SU1174971A1 - Method of recording-reproducing digital information signals - Google Patents

Abstract

METHOD FOR RECORDING-REPRODUCTION OF DIGITAL INFORMATION SIGNALS by delaying the recording of a sequence of digital information signals for a time longer than the maximum duration of group failures, and recording bits of a sequence of signals of digital information with pulses of different polarity for different values of recorded bits and different duration depending on the result of the match or mismatch of each bit of the information sequence with one of the bits of the delayed sequence; restoring from the reproduction signals a sequence of reproduced signals of digital information, delaying it by time exceeding the maximum duration of group failures, generating distorted signals at the site — signals of failures and generating an output information sequence that differs in that in order to increase the fidelity of recording-reproduction write every bit of digital information signals with pulses of different polarity depending on the result of a match or mismatch bits of the information sequence, one of which is ahead, and the other is lagging behind the recorded bit of information for a time interval not less than the maximum duration of group failures, and during playback, two additional pulse sequences are formed, corresponding to signals of different durations of each of the two related and adjacent reproduce (with the help of the luminous signal of the sequences, after which, for each signal, a failure, in, leading or lagging behind the signals of a fault for a time interval not less than the maximum duration of group failures, and for each information signal leading or lagging behind the signal of a failure for a time interval not less than twice the maximum duration of group failures, a high | initial information sequence.

Description

The invention relates to the field of accumulation of digital information, in particular to methods for recording and reproducing a binary code:

The purpose of the invention is to increase the fidelity of recording-reproduction.

FIG. 1 shows a block diagram of an apparatus for carrying out the method; in fig. 2 - timing diagrams explaining the method.

The device (Fig. 1) comprises a block 1 of the input sequence delay connected in a certain way, a shaper 2 write pulses, a recording unit 3, a control unit 4 comprising a clock pulse generator 5 and a shaper 6 clock pulses, a playback unit 7, a decryption unit 8 consisting of the information sequence 9, the failure signal generator 10, the signal generator 11 of two additional pulse sequences, and the correction signal generator 12, the shaping unit 13 and the output delay one sequence.

When recording, the original sequence (Fig. 2a) is fed to the input of block 1, in which it is delayed by the time ts.an. , exceeding twice the maximum duration of group failures, conditionally accepted here equal to three bit periods. In shaper 2, for each bit of the delayed sequence, a pulse of one polarity is formed, for example, positive, if the bit value is "1" and the other is if the signal is "O", as well as one duration, such as small, if the value of two adjacent bits, with the given signal, are placed, and of a different duration, for example, greater, if they are the same. The positive pulses of short duration (Fig. 26) correspond to single bits and unequal values of the two bits associated with them, separated from them to the left and right by three periods. Positive pulses of longer duration correspond to single bits and the same values of the corresponding bits associated with them. Negative pulses correspond to zero bits, their duration is set similarly. The pulse sequence thus formed is fed to the recording unit 3 and recorded on a magnetic medium.

From the output of the playback unit 7, the amplified sequence of the form of FIG. 2b (distorted signals are conventionally shown shaded) enters the shaper of 6 clock pulses and shapers 9-11. In the imaging unit 9 of the signals of the form of FIG. 2b, using a sync signal from the imager b, depending on polarity, form an information sequence (Fig. 2d) in which rectangular pulses of normalized amplitude and duration correspond to single bits, and the absence of such pulses — zero bits (with single charts, single error signals are noted ). In the imaging unit 10, signals are generated in the event of a loss or distortion of the reproduced signals (Fig. 2d), and in the imaging unit 11, depending on the duration of the playback signals (i.e., a combination of adjacent characters), the signals of the form of Figs. 2e, w. Using these signals in the imaging unit 12, the correction signals are generated (shown in Fig. 2e). In block 13, the correction signals are included in the output information sequence on the ground of the distorted single playback signals.

5B of the proposed method, each information signal depends on the two preceding signals, two adjacent to it and two subsequent signals. This ensures that all failures (including those that are uncorrectable in a known manner) are automatically corrected, with the exception of average failures in sequences of three or more of the following failures. The probability of uncorrectable information distortions in the proposed method is about, i.e. 1 / Pc5 times less than in the known method. In addition, each reproduced signal in the proposed method is monitored three times: by the two preceding and two subsequent signals. It provides at times more

d the correctness of the corrected information in comparison with the known method. Since the occurrence of three or more of the following failures in the chain of dependent signals is always corrected by the last two, the proposed method provides a smaller amount of poor-quality information.

For example, the zero value of the first failed signal (the seventh period of the reproduced sequence) is restored by the single value of the signal in the first period and by the signal of the additional

the sequences (fig. 2g) in the fourth period, the unit value of the third failure period (fig. 2d) (the ninth period of the reproduced sequence) is restored by the zero value of the signals in the third period and the signal of the additional sequence in the scatter period, the unit value of the failed signal in The 15th period is reconstructed twice: by a single signal in the 21st period and by the signal of the additional sequence (phi) -. 2e) in the 18th period, as well as by the recovered unit value in the ninth period and the characteristic of the sequence of FIG. 2nd in the 12th period. Consequently, the correction of double failures of maximum multiplicity in dependent blocks of information is achieved, the double correction of each

5 single failure maximum frequency, double control of each faultless signal.

Claims (1)

METHOD FOR RECORDING-PLAYING DIGITAL INFORMATION SIGNALS by delaying before recording a sequence of digital information signals for a time exceeding the maximum duration of group failures, and recording bits of a sequence of digital information signals with pulses of different polarity for different values of the recorded bits and different durations depending on the result of the coincidence or mismatch of each bits of the information sequence with one of the bits of the delayed sequence, form from signals of reproducing a sequence of reproduced signals of digital information, delaying it for a time exceeding the maximum duration of group failures, forming in place of distorted or dropped out signals — fault signals and generating an output information sequence, characterized in that, in order to increase the fidelity of the recording, reproduction, record each bit of digital information signals with pulses of different polarity depending on the result of the coincidence or mismatch of two bits information sequence, one of which is ahead and the other lags relative to the recorded bit of information by an interval of time not less than the maximum duration of group failures, and when playing back, two additional sequences of pulses are formed corresponding to ~ signals of different durations of each of § two connected and adjacent to the reproduced signal sequences, after which for each signal of failure, for each signal of two additional sequences of pulses, leading ahead lags behind the signal at the failure time interval not less than the maximum duration failures group, and each information signal leading or lagging behind the signal at the failure time interval not less than twice the maximum duration of group failures form output information sequence. SU, .1174971