 13a and Fig. 13b show the output of scale factors, Fig. 14 shows the quantization of scaled samples into the form of q - bit digital mappings, and Fig. 15 shows the decanting of the q - bit mappings digital.

Figure 1 schematically shows a second digital signal generated in a transmitter and transmitted through a transmission center. The second digital signal takes the form of a serial digital data stream and consists of frames. Two such frames, i.e., frame j and frame j + 1 are shown in Fig. La. Each j frame contains many IPI, IP2, IP3, ... information packets. Each information packet contains N bits bo, bt, b2, ... bN-i. The number of information packets in the frame depends on the bit rate of the BR bits at which the second digital signal is transmitted through the transmission center, the number of N bits in the information packet, where N is greater than 1, as well as the sampling frequency Fs of the broadband digital signal, and from the number of samples ns of a broadband digital signal whose information corresponds to this, and which after processing belong to the second digital signal and are contained in one frame.

The parameter P is calculated according to the following formula:

p BR n_s^{Ρ =} ΊΤ^ΧΞ

N Fs

If this calculation gives the integer P, then the number of information packets B in the frame will be equal to P. If the calculation does not give an integer, then several frames will contain P 'information packets, and other frames will contain P' + 1 information packets, where P 'is the next smaller integer after P. The number of frames containing P' with P '+ 1 packets of information is of course chosen in such a way that the average frame rate is Fn / ns. It was assumed that N = 32 and ns = 384.

Table 1 lists the number of information packets (slots) in one frame for these N and ns values ​​and for four BR bit rate values ​​and three Fs sample rate values. It is obvious that e.g. for a sampling frequency Fs of 44.1 kHz, the parameter P is not an integer in all cases and as a consequence the series of frames contains 34 information packets and the other frames contain 35 information packets, with BR equal to 128 kbit / s.

Figure 2 shows one frame containing P 'IPI, IP2, ... IPP' information packets. Sometimes a frame contains P '+ 1 information packets. This is achieved by extracting an additional information packet (empty slot) to the frame with P' information packets.

Table 1

<td>BR bit rate [kbits / s]</td><td>fs sampling frequency [kHz]</td><td>B number of slots in the frame</td>

<td> 128</td><td> 32</td><td> 48</td>

<td></td><td> 44.1</td><td>34 + filling</td>

<td></td><td> 48</td><td> 32</td>

<td> 192</td><td> 32</td><td> 72</td>

<td></td><td> 44.1</td><td>52 + filling</td>

<td></td><td> 48</td><td> 48</td>

<td> 256</td><td> 32</td><td> 96</td>

<td></td><td> 44.1</td><td>69 + filling</td>

<td></td><td> 48</td><td> 64</td>

<td> 384</td><td> 32</td><td> 144</td>

<td></td><td> 44.1</td><td>104 + filling</td>

<td></td><td> 48</td><td> 96</td>

167 271

Table 2

<td>Bit rate [kbit / s]</td><td>The total number of frames in the padding sequence</td><td>Number of frames with an empty slot</td>

<td> 128</td><td> 147</td><td> 122</td>

<td> 192</td><td> 49</td><td> 12</td>

<td> 256</td><td> 147</td><td> 97</td>

<td> 384</td><td> 49</td><td> 24</td>

The second column of Table 2 gives the number of frames in the fill sequence for a sampling frequency of 44.1 kHz and the four bit rates mentioned. The third column specifies these frames from the number of frames in the sequence in which they contain P '+ 1 information packets. By subtracting the numbers from the second and third columns from each other, the number of frames in the sequence containing P 'information packets is obtained. (P '+ 1) the information packet does not need to contain any information. (P '+ 1) the information packet may then contain, for example, only zero. It is obvious that the BR bit rate is not necessarily limited to four values ​​as given in Tables 1 and 2. Other, for example intermediate values, are also possible.

Figure 2 shows that the frame consists of three parts FD1, FD2 and FD3. The first part of the FD1 frame contains synchronization and system information. The second part of the FD2 frame contains allocation information. The third part of the FD3 frame contains samples and scale factors of the second digital signal.

Figure 4 schematically shows a second digital signal generator, hereinafter referred to as transmitter 1, having an input terminal 2 for receiving a broadband digital signal Sbb, which is preferably a digital audio signal. In the case of an audio signal, it can be a mono or stereo signal in which the digital signal contains the first (left channel) and the second (right channel) signal components. It is assumed that the transmitter includes an encoder for encoding the broadband digital signal subbands, and the receiver consistently includes a subband decoder for reproducing the broadband digital signal. Transmitter 1 includes a sub-signal separation assembly in the form of an analysis filter 3, responding to the broadband digital signal Sbb and producing a multitude of M subband signals Ssb1 to Ssbm ·. Analysis filter 3 divides the bandwidth of Sbb broadband signal with reduced sampling frequency into successive subbands having M numbers (1 &lt;m &lt;M), increasing with frequency. All these subbands may have the same bandwidth, or alternatively may have different bandwidths. In this case, the subbands may, for example, correspond to critical bandwidths of the human ear. Transmitter 1 also contains a quantizer 9, block by block, for individual subband signals.

The 6 subband encoder allows achieving a significant data reduction, for example from 16 bits per sample for a broadband digital Sbb signal, to 4 bits per sample in a signal, which is sent to a playback circuit hereinafter referred to as receiver 5, through transmission center 4 (Fig. 4) .

A ns of 384 is assumed. This means that there are blocks containing 384 samples of broadband digital signal, each sample 16 bits long. It was assumed that M = 32. Consequently, the broadband digital signal is divided into 32 subband signals in the analysis filter 3. 32 blocks from the subband signals appear on the 32 outputs of the analysis filter 3. Each block contains 12 samples, with the subbands having the same width, and each sample is 16 bits long. This means that at the outputs of the filter 3, the information content is still equal to the information content of the block with 384 samples of the Sbb signal at the input 2. Quantizers 9 provide data reduction through the use of jamming. The samples are arranged in 32 blocks from 12 samples, each block corresponding to one sub-band, and these samples are coarse quantized and can therefore be represented by a smaller number of bits. For the static allocation bit, all samples per subband and frame are expressed by a fixed number of bits. This number

167 271 may differ for two or more subbands, but may also be the same for subbands, for example equal to 4 bits. For the dynamic allocation bit, the number of bits selected for each subband can change over time, so that sometimes even greater data reduction or higher quality can be achieved with the same bit rate.

The subband signals quantized in the system 9 are fed to the encoder 6. Beginning with the quantization of the subband signals, the encoder 6 produces a second digital signal as illustrated in Figures 1 and 2. This second digital signal can be sent directly through the transmission center. However, it is more preferable to first adapt the second digital signal for transmission through the transmission center 4 in a signal converter that is not shown. Such a signal converter includes, for example, a known 8-by-10 converter. This converter shows 8-bit word data to 10-bit word data. In addition, it enables the use of interleaving. The purpose of processing is to be able to correct information errors received on the receiving side.

It is obvious that the signal received from the transmission center 4 by the receiver 5 should be de-interleaved and converted 10 to 8.

The layout and content of the frames will now be explained in more detail. The first part of the FD1 frame of Fig. 2 is shown in more detail in Fig. 3, which illustrates that the first part of the frame contains exactly 32 bits and is exactly equal to one information packet, i.e. the first IP1 information packet of the frame. The first 16 bits of the information packet create a synchronization signal (or synchronization word). The synchronization signal may contain, for example, only ones. Bits 16 to 31 represent system information. Bits 16 to 23 represent the number of information packets in the frame. This number corresponds to P ', both for the frame containing P' information packets and for frames containing the additional IP information packet P '+ 1. P' can be at most 254 (1111 1110 in binary notation) to avoid similarity to the synchronization signal. Bits 24 to 31 give information about the frame format.

Table 3 gives an example of the setting and meaning of this information. Bit 24 indicates the frame type. In the case of the A format, the second part of the frame has a different length (different number of information packets) than in the case of the B format. The second part of the FD2 frame in the A format contains 8 information packets, namely IP2 to IP9 information packets, and in the B format contains 4 information packets , namely IP2 to IP5 information packets. Bits 25 and 26 indicate whether copying of information is allowed. Bits 27 to 31 indicate the operating mode. This means a channel mode that indicates the type of broadband signal. It can be a stereo, mono or acoustic signal containing two different signal components, for example representing the same text, but in two different languages.

Table 4 shows the channel mode of operation. This illustrates how the signal components are divided between two channels - channel I and channel II, in the aforementioned cases.

Bits 27 to 31 also indicate the sampling frequency Fs of the broadband signal and the enhancement that can be applied to the broadband signal in the transmitter. The value of 50 gs, and 15 gs are the emphasis time constants and CCITT J. The value 17 indicates the specific emphasis standard defined by CCITT (Comite Consultative Internationale de Telegraphie et Telephonie).

167 271

Table 3

<td>Bit 24:</td><td>Frame Type</td><td> 0 1</td><td>Format A Format B</td>

<td>Bits 25</td><td>and 26: copyright</td><td> 0</td><td>0 without copyright, own entry</td>

1 no copyright, software

0 copyrights, own record

1 copyright, software

<td colspan="2">Bits 27 - 31: Mode</td><td rowspan="2">Częatotl.próbk.</td><td rowspan="2">EMPHASIS</td>

<td></td><td>display</td>

<td> 0 0 0</td><td>0 0 Stereo</td><td>48 kHz</td><td>without emphasis</td>

<td> 0 0 0</td><td>0 1 Stereo</td><td>48 kHz</td><td>50/15 usec</td>

<td> 0 0 0</td><td>1 0 Stereo</td><td>44.1 kHz</td><td>without emphasis</td>

<td> 0 0 0</td><td>1 I Stereo</td><td>44.1 kHz</td><td>50/15 psec</td>

<td> 0 0 1</td><td>0 0 Stereo</td><td>32 kHz</td><td>without emphasis</td>

<td> 0 0 1</td><td>0 1 Stereo</td><td>32 kHz</td><td>50/15 psec</td>

<td> 0 0 1</td><td> 1 0</td><td>reserve</td><td></td>

<td> 0 0 1</td><td>1 AND</td><td>reserve</td><td></td>

<td> 0 10</td><td>0 0 Channel 2</td><td>48 kHz</td><td>without emphasis</td>

<td> 0 10</td><td> 0 1 2</td><td>48 kHz</td><td>50/15 psec</td>

<td> 0 10</td><td>1 0 Channel 2</td><td>44.1 kHz</td><td>without emphasis</td>

<td> 0 10</td><td>1 I Channel 2</td><td>44.1 kHz</td><td>50/15 psec</td>

<td> 0 11</td><td>0 0 Channel 2</td><td>32 kHz</td><td>without emphasis</td>

<td> 0 11</td><td>0 1 Channel 2</td><td>32 kHz</td><td>50/15 psec</td>

<td> 0 11</td><td>And 0</td><td>reserve</td><td></td>

<td>0 1 AND</td><td> 1 1</td><td>reserve</td><td></td>

<td> 10 0</td><td>0 0 Channel 1</td><td>48 kHz</td><td>without emphasis</td>

<td> 10 0</td><td>0 1 Channel 1</td><td>48 kHz</td><td>50/15 psec</td>

<td> 10 0</td><td>1 0 Channel 1</td><td>44.1 kHz</td><td>without emphasis</td>

<td> 10 0</td><td>1 1 Channel 1</td><td>44.1 kHz</td><td>50/15 psec</td>

<td> 10 1</td><td>0 0 Channel 1</td><td>32 kHz</td><td>without emphasis</td>

<td> 10 1</td><td>0 1 Channel 1</td><td>32 kHz</td><td>50/15 psec</td>

<td> 10 1</td><td> 1 0</td><td>reserve</td><td></td>

<td> 10 1</td><td>1 1 Channel 1</td><td>48 kHz</td><td>CCITT J.17</td>

<td> 110</td><td>0 0 Stereo</td><td>48 kHz</td><td>CCITT J.17</td>

<td> 110</td><td>0 1 Channel 2</td><td>48 kHz</td><td>CCITT J.17</td>

<td> 110</td><td>1 0 Stereo</td><td>44.1 kHz</td><td>CCITT J.17</td>

<td> 110</td><td>1 I Channel 2</td><td>44.1 kHz</td><td>CCITT J.17</td>

<td>1 1 AND</td><td>0 0 Stereo</td><td>32 kHz</td><td>CCITT J.17</td>

<td> 111</td><td>0 1 Channel 2</td><td>32 kHz</td><td>CCITT J.17</td>

<td> 111</td><td>1 0 Channel 1</td><td>32 kHz</td><td>CCITT J.17</td>

<td>1 1 AND</td><td>1 1 Channel 1</td><td>44.1 kHz</td><td>CCITT J.17</td>

Table 4

Mode Channel I Kanta II stereo 2 mono channel 1 mono channel left program I program I right program II not used

167 271

Table 5

Information Length of allocation samples (awJ in bits

<td>OOOO</td><td></td>

<td> 0001</td><td> 2</td>

<td> 0010</td><td> 3</td>

<td> 0011</td><td> 4</td>

<td> 0100</td><td> 5</td>

<td> 0101</td><td> 6</td>

<td> 0110</td><td> 7</td>

<td> 0111</td><td> 8</td>

<td> 1000</td><td> 9</td>

<td> 1001</td><td> 10</td>

<td> 1010</td><td> 11</td>

<td> 1011</td><td> 12</td>

<td> 1100</td><td> 13</td>

<td> 1101</td><td> 14</td>

<td> 1110</td><td> 15</td>

<td> 1111</td><td>rivet</td>

- (no sample or current scale · transmit ·) by sync detection

<td></td><td></td><td></td><td>Table</td><td> 6</td><td></td><td></td>

<td>gap</td><td> 2:</td><td></td><td></td><td></td><td></td><td></td>

<td>II II-1</td><td>I -2</td><td>II-2</td><td>I-3</td><td>II-3</td><td>I-4</td><td>II-4</td>

<td>gap</td><td> 3:</td><td></td><td></td><td></td><td></td><td></td>

<td>I-5 II-5</td><td>I-6</td><td>II-6</td><td>I-7</td><td>II-7</td><td>I-8</td><td>II-8</td>

<td>gap</td><td> 4:</td><td></td><td></td><td></td><td></td><td></td>

<td>I-9 II-9</td><td>I-10</td><td>II -10</td><td>I-11</td><td>II-11</td><td>I-12</td><td>II-12</td>

<td>gap</td><td> 5:</td><td></td><td></td><td></td><td></td><td></td>

<td>I-13 II-13</td><td>I-14</td><td>II -14</td><td>I-15</td><td>II-15</td><td>I-16</td><td>II-16</td>

<td>gap</td><td> 6:</td><td></td><td></td><td></td><td></td><td></td>

<td>I-17 II-17</td><td>I-18</td><td>II-18</td><td> 1-19</td><td>II-19</td><td> 1-20</td><td>II-20</td>

<td>gap</td><td> 7:</td><td></td><td></td><td></td><td></td><td></td>

<td>I-21 II-21</td><td>I-22</td><td>II-2 2</td><td>I-23</td><td>II-23</td><td>I-24</td><td>II-24</td>

<td>gap</td><td> 8:</td><td></td><td></td><td></td><td></td><td></td>

<td>I-25 II-25</td><td>I-26</td><td>II-26</td><td>I-27</td><td rowspan="2">II-27</td><td>I-28</td><td>II-28</td>

<td>gap</td><td> 9:</td><td></td><td></td><td></td><td></td>

<td>I-29 II-29</td><td>I-30</td><td>II-30</td><td>I-31</td><td>II-31</td><td>I-32</td><td>II-32</td>

<td></td><td colspan="6">T ab e1a 7</td>

<td>gap</td><td> 2:</td><td></td><td></td><td></td><td></td><td></td>

<td>I-1 II-1</td><td>I-2</td><td>II-2</td><td>I-3</td><td>II-3</td><td>I-4</td><td>II-4</td>

<td>gap</td><td>3s</td><td></td><td></td><td></td><td></td><td></td>

<td>I-5 II-5</td><td>I-6</td><td>II-6</td><td>I-7</td><td>II-7</td><td>I-8</td><td>II-8</td>

<td>gap</td><td> 4:</td><td></td><td></td><td></td><td></td><td></td>

<td>I-9 II-9</td><td>I-10</td><td>II-10</td><td>I-11</td><td>II-11</td><td>I-12</td><td>II-12</td>

<td>gap</td><td> 5:</td><td></td><td></td><td></td><td></td><td></td>

<td>I-13 II-13</td><td>- I-14</td><td>II-14</td><td>I-15</td><td>II-15</td><td>I-16</td><td>II-16</td>

167 271

The content of the FD2 frame part in Fig. 2 will be described in more detail with reference to tables 5, 6 and 7. In format A, the second part of the frame contains eight information packets. This is because the adopted Sbb broadband digital signal is converted into 32 subband signals for each part of the Sbb digital signal. An allocation word having a length of four bits is assigned to each subband. This leads to a total of 64 words of allocation, 4 bits each, which can be located in exactly eight information packets. In form B, the second part of the frame holds the allocation information only for half the number of sub-masses, so that the second part of the frame contains only 4 information packets.

Table 5 explains the meaning of the four-bit AW allocation words. The allocation word associated with a specific subband determines the number of bits by which samples of the signals associated with the subband are represented after quantizing in assembly 9. For example, the allocation word Aw 0100 indicates that the samples are represented by 5-bit words. In addition, it results from Table 5 that the allocation word AW 0000 indicates that no sample was created in this subband. This may be the case, for example, if the subband signal in an adjacent subband has such a large amplitude that it completely masks the subband signal in that subband. In addition, allocation word 1111 is not used because it is too similar to the synchronization word in the first IP1 information packet.

Table 6 indicates the order when the frame is in mode A in which the allocation words AW, j, m are associated with two channels j, where j = I or II, and 32 subsequent subbands m, where m is in the range from 1 to 32 are arranged in the second part of the frame. The allocation word AWI, 1 belonging to the first subband signal component of the first and lowest subband (channel I, subband 1) is placed first. After it, the allocation word AWII, 1, belonging to the second subband signal component of the first and lowest subband (channel II, subband 1), is placed in the second part of the FD2 frame. Then, the allocation word AWI, 2 belonging to the first subband signal component of the second and penultimate (channel I, subband 2) is placed in the FD2 frame portion. It is followed by the allocation word AWII, 2 belonging to the second component of the second subband signal (channel II, subband 2). This continues until the AWII allocation word 4 belonging to the second component of the fourth subband signal (channel II, subband 4) is placed in the second part of the FD2 frame. The second IP2 information packet (slot 2) of the frame, which is the first information packet in the second part of the FD2 frame, is therefore completely full. Then the IP3 information packet (slot 3) is filled by aWi, 5; AWII, 5; ... AWII, 8. This continues in the sequence illustrated in Table 6. Table 6 gives only indicators j - m of the allocation words AW, j, m.

Table 7 indicates the order for allocation words for frame B format. In this case, only the words for allocating subbands 1 to 16 are entered. The sequence, as shown in Table 6, corresponds to the sequence in which separate samples belonging to channel j and subbands m are fed to the synthesis filter after being received at the receiver. For example, a serial data stream only contains frames in accordance with the A format. The allocation information in each frame is therefore used in the receiver to correctly input the samples from the information in the third part of the frame. However, the serial data stream may also contain more or less alternating both A and B format compliant systems. However, frames compatible with both formats may contain samples for all channels and all subbands in the third part of the frame. The B format frame does not actually contain the allocation information required to derive samples from channels I or II of subbands 17 to 32 from the third part of the frame.

The receiver contains a memory in which the allocation information contained in the second part of the A format frame is stored. If the next frame is in B format, only the allocation information for subbands 1 to 16 and channels I and II is replaced in memory by the allocation information contained in the second part of the B, A format frame for output of samples for subbands 17 to 32 from the third part B-format frames, the allocation information for these subbands is used, derived from the preceding A-format frame and still contained in memory. The reason for the alternating use of A and B format frames is that the allocation information for some subbands does not change rapidly for the higher subbands 17 to 32. Because the allocation information for different subbands is available in the transmitter during quantization, it can decide to create a format frame B instead of A format if it doesn't change much

167 271 allocation information for subbands 17 to 32 inclusive. In addition, this indicates that additional space is available for including samples in the third part of the FD3 frame. The third part of the B format frame is, for certain P 'values, four information packets longer than the third part of the A format frame. Consequently, this allows the number of bits representing the samples in the lower subbands 1 to 16 to increase, so that greater accuracy is achieved transmission for these subbands. Furthermore, if lower subbands are quantized with greater accuracy, the transmitter can automatically choose to generate a B format frame. This can be at the expense of the accuracy with which the higher subbands are quantized.

The third part of the FD3 frame in Fig. 2 contains samples of quantized subband signal components for two channels. If the allocation word is 0000, it is not present in the FD2 frame portion for each subband channel and it means that in the example shown, twelve samples are introduced into the third part of the FD3 frame for each of the 32 subbands and 2 channels. This means that there are 768 samples in total. Samples can be multiplied by a scale factor in the transmitter before being quantized. The amplitudes of these twelve samples for each subband and channel are divided by the amplitude of the sample of the twelve samples that has the largest amplitude. The scale factor in this case should be transmitted for each subband and channel to allow reverse sampling on the receiving side. The third part of the frame then contains the scale factors SF j, m, one for each of the quantized components of the subband signals on the different subbands. The scale factors in the example shown are represented by a 6-bit number, the first most significant bit, in the range from 000000 to 111110. The scale factors of the subbands, for which they are located, i.e. for which the allocation information is not zero, are sent before starting sample transmission. This means that the scale factors are located in the leading portion of the FD3 frame, before the samples. This makes it possible to achieve fast decoding at the receiver 5, without having to memorize all samples at the receiver. The SF scale factor j, m then represents the value by which the signal samples in the jth channel of the mth subband were multiplied. Conversely, the number one divided by said value is stored as a scale factor, so that it is not necessary to divide the scale factors on the receiving side before the samples are scaled to the correct values.

The largest number of scale factors is 64 for the A format frame. If the allocation word AW j, m for the specified subband m is 0000, it means that for this channel and this subband there is no sample in the FD3 frame portion. It is therefore not necessary to enable the scale factor for this channel and this subband. The number of scale factors is then less than 64. The order in which the scale factors SF j, m are placed in the third part of the FD3 frame is the same in which the allocation words were entered into the second part of the frame. The sequence is therefore: SFI, 1; SF II, 1; SF I, 2; SF II, 2; SF I, 3; SF II, 3 ... SF I, 32; SF II, 32. This sequence will be incomplete if you do not need to enter a scale factor. The sequence can then be, for example:

.... SF I, 4; SF I, 5; SF II, 5 SFII, 6; ....

Scale factors for the fourth subband of channel II and the sixth subband of channel I are not entered in this case. If the frame is in B format, you can still consider entering a scale factor to the third part of the frame for all subbands and all channels. However, this is not necessary. In this case, it will be possible to enter scale factors in the third part of the frame only for subbands 1 to 16. This requires memory in the receiver, where the scale factors will be stored until the previous A format frame is received. Then, after adopting the B format frame, the scale factors for subbands 1 to 16 are replaced by the scale factors contained in the B format frame. Then the scale factors are used a previously received A format frame for subbands 17 to 32 to restore samples for these subbands contained in the third portion of the B format frame to the correct scale.

Samples are introduced into the third part of the FD3 frame in the same sequence as the allocation words and scale factors, one sample for each subband of each channel, in order. It means; first all first samples for quantized subband signals for

167 271 of all subbands of both channels, then all the second samples, etc. The binary representation of the samples is arbitrary, e.g. a binary word containing only ones will not be used again.

The second digital signal generated in the transmitter 1 is then fed to the transmission center 4 through the output 7 and via this center 4 this signal is transmitted to the receiver 5. The transmission through the transmission center 4 can be wireless, e.g. via a radio channel. However, other transmission centers are also possible. For this reason, optical transmission can be imagined, e.g. via optical fiber, or optical recording media, e.g. compact disk type center, or transmission via magnetic recording media.

The receiver 5 includes a decoder 21 that decodes the signals encoded in the encoder 6 of the transmitter 1 and converts them into a copy of the broadband digital signal fed to output 8.

Figure 5 shows the receiver version 5 of Figure 4 in detail. The encoded signal (digital signal) is fed to the scale factor information detector in the form of a switch 11 via terminal 10. The essential information of the incoming signal is contained in the scale factors and samples. Other information in the second digital signal is only required for proper data ordering to enable correct decoding. The decoding process is repeated for each incoming frame. The transmitter first extracts synchronization and system information from the frame. The synchronization information detector 19 recognizes each time the synchronization words located in the first 16 bits of the first part of each frame. Since the synchronization words of successive frames are each time separated by an integer multiple of P 'or P' + 1 packets of information, the synchronization words are recognized very accurately. If only the transmitter is in synchronization state, the word synchronization is detected in a detector 19, which has a time window of, for example, one information packet length. It is open at all times P 'of information packets, so that only this part of the incoming information is fed to the sync word detector in detector 19. If the sync word is not detected, the time window remains open for the duration of the second information packet, because the preceding frame may be a frame containing P '+ 1 information packets. From the words of synchronization, the synchronous phase loop in the detector 19 can output a clock signal to control the central processor 18. It is obvious that the receiver should know how many information packets are contained in one frame. For this purpose, the system information uses switching systems 15 via the processor input 18, which switching systems are then in the position shown. System information is now stored in memory 18a of the packet number detector - processor 18. Information about the number of information packets in the frame is fed to the detector 19, via control signal lines 20, to open the time window at the right moments for detecting the word synchronization. The switch 15 goes to the lower position after receiving the system information. The allocation information in the second part of the frame is now stored in memory 18b - the signal information detector. If the allocation information in the incoming frame does not contain the allocation word for all subbands and channels, it will be visible from the detected system information. This can be, for example, information indicating whether the frame is in A or B format. Processor 18, under the influence of the information contained in the system information, will remember the received allocation words in the correct place in the allocation memory 18b. It is obvious that in the example shown, allocation memory 18b contains 64 memory positions. If no scale factors are transmitted, the system elements marked with numbers 11, 12 and 17 can be omitted and the content of the third part of the frame can be brought to the decoder in the form of a synthesis filter 21, through input 10, which is coupled to the filter input, through connection 16. Sequence in which the samples are fed to the filter system 21 is the same as the sequence in which the filter 21 processes the samples to reproduce the broadband signal. The allocation information stored in memory 18b is necessary to divide the serial data stream into individual samples in the filter system 21, each sample with the correct number of bits. To this end, the allocation information is fed to the filter system 21 via line 22. The receiver further includes a de-emphasis assembly

167 271

23, which de-emphasizes the reconstructed digital signal provided by the filter 21. For correct de-emphasis, the corresponding information in bits 24 to 31 of the first part of the frame should be provided from memory 18a to the de-emphasis assembly 23 via line 24.

If the third part of the frame also contains SF scale factors j, m, the receiver will contain switch 11, memory 12 and multiplier 17. Switch 11 is in the down position under the influence of the control signal supplied by processor 18 through line 13, at all these times, in which the third part of the FD3 frame reaches. The scale factors are then delivered to memory 12. The scale factors are stored in the correct location in memory 12 under the influence of address signals delivered to this memory 12 by processor 18 on line 14. Memory 12 has 64 locations for storing 64 scale factors. On the other hand, if a B format frame is received, the processor 18 provides such address signals to memory 12 that only the scale factors for subbands 1 to 16 are deleted by the B scale frame factors. Then, switch 11 changes position to the upper position under the influence of the control signal supplied through line 13, so that the samples are fed to the multiplier 17. Under the influence of the allocation information now provided to the multiplier 17 through line 22, the multiplier outputs individual samples of the correct length bits, forming a serial data stream, supplied through line 16. Samples are then multiplied to return them to the correct sample conditions before scaling at the transmitter. If the scale factors stored in memory 12 are the scale factors by which the samples were scaled in the transmitter, then these factors should first be inverted (one divided by the scale factor) and then only brought to the multiplier 17. Of course, it is also possible to invert the scale factors after admission, before saving them to memory 12. If the scale factors in the frames are already equal to the value by which the samples should be scaled, they can be saved directly to memory 12 and can be fed directly to the multiplier 17. It is obvious that no memory is required to save all these samples, until no processing signal occurs after the samples contained at the beginning of the frames. By the time the sample arrives, via line 16, all the information required to process the sample is already available, so that processing can be carried out immediately.

This whole process is started by control signals and clock signals delivered to all transmitter components by processor 18. Not all control signals are shown in the figure. This is not necessary because the operation of the receiver is obvious to those skilled in the art. The multiplier 17 multiplies the samples by the correct factors under the control of the processor 18. Samples restored to the correct amplitude are fed to the reproduction filter 21, the decoder, in which the subband signals are reproduced to a broadband digital signal.

Figure 6 schematically shows another version of the transmitter in the form of a recording device for recording a wideband digital signal on a recording medium. In the present case, on a magnetic recording medium 25. Encoder 6 provides a second digital signal to a recording device 27, including a head 26, through which the signal is recorded on the recording medium path. It is then possible to record the second digital signal on a single track of the recording medium, for example via a spiral-dial recorder in which the single path is actually divided into side-by-side paths that are inclined with respect to the longitudinal direction of the information carrier. An example is the RDAT registration method. Another way is to divide the information and simultaneously register on multiple side-by-side paths that lie on the record carrier in its longitudinal direction. Consider using the SDAT registration method here.

It should be noted that the signal fed to the encoder 6 can first be encoded in the signal converter. This coding can again be a 8 to 10 conversion followed by interleaving as described with reference to Fig. 4. If the coding information is recorded on the recording medium on many adjacent parallel paths, the signal converter should also be able to allocate the coding information to different paths.

167 271

Figure 7 schematically shows a version of the receiver 5, which in the present case takes the form of a reading device of the recording medium 25 on which the broadband digital signal is recorded in the form of a second digital signal, by means of the device shown in Fig. 6. The second digital signal is read from the path on recording medium 25 through the head 29 and is provided to the receiver 5 as shown in figure 5. The third signal receiving circuit in the form of a reading device 28 may be constructed for reproduction by known methods of RDAT or SDAT. If the signal provided by the encoder 6 in the recording device 27 shown in Fig. 6 is to be processed, for example, in 8 to 10 conversion and in the form of interleaving, then the encoded signal, read from the recording medium 25, should first be subjected to the process of reverse interleaving and conversion 10 to 8. In addition, if the encoded signal has been recorded on multiple parallel paths, then the reproduction apparatus shown in Fig. 7 should collate the information read from these paths in the correct sequence before further processing.

Figure 8 shows several other possibilities for introducing scale factors and samples into the third part of the FD3 frame. Fig. 8a illustrates the described method in which the SF scale factors for all subbands and channels (I or II) are introduced into the third frame before samples. Fig. 8b illustrates the same situation as in Fig. 8a, but in this case the memory capacity is schematically shown for the SF I, m and SF II scale factors, and associated x samples for these two channels in the m subbands. Fig. 8b shows the samples for two channels in the m subband connected into blocks, while normally they are spread out in the third part of the frame. Samples have a length of y bits. In the example above x was taken as 12 and y was taken as 8. Fig. 8c shows a different format. The two scale factors for the first and second channel in the subband are still present in the third part of the frame. However, instead of x samples for both channels (left and right channels for the stereo signal) in the m subband (i.e. 2x samples in total). Only x samples for the subband m are contained in the third part of the frame. These x samples were obtained, for example, by mutually adding corresponding samples in each of the two channels. In fact, a mono signal was obtained in this subband m. Each of the samples in Fig. 8c is a bit length. If z is equal to y, space in the third part of the frame is saved, which can be used for samples requiring more accurate quantization. It is possible to express x samples of mono signal with wz = 2y (= 16) bits. This signal processing is used if the phase difference between the left and right components of the subband signal is negligible, but the waveform of the monophonic signal is important. This applies in particular to signals in higher subbands, because the phase phase sensitivity of the ear for frequencies in these subbands is lower. By expressing x 16-bit mono signal samples, the waveform is quantized more accurately, while the space occupied by these samples in the third part of the frame is the same as that in the example illustrated in Fig. 8b. Still another option is to show the samples in Fig. 8, for example by 12 bits. Signal determination is then more accurate than in the example illustrated in Fig. 8b, with additional space being saved in the third part of the frame. When on the receiving side the signals contained in the third part of the frame, as shown in Fig. 8c, are reproduced, a stereo effect is obtained, which is referred to as intense stereo. Here only the signal intensity of the left channel and right channel (in the subband m) can differ due to different values ​​of the SF I, m and SF II, m scale factors.

Figure 8d gives yet another case where there is only one scale factor SFm for both signal components in the m subband. This is a situation that may occur in particular for low frequency subbands.

Yet another possibility that is not shown is the case when x samples for channels I and II of the subband m, as in Fig. 8b, are not associated with the scale factors SF I, m and SF II, m. Consequently, scale factors are not entered in the same third part of the frame. In this case, the SF I, m and SF II, m scale factors contained in the third part of the previous frame must be used to scale the samples in the receiver.

All of the possibilities described with reference to Fig. 8 can be used in the transmitter to achieve the most efficient data transfer through the transmission center. Therefore, the frames described in relation to Fig. 8 can occur in the data stream

167 271 alternatively. If the receiver is to be able to correctly decode these different frames, then information about the structure of these frames should be included in the system information.

Figure 9 shows the transmitter 1 in more detail. The figure shows how different pieces of information can be combined to form a serial data stream, as shown in Figs. 12 and 3. Fig. 9 actually shows a detailed version of the encoder 6 in the transmitter 1. The encoder includes a frame generator 30 constituting a central processor that controls several encoder devices. Encoder 6 includes a synchronization information and system information generator 31 as described in connection with Figs. 3, generator 32 determining allocation information, additional circuit 33, scale factor designations, generator 34 determining samples for the frame. An information packet generator 35 capable of generating an additional IP P '+ 1 information packet. The outputs of these generators are coupled to the associated inputs of the signal switching circuit 40 in the form of a five-position switch whose output is connected to the output of the encoder 6. The switching system 40 is also controlled by a processor . Individual generators are controlled via lines 41.1 to 41.4.

The transmitter's operation will be described for a mono signal divided into M subband signals. These M signals from the Ssbi to Ssbb subbands are connected to terminals 45.145.2, ... 45.M. For example, blocks of 12 samples from each of the subband signals are taken together. In teams

46.1 to 46.M, if present, twelve samples in a block are scaled to the amplitude of the largest sample in the block. M scale factors are fed to assembly 33 via lines 47.1 to 47.M. The subband signals are delivered to M 48.1 to 48.M quantizers and to set 49. For each subband, set 49 determines the number of bits with which the associated subband signals should be quantized. This information is provided to the appropriate 48.1 to 48.M quantizers through 50.1 to 50.M lines, so that the quantizers correctly quantize 12 samples from each of the subband signals. In addition, allocation information is provided to assembly 32. Samples of quantized subband signals are delivered to assembly 34 via lines 51.1 to 51 .M. Teams 32, 33 and 34 put the allocation information, scale factors, and samples in the correct order. In addition, the central processor 30 generates synchronization information and system information related to the generated frame into which said information stored in units 32, 33 and 34 should be entered. In the position of the signal switching circuit 40 shown, the synchronization and system information for the frame is provided by the generator 31 and fed to output 7. Then the switch 40 is set to the second position from above under the influence of the control signal supplied by the central processor 30 via line 53, so that the output of the generator 32 is connected to the output 7. The allocation information is now provided by the generator 32 to output 7. The sequence of the allocation information is as shown in relation to table 6 or 7. Then, switch 40 is shown in the third position from above. That is, the output of circuit 33 is connected to the output

7. Circuit 313 now supplies scale factors in the correct sequence to output Ί. The switch 40 is then set to the next position so that the output of the generator 34 is connected to the output 7. The generator 34 now delivers to the output 7 samples on different subbands in the correct sequence. In this cycle exactly one frame is delivered to the output7. Then, switch 40 is returned to the up position. A new cycle begins, in which the next block of 12 samples for each subband is coded and the next frame at output 7 is generated.

In some cases, for example, when the sampling frequency F is 44.1 kHz (table 5) an additional information packet (empty slot in figure 2) must be added. In this case the switch will be set starting from the position in which the generator 34 is connected to the lower position. The output of the generator 35 is now connected to the output 7, and the generator 35 generates an additional IP information packet P + 1, which is connected to the output 7. Then switch 40 is reset to the upper position to start the next cycle.

It is obvious that if the errors received during signal transmission are corrected in the signal received by the transmitter, the specific channel code should be provided to the second digital signal. In addition, modulation of the second digital signal is required before transmission. In this way, the digital signal is transmitted through the site

167 271 transmission, which signal may not be directly identified as the second signal, but it may be derived from it. In the case where the subbands have different widths, the number of samples for the different subbands entered in one third of the frame may vary and probably differ. Assuming that the division into three subbands, the lower SB1 subband, the central SB2 subband, and the upper SB3 subband is used, the upper SB3 subband will have a bandwidth that is, for example, twice the size of the other two subbands. Does this mean that the number of samples derived in the third part of the frame for the SB subband? it is also twice as large for the other subbands. The order in which samples are delivered to the reproduction filter in the receiver can be: first sample from SB1, first sample from SB3, first sample from SB2, second sample from SB3, second sample from SB1, third sample from SB3, second sample from SB2, the fourth sample from SB3, ... etc. The order in which the allocation information is entered for these subbands in the second part of the frame is as follows: the first SB1 allocation word, followed by the SB3 allocation word, then the SB2 allocation word. The same applies to scale factors. In addition, the receiver can deduce from the system information that in this case the cycle contains groups of four samples each and each group contains one sample from SB1, one sample from SB3, one sample from SB2 and then a second sample from SB3.

Figure 10 shows another structure of the first part of the FD1 frame. The first part of the FD1 frame contains exactly 32 bits and therefore corresponds to one packet of information. The first 16 bits are a synchronization signal or a synchronization word. The synchronization word may be the same as the synchronization word of the first part of the FD1 frame shown in Fig. 3. The information located in bits 16 to 31 differs from the information contained in bits 16 to 31 of Fig. 3. Bits bi6 to bi9 represent the bit rate indicator (BR indicator). The bit rate indicator is a 4-bit number whose values ​​are shown in the table

8. If the bit rate indicator is the equivalent of a 4-bit digital number in the form of ooo, this means a free format condition, which means that the bit rate is not specified and that the recognition of the beginning of a new frame in the decoder depends only on the word synchronization. The 4-bit 1111 digital number is not used so as not to interfere with the recognition of the synchronization word. The bit rate is shown in the second column of Table 8 as a decimal number corresponding to a 4-bit binary number. Corresponding bit rate values ​​are given in column 1.

Bits 20 and 21 represent the sample rate Fs, see table 8.

Table 8 shows the four possibilities of 2-bit binary numbers for b20 and b21 and associated sampling rate. Bii 22 indicates whether the frame contains a empty slot when b22 = 1, or does not contain an empty slot, and then b22 = 0. The information in bits to b22 allows you to specify the number of information packets in the current frame. This means again that the first part of the frame contains information about the number of information packets in the frame when ns is known. This determines the number of samples of the broadband signal that corresponds to the information belonging to the second digital signal and is located in one frame. In the presented example n = 384, it is possible to determine the number of B information packets in the frame, using the data in Table 4, the fill bit b22 and the relationship:

BR

N

<img file="PL167271B1_D0001.tif" />

Bit b23 is intended to determine the future expansion of the system. For now, it has been assumed that this bit is 0. The contents of the first part of the frame regarding bits b24 to b31 will be described with reference to Fig. 11 and Table 9. Bits b24 and b25 give an indication of the mode for the audio signal.

For the four possibilities of this two-bit binary number, Table 9 shows whether the broadband digital signal is an stereo (OO) acoustic signal, mono (11) signal, bilingual (10) signal or intense stereo (01) acoustic signal. In the last example, bits 26 and 27 indicate which subbands processed according to the intensive stereo method.

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Table 9 indicates, for the corresponding two-bit numbers 00,01,10 and 11, that the subbands

5-32, 9-32, 13-32 and 17-32 were processed according to the intensive stereo method. As already stated, intense stereo can be used for higher subbands because the ear is less phase sensitive for frequencies in these subbands. Bit b28 can be used as a copyright bit. If this bit is 1, it means that the information is copy-protected and should not / cannot be copied, Bit b29 may indicate that the information is original (b29 = 1), for example in the case of recorded tapes, or that the information was copied (b29 = 0).

Table 8

Bits 16 to 19: nskain how many bit rates, bit rates

BR BR frequency frequency transcoding Fs mission bits nik 48 nHz 44.1 kHz 32 kHz / niitbi / s / number number number of slots slots slots

<td> 32</td><td> 1</td><td> 8</td><td> 8</td><td> 12</td>

<td> 64</td><td> 2</td><td> 16</td><td> 17</td><td> 24</td>

<td> 96</td><td> 3</td><td> 24</td><td> 26</td><td> 36</td>

<td> 128</td><td> 4</td><td> 32</td><td> 34</td><td> 48</td>

<td> 160</td><td> 5</td><td> 40</td><td> 43</td><td> 60</td>

<td> 192</td><td> 6</td><td> 48</td><td> 52</td><td> 72</td>

<td> 224</td><td> 7</td><td> 56</td><td> 60</td><td> 84</td>

<td> 256</td><td> 8</td><td> 64</td><td> 69</td><td> 96</td>

<td> 288</td><td> 9</td><td> 72</td><td> 78</td><td> 108</td>

<td> 320</td><td> 10</td><td> 80</td><td> 87</td><td> 120</td>

<td> 352</td><td> 11</td><td> 88</td><td> 95</td><td> 132</td>

<td> 384</td><td> 12</td><td> 96</td><td> 104</td><td> 144</td>

<td> 416</td><td> 13</td><td> 104</td><td> 113</td><td> 156</td>

<td> 448</td><td> 14</td><td> 112</td><td> 121</td><td> 168</td>

+ filling

Bits 20 and 21: Sampling frequency

<td> 0</td><td> 0</td><td> 44.1</td><td>NZZ</td>

<td> 0</td><td> 1</td><td> 48</td><td>NZZ</td>

<td> 1</td><td> 0</td><td> 32</td><td>NZZ</td>

<td> 1</td><td> 1</td><td>res</td><td>erwowane</td>

Bit 22: the fill bit if the frame has an empty slot, otherwise O

Bit 23: Future application is reserved for future application 0 for the present time

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Bits b30 and b31 specify the emphasis that can be applied to the broadband signals in the transmitter.

A different configuration of the second part of the FD2 frame will now be presented for the different indication modes represented by bits b24 to b27 in the first part of the frame. The second part of the frame contains a 4-bit allocation word, the meaning of which is described in relation to Table 5. For stereo mode (b24, b25 = 00) and bilingual mode (b24, b25 = 10) the second part of the FD2 frame has a length of 8 information packets (slots ) and is created as described in table 6. In stereo mode, I in Table 6 represents the left channel component, and II the right channel component. For bilingual mode, I means one language and II means the second language. For mono mode (b24, b25 = 11) the length of the second part of the FD2 frame is only 4 information packets (slots).

Table 10 illustrates the order of words for different subbands 1 to 32 in four information packets (slots) 2 to 5. Therefore, each amount M - i represent four-bit allocation words that determine the number of bits in each sample in the subband of the next number and where are in the range 1 to 32. In the intensive stereo mode (b24, b25 = 01) there are four possibilities indicated by bits b26 and b27, see table 9. All these possibilities result from the different contents of the second part of the FD2 frame.

Table 11 illustrates four different contents of the second part of the frame. If the switching bits b26, b27 are 00, then the signals in subband 1 to 4 are normal stereo signals, and the signals in subband 5 to 32 are intense stereo signals.

Table 9

Bits 24 and 25: Display mode

<td></td><td></td><td></td><td> 0</td><td> 0</td><td>stereo</td>

<td></td><td></td><td></td><td> 0</td><td> 1</td><td>intense stereo</td>

<td></td><td></td><td></td><td> 1</td><td> 0</td><td>bilingual</td>

<td></td><td></td><td></td><td> 1</td><td> 1</td><td>mono</td>

<td>beaten</td><td> 26</td><td>and 27:</td><td colspan="3">Switching to intense stereo mode</td>

<td></td><td> 0</td><td>0 subbands</td><td> 5-32</td><td>in</td><td>intense stereo mode</td>

<td></td><td> 0</td><td>1 subband</td><td> 9-32</td><td>in</td><td>intense stereo mode</td>

<td></td><td> 1</td><td>0 subbands</td><td> 13 - 32</td><td>in</td><td>intense stereo mode</td>

<td></td><td> 1</td><td> 1</td><td> 17 - 32</td><td>in</td><td>intense stereo mode</td>

<td>bit</td><td> 28:</td><td colspan="2">Copyright</td><td> 0</td><td>no copyright</td>

<td></td><td></td><td></td><td></td><td> 1</td><td>copy protected</td>

<td>bit</td><td> 29:</td><td colspan="2">Original / Self</td><td> 0</td><td>duplication</td>

<td></td><td></td><td>copy</td><td></td><td> 1</td><td>Original</td>

<td>beaten</td><td> 30</td><td colspan="2">and 31: Emphase</td><td> 0</td><td>0 without emphasis</td>

<td></td><td></td><td></td><td></td><td> 0</td><td>1 emphasis 50/15 / is</td>

<td></td><td></td><td></td><td></td><td> 1</td><td>0 reserved</td>

<td></td><td></td><td></td><td></td><td> 1</td><td>1 CCITT J.17</td>

<td>Mode</td><td colspan="2">mono:</td><td colspan="3">Table 10</td>

M = mono signal slot 2:

<td>M-1</td><td></td><td>M-2</td><td>M-3</td><td>M-4</td><td>M-5</td><td>M-6</td><td>M-7</td><td>M-8</td>

<td>gap M-9</td><td> 3</td><td>M-10</td><td>M-11</td><td>M-12</td><td>M-13</td><td>M-14</td><td>M-15</td><td>M-16</td>

<td>gap M-17</td><td> 4</td><td>M-18</td><td>M-19</td><td>M-20</td><td>M-21</td><td>M-22</td><td>M-23</td><td>M-24</td>

<td>gap M-25</td><td> 5</td><td>• • M-26</td><td>M-27</td><td>M-28</td><td>M-29</td><td>M-30</td><td>M-31</td><td>M-32</td>

167 271

This means that for subbands 1 to 4 for the left and right channel components in these subbands, the associated allocation word should be written in the second part of the frame. In Table 1la, this is represented by subsequent AW allocation words (1,1); AW (R, 1); AW (1,2); AW (R, 2); ... AW (R, 4), stored in the slot of the second frame, i.e. in the first slot of the second frame. Table 11 a gives only indicators (i - j) of allocation words, and is equal to L or R and indicates the left and right channel components, respectively, aj varies from 1 to 4 and represents the subband sequence number. For subbands 5 to 32, the left and right channel components contain the same series of samples. The only difference is in the scale factors for the left and right channel components in the subband. Consequently, such a subband requires only one allocation word. The allocation words Aw (i, j) for these subbands 5 to 32 are indicated by the indicators Mj, where i is consistently equal to M for all subbands, aj is in the range of 5 to 32.

Table 11 a indicates that a 4 and 1/2 information packet is required to enter 36 allocation words in the second part of the frame. If the switching bits bi6, bn are 01, then the signals in subbands 1 to 8 will be normal stereo signals, and the signals in subbands 9 to 32 will be stereo intense signals. This means that for each subband 1 to 8, two allocation words AW (L, j) and AW (R, j) are required, and for each of the subbands 9 to 32 only one allocation word Aw (M j) is required. It follows that a total of 40 allocation words contained in five information packets (slots), i.e. IP2 to IP6 of the frame, are needed. This is shown in Table 11b. In this case, the major part of the FD2 frame is five information packets (slots).

If the switching bits b26, b ^ 7 are 10, then the signals in subbands 1 to 32 will be normal stereo signals, and the signals in subbands 13 to 32 will be stereo intense signals.

Table 11c gives the structure of the second part of the FD2 frame with allocation words for different subbands. The second part of the frame is 5 M2 information packets (slots) to locate all allocation words. If the switching bits b26, b27 are 11, then the signals in subbands 1 to 16 will be normal stereo signals, and the signals in subbands 17 to 32 will be stereo intense signals. You now need 48 allocation words that are entered into the second part of the frame with 6 information packets (slots), see Table 11d.

What has been said before about scale factors is also important today. After assuming that the allocation word 0000 is not assigned to either subband or channel, 64 scale factors are required for both stereo and intensive stereo modes. This is because in all modes, intensive stereo, each mono subband should have two scale factors to enable the implementation of intensive stereo, for the left and right channels in this subband, piiti^-^ Fig. 8c.

It is obvious that in mono mode the number of scale factors is half, i.e. 32, assuming again that the allocation word 0000 is not assigned to any of the subbands.

Figure 13a shows the largest ISmaJ sample. The first bit marked SGN is the sign bit and is 0 because it refers to the absolute value of ISmaJ. Samples are presented in two complementary entries. The samples contained the leading zeros 1. The values ​​of the other bits of the 24-bit binary number are not significant and can be both 0 and 1.

ISmaJ is then multiplied by 2^kas shown in Fig. 13b. Then ISmaJ · 2^kis compared with the binary DVi number 0101000011000000000000 and the binary DV number₂ equal to 011001100000000000000000. If 1 SmaJ · 2k &lt;DV t then the specified constant p is assumed to be 2. If DV1 &lt;I Smax I-23k &lt;DV2, then p is assumed to be 1. If SmaJ · 2k&gt; DV₂, then p = 0. The number k is limited to the range 0 &lt;k &lt;20. The scale factor is now determined by the numbers kip, as follows:

SF = 3k + p.

Consequently, the largest value for SF is 62. This means that the scale factors can be represented by 6-bit numbers, the six-bit number 111111 (which corresponds to a decimal number of 63) is not used. In fact, 6-bit binary numbers are not scale factors, but they clearly define the relationship with real scale factors. All 12 S samples are multiplied by the number associated with the k and p values. These 12 samples are multiplied as follows:

S '= S -2k · g (p) where the number g (p) is related to the constant p as follows:

g (p) = 1 for p = 0

167 271 g (p) = 1+ 2 '² + 2'⁸ + 2'¹⁰ + 2'¹⁶ + 2'¹⁸ + 22³ for p = 1 g (p) = 1+ 2^l + 2-4 + 2’⁶ + 2'⁸ + 2'⁹ + 2’1° + 2¹³ + 2⁴⁵ +2'¹⁶ + 2⁴⁷ + 2‘” + 2'²⁰ for p = 2. Table 11

<td>and·</td><td colspan="2">Intense stereo mode</td><td></td><td></td><td></td><td></td>

<td></td><td>L - left channel, a</td><td colspan="3">- right channel, M -</td><td colspan="2">mono signal</td>

<td></td><td>Switching bits</td><td>/ bits</td><td colspan="2">26 and 27 / are</td><td> 0 0:</td><td></td>

<td></td><td>gap 2: L-1 R-1 L-2 gap 3:</td><td>R -2</td><td>L-3</td><td>R-3</td><td>L-4</td><td>R-4</td>

<td></td><td>M-5 M-6 M-7</td><td>M-8</td><td>M-9</td><td>M-10</td><td>M-11</td><td>M-12</td>

<td></td><td>gap 4: M-13 M-14 M-15 gap 5:</td><td>M-16</td><td>M-17</td><td>M-18</td><td>M-19</td><td>M-20</td>

<td></td><td>M-21 M-22 M-23 gap 6:</td><td>M-24</td><td>M-25</td><td>M-26</td><td>M-27</td><td>M-28</td>

<td></td><td>M-29 M-30 M-31</td><td>M-32</td><td></td><td></td><td></td><td></td>

<td>b.</td><td>Switching bits gap 2:</td><td>are 0</td><td> 1;</td><td></td><td></td><td></td>

<td></td><td>L-1 R-1 L-2 gap 3:</td><td>R-2</td><td>L-3</td><td>R-3</td><td>L-4</td><td>R-4</td>

<td></td><td>L-5 a-5 L-6</td><td>R-6</td><td>L-7</td><td>R-7</td><td>L-8</td><td>R-8</td>

<td rowspan="2"></td><td rowspan="2">gap 4: M-9 M-10 M-11 gap 5:</td><td rowspan="2">M-12</td><td rowspan="2">L-13</td><td rowspan="2">M-14</td><td rowspan="2">M-15</td><td>M-16</td>

<td></td>

<td></td><td>M-17 M-18 M-19 gap 6:</td><td>M-20</td><td>M-21</td><td>M-22</td><td>M-23</td><td>M-24</td>

<td></td><td>M-25 M-26 M-27</td><td>M-28</td><td>M-29</td><td>M-30</td><td>M-31</td><td>M-32</td>

<td>c.</td><td>Switching bits gap 2:</td><td>are 1</td><td>Axis</td><td></td><td></td><td></td>

<td></td><td>L-1 R-1 L-2</td><td>R-2</td><td>L-3</td><td>R-3</td><td>L-4</td><td>R-4</td>

<td></td><td>gap 3: L-5 R-5 L-6 gap 4:</td><td>R-6</td><td>L-7</td><td>R-7</td><td>L-8</td><td>R-8</td>

<td></td><td>L-9 R-9 L-10 gap 5:</td><td>R-10</td><td>L-11</td><td>R-11</td><td>L-12</td><td>R-12</td>

<td></td><td>M-13 M-14 M-15 gap 6:</td><td>M-16</td><td>M-17</td><td>M-18</td><td>M-19</td><td>M-20</td>

<td></td><td>M-21 M-22 M-23 gap 7:</td><td>M-24</td><td>M-25</td><td>M-26</td><td>M-27</td><td>M-28</td>

<td></td><td>M-29 M-30 M-31</td><td>M-32</td><td></td><td></td><td></td><td></td>

<td>down</td><td>Switching bits gap 2:</td><td>are 1</td><td> 1:</td><td></td><td></td><td></td>

<td></td><td>L-1 R-1 L-2</td><td>R -2</td><td>L-3</td><td>R_3</td><td>L-4</td><td>R-4</td>

<td></td><td>gap 3: L-5 R-5 L-6 gap 4:</td><td>R-6</td><td>L-7</td><td>R-7</td><td>L-8</td><td>R-8</td>

<td></td><td>L-9 R-9 L-10 gap 5:</td><td>R-10</td><td>L-11</td><td>R-11</td><td rowspan="2">L-12 L-16</td><td rowspan="2">R-12 R-16</td>

<td rowspan="2"></td><td rowspan="2">L-13 R-13 L-14 gap 6:</td><td rowspan="2">R-14</td><td rowspan="2">L-15</td><td rowspan="2">R-15</td>

<td></td><td></td>

<td></td><td>M-17 M-18 M-19 gap 7:</td><td>M-20</td><td>M-21</td><td>M-22</td><td>M-23</td><td>M-24</td>

<td></td><td>M-25 M-26 M-27</td><td>M-28</td><td>M-29</td><td>M-30</td><td>M-31</td><td>M-32</td>

167 271

The parameter k specifies the number of 6 dB steps, and the g (1) and g (2) coefficients are approximations to 2 dB steps. Such scaled S 'samples are now quantized to allow them to be represented by q-bit binary numbers in two complementary notations. This is illustrated in Figure 14 for q = 3. The scaled samples S 'have values ​​between +1 and -1 (Figure 14a). These samples must be represented in the quantization by q-bits, where q corresponds to the allocation value for the associated subband (channel). Because the binary number containing only ones is not used, the entire range from -1 to +1 should be divided into 2q-1 smaller intervals to represent the sample. To this end, the scaled S 'samples are processed into S' samples, according to the relationship

S "= S '(1-2-) 2.

Samples S "are then cut at q bits, see Fig. 14c.

Because representation 111 is not allowed, the sign bits are inverted, see Fig. 14d. The q (= 3) -bit numbers shown in Fig. 14d are entered into the third part of the FD3 frame (Fig. 2).

Samples S 'which satisfy the inequality -0.71 &lt;S' &lt;-0.14 are represented by the binary number 001. This is done similarly for samples S 'with a higher value, up to samples that satisfy the inequality 0.71 &lt;S '&lt;1, which represented by the binary number 110. Consequently, the binary number 111 is not used.

The decanting on the receiving side is the reverse of the quantizing on the transmitting side (Fig. 15). That is, the first bits of the sign of q-bit binary numbers are inverted to obtain the normal two complementary notations (Fig. 15b).

Then the S 'samples are derived from the transformed S' samples, maintaining the relationship:

S '= (S "+2'^{q + 1}) (1 +2’^q+2'^2q + 2'^3q + I '⁴- + ...) as shown in Figs. 15c and 15d.

The S 'values ​​obtained in this way are located exactly in the initial intervals of Fig. 14a. The samples are then scaled on the receiving side to the original amplitudes using the transmitted information about the parameters k, p, which are associated with scale factors. So the number q '(p) on the receiving side results from the relationship:

q '⁽p) = ld^la p = 0, q '(p) = 2¹ + 2'² + 2’⁵ + 2‘⁶ for p = 1 q '(p) = 2- + 2-³ + 2-⁸ + 2-⁹ d! p = 2.

Scaling to original amplitudes is performed using the following relationship:

S = S '.2 ». g '(p).

In two possible versions of the frame, as described with reference to Figs. 2 and 3 and Figs. 10 and 11, the third part of the frame should not be full of information. This will occur more often and faster in subband coding algorithms, i.e. when the entire process of splitting subband signals and then quantizing samples in different subbands is improved. In particular, this allows information to be transmitted with a smaller number of bits, i.e. an average number per sample. The unused portion of the third portion of the frame may be used to send additional information. In the first part of the FD1 frame in Fig. 10, this is taken into account by determining the future use of bit b23. Normally this bit is 0, as shown in Table 8.

If an additional signal is placed in the third part of the FD3 frame, then the b23 bit of future use in the first part of the frame will be 1 (Fig. 10). When reading the first part of the FD1 frame, this allows the receiver to recognize the frame containing additional information. The allocation and scale factor information (Fig. 12) notifies the receiver that only part of the third part of the FD3 frame, means FD4 in Fig. 12, contains quantized samples of subband signals. The remaining part, designated FD5 in Fig. 12, now contains additional information. The first bit in this part of the FD5 frame was called the INF extension bit. EXPANDED. These bits indicate a type of additional information, which may be e.g. an additional audio channel, e.g. for transmission of a second stereo channel. Another possibility is to use these two additional acoustic channels to realize ambient sound together with the subband acoustic signals in the FD4 frame part. In this case, the front-back information required for ambient sound may be included in part of the FD5 frame. In the part marked FD6

167 271 portions of the FD5 frame, the allocation information, scale factors and sample can be placed, and the order of the allocation words and scale factors can then be similar to the order described with reference to Figures 2 and 3 and Figures 10 and 11.

When transmitting ambient sound, straight receivers can simply decode stereo audio information in portions of the FD2 and FD3 frames, excluding portions of the FD5 frame. More sophisticated receivers are able to reproduce ambient sound information and also use for this purpose information from part of the FD5 frame.

The information extension bits may also indicate that the information in the FD6 frame portion refers to text, for example in the form of ASCII code characters. You may even consider entering video or image information into a portion of the FD6 frame, and said information will be characterized by the information extension bits.

167 271

<img file="PL167271B1_D0002.tif" />

<td rowspan="2">1 SF I. α | &lt;</td><td>| X samples I, a (y bits / p ^ ·) |</td>

<td></td>

<td>1 SF Km 1</td><td>| x samples X, 6i () btt6H / fi '&amp;') |</td>

<td colspan="2">| SF I n |</td>

<td colspan="2">"'I« «*** B (x^bl'V_proUf)</td>

<td>SFI.in</td><td>| «Samples of Im (ybiłiH / pniblta)</td>

<td>1 SF Β 1</td><td></td>

<td></td><td>| x samples K.mly balls / sample)</td>

8 discloses

167 271

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FIG.9

167 271

<td>1 1 1 1 1 1 Ί 1 1 V 1 1 1 1 I at S76N. SVNĆHR._bMl. it .itx. . and . . and</td><td> 5½</td><td>-r ~ - F » —1—.</td><td>Fu »23</td><td>”1 &lt;1 — r — and —1 — Γ — Ι INF. FORMAT Μ. “Τ» »</td>

Figure 10

<td>. tm</td><td>pRiebja. - 1</td><td>c</td><td> %</td><td>EHFAl ^</td>

Figure 11

<td>INF SYNCNft. AND</td><td>1 W and. INF.</td><td>wsr!</td><td>FLEXIBLE! ^INF· !</td><td>οοοατκομτ</td><td>EMPTY !</td>

<td>1 SYSTEM AND</td><td>AdMACJI</td><td>n-1</td><td></td><td>SIGMAt</td><td>cloakroom}</td>

l-FD 6

FD 4

12 is an

<img file="PL167271B1_D0004.tif" />

167 271

SGN

<img file="PL167271B1_D0005.tif" />

<img file="PL167271B1_D0006.tif" />

<td> ♦ 1 &lt;</td><td> 0 75</td><td> 011</td>

<td> 0 71</td><td> 0 50</td><td>oio</td>

<td> 0 42</td><td> 0 25</td><td> 001</td>

<td> 0 14</td><td> 0</td><td> 000</td>

<td> - 0 14</td><td> - 0 25</td><td> 111</td>

<td> - 0 42</td><td> - 0.50</td><td> 110</td>

<td> - 0 71</td><td> • - 0 75</td><td> 101</td>

<td> - 1</td><td> - 1</td><td> 100</td>

<td>(and)</td><td>(B)</td><td>(C)</td>

HO

101

100 he

010

001 · "FIG. 14 (d)

<td></td><td></td><td> 8*</td><td> 8*</td><td></td>

<td> 110</td><td> 010</td><td> 0 50</td><td> 0 857</td><td> ♦ 1</td>

<td> 101</td><td> 001</td><td> 0.25</td><td> 0 571</td><td> 0.71</td>

<td> 100</td><td> 000</td><td> 0 00</td><td> 0.287</td><td> 0 42</td>

<td> 011</td><td> 111</td><td> ' - 0 25</td><td> 0.00</td><td> • 0.14</td>

<td> 010</td><td> 110</td><td> - 0 50</td><td> - 0 287</td><td> - 0.14</td>

<td> 001</td><td> 101</td><td> - 0.75</td><td> - 0.571</td><td> • - 0.42</td>

<td>000 (and)</td><td>100 (B)</td><td>- 1 00 (c)</td><td>- 0 857 (D)</td><td> - 0.71</td>

Figure 15

167 271

<td></td><td>J frame</td><td>FRAME j * 1</td><td></td>

<td></td><td></td><td></td><td></td>

<td></td><td>ip 1</td><td>ip 2</td><td>ip 3</td><td></td><td></td><td></td><td></td>

<td colspan="3"></td><td></td><td colspan="4"></td>

<td>because</td><td>b</td><td>bt</td><td></td><td></td><td></td>

--t bn-1

FIG.1

<td rowspan="2"></td><td>F01</td><td>F02</td><td>FD3</td>

<td>INK. SVNCKR 1 WiTSN.</td><td>INK. HMWCJI</td><td></td>

<td colspan="4">IP1 IPP¹ IPP¹FIG.2</td>

<td>• 1 lily 1 · - | —1, | | | J b₀ SYNCHC. _bj5* i *&gt; iiai, A, ι li * ii</td><td>—1 1 1 1 1 1 1. HEAD OF STZZŁUM.^band 1 1 1 1 1 ł &lt; </td><td>—I —— and — r — i — i — i— INF RBmATU b₂ł frames bj]</td>

FIG. 3

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FIG.4

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