Method and circuit for the transmitting, recording, and/or reproducing of wide-band signals

El.-Nr. 1887/79 28.2.1979 EE / PLI / Klm / Hö

ROBERT BOSCH GMBH, 7OOO Stuttgart 1

Method and circuit arrangement for transmitting or recording and / or reproducing broadband signals

State of the art

The invention is based on a method according to the preamble of the main claim. From DE-PS 969 818 a method for transmitting and recording signals comprising a wide frequency band is already known. In the known method is

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decomposes the signal into several smaller frequency range signals and transmits or records them independently. To obtain the plurality of signals corresponding to the intended number of transmission channels, instantaneous values ​​of the output signal are blanked out with the aid of phase-shifted pulse trains. For the time-correct assembling of the intermediate signals transmitted or recorded in the individual channels to the original signal, the transmission of the sampling frequency is required.

The known method can not be used for the transmission or recording of frequency-modulated output signals since the instantaneous values ​​of the output signal differ only in frequency but not in amplitude. Although the carrier-frequency transmission of the intermediate signals is conceivable in principle and also leads to a reduction in the bandwidth requirement of the individual transmission channels for the intermediate signals in relation to the required bandwidth for the frequency-modulated transmission of the output signal, but prepare the balance of the then necessary plurality of modulators and the phase errors occurring when put together the intermediate signals to the original signal extraordinary difficulties. In particular, in the magnetic storage of the intermediate signals in multiple tracks of a magnetic tape inaccuracies of the tape run to intolerable phase errors zifischen the individual channels, which complicate the proper demodulation of Zwischensif ^ nale and their gapless Zudemnnetzen.

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ORIGINAL

Rl.-Nr. 1887/79

From DE-AS 22 37 255 another system is known with which the bandwidth of a video signal recording and playback device is reduced. For this purpose, the video signal, dos contains any information, decomposed into a number of signals. These signals are recorded in multiple channels in memory circuits. The video signal is modulated to a lower frequency range by outputting or reading the signals in a longer period than the write-back. In the reproduction, the recorded signals are in turn written in memory circuits, to be outputted again in a shorter period of time than when writing. This restores the original time and thus the original video signal.

Advantages of the invention

The inventive method with the characterizing features of the main claim has the advantage that for the carrier-frequency transmission of the sub-signals, the number of required modulators and demodulators does not depend on the number of transmission channels. A further advantage is that the adjustment of the individual transmission channels is easier to carry out as a result of the omission of numerous modulators and demodulators.

In a television signal, the signal sections subjected to the time transformation advantageously correspond to a line length. The switching operations are preferably placed in the blanking intervals.

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BATH ORIGINAL

IiI. -Kr. 1ÖÖ7 / V9

By the measures listed in. The Unteransprüclien advantageous refinements and improvements of the main claim method are possible. Particularly passing by is that transmission errors, in particular amplitude errors of the transmission chain, without influence remain on the level of the demodulated video signal, regardless of which transmission channel, the signal is removed immediately. The problem of time and phase accurate composing eggs part signals to the original signal is thus easier to deal with.

According to another embodiment of the invention, it is also advantageous to convert the color information into a frequency band which is largely free from FM sidebands and to add it in supported form before the division and time transformation to the FM-modulated BAS signal and analogue back to the demodulated BAS after the inverse transformation. Add signal. The elements for time transformation can thus be used jointly and simultaneously for both signal components (luminance, chrominance).

Advantageously, the separation takes place only after the time error compensation carried out for both signal components.

drawing

Embodiments of the invention are illustrated in the drawings and explained in more detail in the following description. Show it:

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- £ Rl.-Nr. 1887/79

Fig. 1 shows schematically the block diagram of a device for carrier-frequency recording and reproducing a video signal in a plurality of adjacent tracks;

FIG. 2 shows a schematic block diagram of the device according to the invention for carrier-frequency recording and reproduction of a video signal in several adjacent tracks; FIG.

Fig. 3 is a schematic block diagram of another embodiment of the device according to the invention.

Description of the invention

As is apparent from Fig. 1, which represents the prior art known to the Applicant, fractions of the television signal are usually subjected to a time transformation (time stretching) and the time-transformed signal portions are simultaneously assigned to individual tracks, modulated onto a carrier frequency and recorded. Because of the modulation after division and time transformation, as many modulators are required as there are channels (tracks). Accordingly, as many demodulators as channels (tracks) are required. However, ensuring equal transmission characteristics for all channels and channel-wise time-transformation of video signals is difficult and time-consuming, and success is not always given.

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BATH ORIGINAL

Rl.-Nr. 1887/79

In the method according to the invention, for which the Pig. As an exemplary embodiment represents a Üehaltungsanordnung v / ird the incoming video signal 10 is supplied to the input of a modulator 11 and modulated in the modulator 11 of a carrier frequency in a known manner. The frequency-modulated signal appearing at the output of the modulator 11 is distributed sequentially to the intended η channels in accordance with the position of the switches 12.1, 12.2... Timing signal or fraction or a multiple thereof are used.

In the time stretchers 13.1, 13-2 ».» ... 1 $ .η, the signal sections of the individual channels (tracks) are stretched to η times, thereby simultaneously undergoing a frequency transformation by a factor of -. These stretched, frequenztransformxerten signal sections can be recorded by means of the converter means 14.1, 14.2 .. .. ".. .. 14.η in η adjacent tracks on a (not shown) magnetic tape.

For the reproduction of the time-stretched signal sections stored on the magnetic tape, these are read out by the converters 14.1, 14.2,... 14 .eta and fed to the time-transformation elements 15 × 1 × 15 × 2... 15 × η for time-lightening , The signal sections present at the output of the time-delay elements 15-1ί 15.2 15 · η

again correspond to the pre-time expansion

Signal sections at the output of the switches 12.1, 12.2

12.η and can thus be composed by a same set of switches 16.1, 16.2 ...... 16.η to the continuous frequency-modulated signal. This composite signal passes through the demodulator 17th

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BATH ORIGINAL

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and appears at its output as a demodulated original video signal.

The embodiment of the invention gem. Fig. 3 contains z. T. the same circuit elements as the after the pig. 2, which perform the same functions and are therefore provided with the same reference numerals. In addition, the circuit arrangement according to FIG. 3 has a converter 18 for converting the carrier chrominance signal from, for example, 4.4 MHz to 0.562 MHz. This converted chrominance signal is added in the adder 19 to the frequency-modulated BAS signal.

Similarly, after being transferred from the FM-modulated signal, the color component at 0.562 MHz is filtered out, converted back to 4.43 MHz in converter 20 and combined to form the complete CVBS signal by means of quadrant 21.

With the circuit arrangement according to the invention, therefore, a method for storing frequency-modulated signals in a plurality of tracks or for transmission in a plurality of channels can be carried out, in which the transmission characteristics of the individual channels can be kept more easily the same.

030037/0192

BATH ORIGINAL

El-Mr »1887/79

28.2.-1979 ΙΈ / PLI / Klm / HÖ

ROBERT BOSCH GMBH, 7OOQ Stuttgart 1

Summary

The invention relates to a method and a circuit arrangement for transmitting or storing a broadband signal in a plurality of narrow-band channels, in which the frequency modulation and demodulation takes place in the broadband channel. By avoiding a multiplicity of modulators and demodulators in the individual transmission channels, the uniformity of the transmission characteristics is achieved of the overall system improved.

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