SU964999A1 - Convolution code threshold decoder - Google Patents

Description

The invention relates to communication technology and is intended for use in apparatus for transmitting discrete information.

A convolutional code decoder is known, comprising a series-connected encoder, a syndrome analyzer, a first threshold detector, a first correction inhibit block, the output of which is connected to the corresponding inputs of a syndrome analyzer, and an error packet detection unit and a second threshold detector and a second correction inhibit block in series, an output which is connected to the first input of the error corrector [1]. .

However, the known threshold decoder has insufficient noise immunity due to the effect of error propagation.

The purpose of the invention is to increase noise immunity.

To do this, in the threshold convolutional decoder containing a serially connected encoder, a syndrome analyzer, a first threshold detector, a first correction inhibit block, the output of which is connected to the corresponding inputs of the syndrome analyzer, as well as an error packet detection unit and a second threshold detector in series, second a correction inhibit block, the output of which is connected to the first input of the error corrector, a delay block and an additional syndrome analyzer are connected in series, as well e is a correction control unit, a control signal delay unit and an information sequence delay unit, the output of the error correction detection unit being connected to the output of the correction correction prohibition unit and the output of the error package detection unit being connected to the input of the correction control unit, the output of which is connected to the second input of the first the correction inhibit block directly and through the control signal delay block to the second input of the second correction inhibit block, and the output of the second correction inhibit block is connected to the corresponding the corresponding inputs of the additional analyzer of the syndrome, while the second input of the error corrector is connected to the output of the encoder through the delay unit of the information sequence, and the inputs of the encoder are combined with the corresponding inputs of the delay unit.

The drawing shows a structural diagram of a threshold decoder convolutional code.

prostrate, gives a signal to the control unit 7 of the correction prohibition blocks 5 on the prohibition of false correction in the analyzer 2 syndrome and corrector 4 errors.

The decoder contains encoder 1, analyzer 5 mash 2-1 syndrome, additional analyzer 2-2 syndrome, the first threshold detector 3-1, the second threshold detector 3-2, corrector 4 errors, the first block 5-1 prohibit correction, the second block 5-2 inhibit correlation, block 6 detection of error packets, block 7 control correction, block 8 delay, block 9 delay information sequence, block 10 delay control signals.

Decoder: works as follows.

.When there is no error in the discrete channel, then encoder 1 generates at the test outputs sequences identical to ²⁰ ./ sequences to the test sequences at the output of the discrete channel. In this case, the input circuits of the main and additional analyzer 2 syndrome form sequences of zeros. The threshold detectors of 3 thresholds do not exceed and correction does not occur. If errors have occurred in the code sequence with a multiplicity less than the correcting ability of the code, then 30 units are formed in the test sequences that enter the analyzer 2 of the syndrome in such a way that they first arrive at the main analyzer 2-1 of the syndrome and only after 35 times equal to the duration ^ - information symbols, through blocks 8-1 8> 4-delays of test sequences in an additional analyzer of 2-2 syndrome. In this case, from the outputs to the threshold detectors 3, single correction symbols appear, the syndrome analyzers 2 are corrected, clearing the syndrome of the multiplied error, and the distorted information symbols of the code combination are corrected, while the correction control unit 7 of the correction prohibition blocks 5 does not give a control signal to prohibit correction .

“L correction

To coordinate the moment of distorted information symbols of the code combination in the error corrector 4, a signal delay unit 10 is used (control blocks 5 of the correction prohibition, 'delaying the corresponding signals by ⁵⁵ K-information symbol durations.

When errors are multiplied from the output of the threshold detector 3-2, single correction signals are sent to the error packet detection unit 6, which, having counted 60 more than the specified number of units, Thus, by disconnecting the correction chains for a duration equal to the Kinformation symbols, we completely change the state of the registers of the analyzer 2 syndrome, the analyzers are thereby cleaned of the multiplied error, and there is no false correction of information symbols. As a result, the noise immunity of the decoder is increased due to the prevention of error propagation.

Claims (1)

the corresponding inputs of the delay unit. The drawing shows a block diagram of the convolutional code threshold decoder, the Decoder contains encoder 1, syndrome analyzer 2-1, additional syndrome analyzer 2-2, first threshold detector 3-1, second threshold detector 3-2, corrector 4 errors, first block 5 -1 a correction prohibition, a second correction prohibition block 5-2, a packet error detection block b, a correction control block 7, a delay block 8, an information sequence delay block 9, a control signal delay block 10. Decoder; works as follows. . When there are no errors in the discrete channel, then encoder 1 forms identical sequence of test sequences at the output of the discrete channel on the test outputs. In this case, the input circuits of the main and additional analyzers of the syndrome form zero sequences. Threshold detectors of 3 thresholds do not exceed and the correction does not occur. If errors occurred in the code sequence with the multiplicity of the smaller corrective capacity of the code, then in the test sequences units are formed that enter the analyzers 2 of the syndrome in such a way that they first enter the main analyzer 2-1 of the syndrome and only after the time equal to the duration of the K-information characters through blocks 8-1 8 -4-delay check sequences in the additional analyzer 2-2 syndrome. At the same time, single correction symbols appear from the outputs of the threshold detectors 3, npq: gcxodit correction of the syndrome analyzers 2, clearing the syndrome from the multiplied error, and the correction of the distorted information symbols of the code combination, while the correction correction block 5 does not generate a control signal correction prohibition To reconcile the moment of correction of the distorted information symbols of a code combination in the 4 error corrector, a signal delay block 10 (control of the correction prohibition blocks 5, Keeping the corresponding signals for the duration of K-information symbols When errors multiply from the output of the threshold detector 3-2, single correction signals are sent to the error packet detection unit 6, which, having counted more than a specified number of units, gives a signal to the prohibition correction block 5 false correction in syndrome analyzers 2 and error corrector 4. Thus, by disconnecting the correction circuit for a duration equal to the Information Symbols, we completely change the state of the registers to the analyzer 2 syndrome, thereby cleaned analyzers from the expanded errors and there is no false correction information symbols. As a result, the robustness of the decoder is increased due to the prevention of multiplication; Research Institute of errors. The claims of a convolutional code threshold decoder containing a serially connected encoder, a syndrome analyzer, a first threshold detector, a first correction inhibitor block, the output of which is connected to the corresponding inputs of the syndrome analyzer, as well as an error packet detection unit and a second correction inhibitor block The output of which is connected to the first input of the error corrector, characterized in that, in order to improve the noise immunity, a successor is entered but the connected delay block and additional syndrome analyzer, as well as the correction control block, the control signal delay block and the Delay block of the information sequence, moreover, are connected to the input of the packet error detection block, the output of the first correction inhibit block, and the output of the error packet detection block are connected correction control, the output of which is connected to the second input of the first correction inhibit block, directly and through the control signal delay block to the second GNUMP of the second block Single prohibition correction, and the output of the second correction prohibition unit connected to the respective inputs of the additional syndrome analyzer, the input error corrector connected to the output of the encoder through a delay unit sequence information, and the encoder inputs are combined with corresponding inputs Zsscherzhki block. Sources of information taken into account in the examination 1. USSR author's certificate 586571, cl. H 04 L 1/10, 1976 (prototype).