Method and device for transmitting digital telemetry signals in a digital data flow.

p0001The invention relates to a method and a device for retransmitting digital telemetry characters over a digital data line according to the preamble of the independent claims.

p0002Under telemetry transmission of the measured values ​​of electric lines is understood for the purpose of remote reading of measuring instruments in the strict sense. Herein is intended under telemetry general the relatively slow transmission of digital signals for the purpose of controlling, monitoring, etc. to be understood, wherein the transmission takes place via a relatively faster transmission path, which is provided primarily for the useful signals of another kind.

p0003A first known method of transmission of telemetry signals over a digital transmission line is that the constant itself amplitudes of the digital information signals for the telemetry signals are amplitude modulated. The given herein mixing of digital and analog technology is complicated and prone to failure.

p0004a method of transmission of telemetry signals is known from FR-A-2529415, which operates purely digitally. In this method, the primary data is transmitted using the trivalent HDB3 or the modified CMI codes (MCMI). In the latter, there are permitted blocks 00, 11 and 01 and prohibited blocks 10, which primarily serve for error detection. The method is now based on that for the transmission of telemetry signals each a permitted block 01 is replaced by a prohibited block 10, which can be detected and corrected at the receiving end.

p0005The disadvantage of this method is that the interchangeable blocks 01 do not regularly occur in the flow of transmission link and therefore there is no full transparency for the to be transmitted telemetry signals. Next is the transfer of the method to a Uebetragungsstrecke, on the pure CMI code is used, is not possible because the CMI code very long sequences without allowing blocks may occur 01.

p0006The object of the invention is to show a telemetry transmission via a data line, on the pure CMI code is used. This should be possible full recoverability of the primary data signal and possible delay-free, full-time transmission of telemetry signals. The required configuration should be simple and operate at very high transmission rate, especially at 140 Mbit / s. The solution of this problem is given by the characterizing part of the independent claims. The dependent claims define embodiments of the invention.

p0007The inventive method of telemetry transmission is simple and meets the requirements set make demands. The circuit complexity is well realized very low and even with the required high transmission rates.

p0008In the following the invention will be described in greater detail, for example, based on twelve figures. Show it:<ul><li>Fig. 1 - basic block diagram of a digital transmission link with additional telemetry</li><li>Fig 2 -. Examples of a data signal in which are inserted according to different rules telemetry blocks</li><li>Fig. 3 Examples for the transmission of various telemetry signals</li><li>Fig. 4 - Block diagram of a first telemetry insertion circuit</li><li>Fig. 5 - Block diagram of a second telemetry insertion circuit</li><li>Fig. 6 - the second telemetry insertion circuit associated logic table</li><li>Fig. 7 - Block diagram of a third telemetry insertion circuit</li><li>Fig. 8 - the third telemetry insertion circuit associated logic table </li><li>Fig. 9 - Block diagram of a Telemetrieerkennungs- and Datensignalregenerator circuit</li><li>10 to 12 -. Logic tables that are associated with the circuit according to Fig. 9.</li></ul>

p0009FIG. 1 shows a basic block diagram of a transmission route for primary data signals D and telemetry signals S. The track comprises an incoming data line 20, a telemetry transmitter 22, a telemetry insertion circuit 23, an output amplifier 24, a directional, digital transmission line 30, an input amplifier 35, a Telemetrieerkennungs- and Datensignalregenerator circuit 36, to which the outgoing data line 40 is connected as well as a telemetry receiver 37th

p0010The incoming 20 and outgoing line 40 form short connections to other electronic devices in general. In contrast, the transmission line 30 is preferably constructed as optical or fiber optic line of considerable length.

p0011The code used for the primary data transmission is the CMI code, defined by the international standard CCITT Fascicle III. 3 -. Rec G. 703 is standardized for a frequency of approximately 140 Mbit / s. (CMI coded mark inversion).

p0012The CMI code transmits the bits of the primary data signal D in the form of permitted blocks E from two bits according to the following mapping rule <tables id="tabl0001" num="0001"><table frame="topbot"><tgroup cols="2" colsep="1" rowsep="0"><colspec colnum="1" colname="col1" colwidth="78.75mm" /><colspec colnum="2" colname="col2" colwidth="78.75mm" /><thead valign="top"><row><entry namest="col1" nameend="col1" align="center">primary data signal</entry><entry namest="col2" nameend="col2" align="center">CMI code</entry></row></thead><tbody valign="top"><row><entry namest="col1" nameend="col1" align="right">0</entry><entry namest="col2" nameend="col2" align="left">01</entry></row><row><entry namest="col1" nameend="col1" align="right">1</entry><entry namest="col2" nameend="col2" align="left">00 and 11 alternately</entry></row></tbody></tgroup></table></tables>

p0013When CMI code, there are thus three types of permitted blocks E, namely 01, 00 and 11. Blocks 10 are prohibited against (prohibited block V) and show primarily on the receiving end of a transmission link transmission errors. The requirement that the blocks with two identical bits (00,11) code according to alternate each is referred to as Alternating rule.

p0014The telemetry signal S has a frequency f_S on which small compared to the frequency f_D the data signal D is, for example, a thousand times smaller. This low frequency f_S will now each a telemetry mark t as the smallest unit of the telemetry signal S transmitted. To this end, each a permitted block E replaced regardless of the time and regardless of the variety of permitted blocks E in the telemetry insertion circuit 23 by a telemetry block T or several allowed Blocks E through a corresponding number of telemetry blocks T. In the Telemetrieerkennungs- and Datensignalregenerator circuit 36 ​​via the transmission line 30 incoming telemetry blocks T are detected. The circuit 36 ​​outputs for each telemetry block T a signal to the telemetry receiver 37 which therefrom forms the telemetry signal S and delivering on its output. The telemetry receiver 37 further distinguishes telemetry blocks T and error blocks, the foul occur due to transmission errors. This will, however, not discussed at this point.

p0015The Telemetrieerkennungs- and Datensignalregenerator circuit 36 refund continues every telemetry block T by the "correct" allowable block E and brings with it the data signal in order. In this way, any telemetry signal S via the conduit 30 is thus in addition at any time the respective data signal D transferable. This means that there is full transparency of the transmission link for both the data signal D as well as the telemetry signal S.

p0016Before replacing the allowable Blocks E through telemetry blocks T following general mapping rules apply: - Each variety of permitted blocks E is associated with a specific type of telemetry blocks T. - Certain types of telemetry blocks T agree with certain types of permitted blocks E. - Each telemetry block T, which replaces a permitted block E, violates a code rule of the CMI code or is a prohibited block V.

p0017There are several ways to implement this general mapping rules specifically.

Possibility A:

p0018Any permitted block E is replaced by a telemetry block T, whose bits are compared to the bits of the replaced block E are both inverted. This means that the E-blocks 01, 00, 11 are replaced by T-blocks 10, 11 and 00th There is no further action.

Option B:

p0019Any permitted block E is replaced by a telemetry block T, whose bits are compared to the bits of the replaced block E are both inverted. This means that the E-blocks 01, 00, 11 are replaced by T-blocks 10, 11 and 00th If a block with two similar bits (00, 11) is replaced, then are inverted with respect to their bits as a further measure all subsequent blocks with two identical bits (00,11).

Option C:

p0020Permitted blocks E with two equal bits (00, 11) are replaced by a prohibited block V (10). Permitted blocks E with two dissimilar bits (01) are replaced by a block with two identical bits (00, 11), in such a way that the Alternating rule of CMI code is violated.

p0021To illustrate these three possibilities A, B, C, Fig. 2 shows an example of a data signal D, in the at different times depending on a telemetry block T is inserted. In the top row, the sequential number of consecutive blocks of the data signal D (third row) and the these blocks assigned primary data signal (second line) is indicated. In the following lines, the data signal D is respectively repeated progressively each other E-block is replaced by a telemetry block T first in accordance with the Option A and then in accordance with the options B and C. So in line A1 of the first block is replaced, in line A2 of the second, etc. The same applies to the lines B and C.

p0022In Example A in accordance with that option A every telemetry block T is obtained from the replacing permitted blocks E by inverting both bits. This is a very simple process, which is easily performed on the transmitting side using an exclusive OR gate (EXOR).

p0023On the receiver side, however, arises in the way A complication for telemetry blocks T with two similar bits (00, 11). These namely occurs in each case a second violation of Alternating rule of CMI code as soon as the respective next, not inverted E-block with two identical bits occur. This can be done immediately after following the respective telemetry block T or significantly delayed, which is disturbing.

p0024In Example B according to the way the B T-blocks are also obtained from the E-blocks by inverting the bits. Next, however, a logic necessary, the E-blocks with two equal bits (00, 11) of E-blocks differs with two dissimilar bits (01), and, if a block with the same bits (00, 11) is inverted, all subsequent blocks with two equal bits (00, 11) also inverted. This has the advantage that in this way the described occurrence of the respective second code violation of the Alternating rule of the CMI code is prevented.

p0025In Example C according to the third option C also occurs each on only one code violation, either by a single prohibited block V or by a single breach of Alternating rule. Again therefore eliminates the respective second code violation for a telemetry block T.

p0026Because any time, any block E of the data signal D for the transmission of telemetry character t can be replaced, there are almost unlimited possibilities for the transmission of telemetry signal S. Fig. 3 shows examples for this purpose. In case I will each of a divalent telemetry signal S with the telemetry mark t0 and t1 in accordance with the logic levels 0 and 1 - as previously assumed implicitly - but the sign t1 transmitted as telemetry block T. The mark t0 is not explicitly transmitted, but implicitly because of the time clock of the telemetry signal S. This means that in the flow of permitted blocks E of the data signals D telemetry characters t0 is not primarily recognizable and the telemetry characters t1 is represented by a single telemetry block T.

p0027t₀ Other options for the transmission of two or three different telemetry mark, t₁, t₂ exist as a fact that according to Case II associated respectively, two or three telemetry blocks T to be transmitted, or that two telemetry blocks T are under Case III transferred, but with associated varying time interval, ie, a variable number of intermediate blocks allowed E. another option case IV consists, for example, that three blocks e and T are jointly understood as a code word.

p0028In the following detailed circuit arrangements of the telemetry insertion circuit 23 as well as the Telemetrieerkennungs- and Datensignalregenerator circuit 36 ​​will now be described with reference to further figures, which are assigned to the possibility described A, B and C of the general principle. Possibility C has over the other options regarding conduct while transmission errors on some advantages and is therefore preferred. On the other hand, allows the possibility of a very simple implementation of B, if the data signal D is not present in CMI-coded form or to be dispensed.

p0029Fig. 4 shows the block diagram of a first telemetry insertion circuit 23A, corresponding to said opportunity A. The circuit 23A includes a Taktableiteeinheit 42, an inverter unit 52 and a telemetry pulse unit 54th

p0030The blocks E of the data signal D achieve the telemetry insertion circuit 23 through the line 20, the telemetry character t on the input 55. The Taktableiteeinheit 42 forms a known function block, which regenerates the bit clock BT and block clock signal DT of the data signal D and via its outputs the other functional units provides.

p0031The telemetry pulse unit 54 are respectively when a telemetry mark t is to be transmitted, a telemetry pulse on its output 56 from which is synchronized with an arbitrary block of the data signal D. inverts the inverter unit 52, then the two bits of the respective block E of the data signal D, and sends the thus-modified data signal D to the transmission line 30 from.

p0032Fig. 5 shows the block diagram of a second telemetry insertion circuit 23B, corresponding to said opportunity B. The circuit 23B includes the same as the circuit 23A of FIG. 3 is a Taktableiteeinheit 42, an inverter unit 52 and a telemetry pulse unit 54. In next come a delay unit 44, a scanner unit 46, a memory unit 48 and a logic unit 50.

p0033The delay unit 44 delays the through line 20 incoming data signal D bit to a block length and outputs the delayed data signal D on to the inverter unit 52. The scanning unit 46 scans in phase each from the delay unit 44 located Block E of the data signal D. The respective scanning result is notified to the memory unit 48 and the logic unit 50 via the connecting 47th

p0034The logic unit 50 thus receives via the connection 47 for each block E information on the variety. She continues to receive via connection 49 information from the memory unit 48 on the current content. And it is finally obtained via the connection 56 from the pulse telemetry unit 54 the message, whether the respective permitted block E to be transmitted as telemetry block T on the transmission line 30 or not. The logic unit 50 operates according to the logic table shown in FIG. 6 and controls the inverter unit 52. Once a telemetry block T is to be sent, it prepares the telemetry pulse unit 54 before and are in phase a telemetry pulse from the logic unit 50. This inverted prejudice to the respective block E in the inverter unit 52 to a telemetry block T. Was called E-block is a block with two dissimilar bits (01), so thus ends the process. It was, however, a block E with two equal bits (00, 11), so all subsequent blocks allowed E with two similar bits are inverted subsequently also. (However, this does not affect the information content of the data signal D.) The question of knowing whether to be below a telemetry block T inverted each or not is included in the memory unit 48 and is constantly updated via the interface 47.

p0035Said inverting all subsequent blocks allowed E lasts until a next telemetry mark t by inverting an E-block with two identical bits (00, 11) is transmitted. If this is the case, then a total of double inversion, corresponding to an Nichtinvertierung. This generally means that before a to be emitted, odd (n = 1, 3, 5, 7, ...) or according to any one emitted even-numbered (n = 2, 4, 6 ...) telemetry characters t with two similar bits are all blocks 00 and 11 of the non-inverted data signal D are transmitted via the transmission line 30th By contrast, according to an odd telemetry mark t or basically be transmitted inverted before an even telemetry mark t with two identical bits all the blocks 00 and 11 of the data signal D.

p0036The logic table of FIG. 6 indicates in the first column, if a telemetry mark t is to be sent or not. The second column shows the respective via line 20 incoming allowed Block E of the data signal D. The third column reflects the contents of the memory unit 48 and the fourth column the transmitted to the transmission line 30 block locations. In the memory unit 48 0 means the state before be emitted odd telemetry mark with two identical bits. contrast 1 signifies the state before an even telemetry mark with two identical bits.

p0037Fig. 7 shows the block diagram of a third telemetry insertion circuit 23C corresponding to said opportunity C. This block diagram corresponds largely to that of the circuit 23B.

p0038In the memory unit 48 is stored, what kind of permitted blocks E with two equal bits (00, 11) is in each case occurred last. This means that for each sampled block 00 and 11 respectively 00 and 11 is stored, while each sampled block 01 the memory content of the memory unit 48 unchanged.

p0039The logic unit 50 receives via the connection 47 information about the grade of each output from the delay unit 44 blocks the data signal D via connection 49 information about the sort of the last block with two similar bits (00, 11) and via the connection 56 information if a telemetry mark t is to be sent or not. These three pieces of information to form a respective associated control command that it delivers to the inverter unit 52 via the connecting 51st

p0040Fig. 8 shows the the circuit 23C associated logic table. The first column indicates whether a telemetry mark t is to be sent or not. The second column shows the respective via line 20 incoming block E, the third column the respective old and the fourth column the respective modifications of the memory unit 48. The fifth column specifies finally what kind of block is sent out each of the inverter unit 52nd

p0041Fig. 9 shows the block circuit diagram of a Telemetrieerkennungs- and Datensignalregenerator circuit 36, which corresponds to the possibilities A, B, C above, and thus the counterpart to the telemetry insertion circuits 23A, 238 and 23C is formed. The circuit 36 ​​includes a Taktableiteeinheit 142, a delay unit 144, a scanner unit 146, an inverter unit 152, a memory unit 148 and a logic unit 150th

p0042Fig. 10 shows a first logic table A, corresponding to the first telemetry insertion circuit 23 A. The first column shows the transmission line 30 via the incoming blocks E and T of the data signal D and a possibly superimposed telemetry character t. The second column shows the respective old and the third column the respective modifications of the memory unit 148. The fourth column shows the blocks E of the regenerated data signal D at the output 153 and the fifth column, the telemetry signals t at the output 154 of the circuit 36 ​​at.

p0043The telemetry detection circuit 36 ​​in combination with the logic table A operates as follows: The transmission line 30 on the incoming blocks of the delay unit 144 is supplied and distributed by this delay to the inverter unit 152nd The Taktableiteeinheit 142 regenerates the bit BT and the block clock DT. The scanning unit 146 scans in the block clock signal DT, the blocks in the delay unit 144, and outputs the respective blocks corresponding signals to the memory unit 148 and to the logic unit 150 from. The memory unit 148 memorizes each, what sort of blocks with two equal bits (00, 11) was last scanned. The logic unit 150 detects, in cooperation with the memory unit 148 all the blocks that are either forbidden or violate the Alternating rule of CMI code. For each prohibited block are the logical unit 150 a signal from t at its output 154th For blocks that violate Alternating rule, they are only for the first two of each from a signal t. This can be achieved that in case of Alternierungsverletzung not the current (incorrect) type of blocks with two equal bits (00, 11) but the other is pinned in the memory unit. For both types of code rule violations, the logic unit is further in each case a control command over the connection 151 to the inverter unit 152 are inverted by the respective two bits of the respective sampled block and the respective former allowed Block E of the data signal is restored. The thus completely regenerated data signal D can be tapped at the second output 153 of the telemetry detection circuit 36th

p0044The circuit 36 ​​and the possibility B associated logic table shown in FIG. 11. This is simpler than that which is assigned to the receiver corresponding to the option A (Fig. 10), since for each telemetry mark t as described in each case only one code violation occurs. The logic table corresponding to the option C is shown by FIG. 12. Also this is relatively simple.

p0045The concrete construction of the units described depends on the technology used, and from a practical point. The delay units 44, 144 may be shift registers or may be composed of serially-connected flip-flops, wherein each flip-flop delays the data signal D about a respective bit length.

p0046The scanning units 46, 146, memory units 48, 148 and the logic units 50, 150 are made up of logic gates and flip-flops together so that the corresponding one of the respective logic table conditions are met. The control commands on the links 51 and 151 may consist of two sub-instructions that is selectively inverted or non-inverted form through the series, the first and second bits of the respective block. However, the commands may also block commands are inverted by the bit-parallel, the two bits of each block and / or non-inverted. The Invertiereinheiten 52 and 152 consist of exclusive OR gates (EXOR).

p0047The described, for example, circuit excessive build the telemetry insertion circuits 23A, 23B, 23C and Telemetrieerkennungs- and Datensignalregenerator circuits 36 is relatively simple and also for the required high bit rate of 140 Mbit / s with relatively inexpensive, commercial blocks realized.

p0048The decision whether an item of the Telemetrieerkennungs- and Datensignalregenerator circuit 36 ​​Code violation of a disturbance of the bit stream on the transmission line 30 rises, thus representing an error, or is a telemetry mark t, makes the telemetry receiver 37th He exploited this in statistical terms and time criteria, but what not be described here.

p0049Overall, that a telemetry signal S with the aid of the circuits and methods described in Uebertragungsstrecken on which the CMI-code is used, with little effort, in addition to the primary data signal D transferable. In this case, there is for both the data signal D as well as the telemetry signal S full transparency. This means that no restrictions of time or otherwise exist. In particular, the telemetry signal S may be formed as desired, for example, as divalent or trivalent digital signal with relatively freely selectable switching frequency, as long as its clock rate remains well below that of the data signal D.