SU1304071A1 - Device for decoding play signal of magnetic record - Google Patents

Abstract

The invention relates to magnetic recording and allows for greater fidelity in reproducing information. The trigger 13 and the elements AND-NOT 16 and NOT 15 constitute the delay circuit of the input pulses. Using the flip-flops 14 and 18, the delayed pulses and the input pulses, respectively, generate signals that are fed to the inputs of the phase detector consisting of flip-flops 6 and 7, modulators 4 and 5 modulo two, resistors 2 and 3. At the input of the lower filter 1 frequencies from the phase detector are negative pulses, the duration of which linearly depends on the phase shift between the input signal and the series of pulses of the controlled oscillator 8. The signal from the low-pass filter 1 linearly depends on the mismatch between the input signal and the series pulse controlled oscillator 8. The isolated binary code sequence is formed on the adder input 17 of modulo two and input to the decoder. 3 il. i (L 00 about 4: About

Description

The invention relates to magnetic recording, in particular, devices for decoding a magnetic signal playback signal.

The purpose of the invention is to increase the loyalty of information reproduction.

FIG. 1 shows a functional diagram of the device; in fig. 2 and 3 - time diagrams of his work.

A device for decoding a signal

trigger 13 on the input R (Fig. 1); ts is the modulo two adder delay 4, 5, and 17. The notation in FIG. 3. TV-detection window; At |, At2 - mismatch between the pulses of the generator 8 and information; U is the logical "1" voltage at the output of the elements.

The device works as follows.

The trigger 13 and the elements of the NAND and NOT 16 and 15 are the delayed input circuit

The reproduction of a magnetic recording contains Q pulses for the time t2 (Fig. 26, c). With pomofilter 1 low frequency, connected to the input interconnected one pins of the first and second resistors 2 and 3, other pins connected to the outputs of the first and second adders 4

By triggering the flip-flops 14 and 18, of the delayed and input pulses, respectively, BVNM-type signals are formed, in which each transition from "O to" 1 and from "1 to" O corresponds to the leading edges of pulses

and 5 modulo two, connected via t5 (Fig. 2d, d). The received signals are supplied by the first inputs to the inputs of the phase detector, which are interconnected by the inverse output nepBOi o trigger b and the information input of the second trigger 7 connected by the output to the second input of the second modulo two and the clock input connected to each other the synchronization input of the first trigger 6 and the output of the controlled generator 8 connected by the control input to the output20

The most common of the triggers are b and 7, adders 4 and 5 modulo two, resistors 2 and 3. The resistance of resistor 3 must be two times greater than that of resistor 2.

The duration of negative pulses in signal E at the detector output (Fig. 2n) is proportional to the phase difference At between the input pulse and the generator pulse. When these pulses have a low-pass filter duration of 1 and an inverse Tw / 2. In this case, the voltage on

the output of the filter 1 remains unchanged (equal to 2/3 and where and is the level of the logical "1) and the frequency of the generator 8 does not change. If, the voltage at the output of the filter 1 increases or decreases depending on the bus 12 connected to the input of the second count, 30 sign At, changing the corresponding trigger 13 connected to the output frequency generator 8.

by the output to the input of the first counting trigger 9, which is connected by an output to the synchronizing input of the third trigger 10, connected by information input and output to the output buses 11, and the input

40

through the third counting trigger 14 to the second input of the first adder modulo two, as well as the elements NOT and NAND 15 and 16. In addition, the device contains the third adder 17 modulo two and the fourth trigger 35 of 18, connected by the output to the information the input of the first trigger 6, information input to the output of the third counting trigger 14 and the clock input to interconnected input bus 12 and the input of the element NOT 15 connected by the output to the first input of the element AND-NOT 16 connected by the second input to the output of the second counting trigger 13, moreover, the third adder 17 modulo two is connected to the first input to the inverse output of the first trigger 6, the second input to the output of the second trigger. 7 and exit to the information input of the third trigger 10.

On time diagrams (Figs. 2 and 3), the letter designations of the signals correspond to 50 points of the circuit. FIG. 2 the following notation is used: T is the interval allocated for one bit of information; T-W signal detection window; At - the mismatch between the input pulse and the pulse generator 8; t2 is the trigger switching delay on input C; t4 is the delay of the circuit from the element AND - NOT 16 and

45

A selected binary code sequence is generated at the output of the third adder 17 modulo two (output 1). FIG. 3 shows diagrams for the case when code with a parameter is used. For simplicity, these diagrams are constructed without regard for element delays. The signal controlling the generator 8 is formed from the signal J. As can be seen from the diagram, if Ati + At2 0, the voltage at the input of the generator 8 is 2/3 U. In this case, the frequency of the synchronization series remains constant. If Ati + O, then oscillator 8 changes the frequency of the synchronization series until condition Ati + d1a 0 is met.

Triggers 9 and 10 perform decoding of the selected code sequence when recording information using the modified phase modulation method. The diagrams in FIG. 2

In the proposed device, the detection window is equal to the non-period of the synchronous series.

Claims (2)

Invention Formula A magnetic signal playback decoding device, comprising a low-pass filter, connected trigger 13 on the input R (Fig. 1); ts is the modulo two adder delay 4, 5, and 17. The notation in FIG. 3. TV-detection window; At |, At2 - mismatch between the pulses of the generator 8 and information; U is the logical "1" voltage at the output of the elements. The device works as follows. The trigger 13 and the elements of the NAND and NOT 16 and 15 are the delayed input circuit Q pulses at time t2 (Fig. 26, c). Using triggers 14 and 18, of the delayed and input pulses, respectively, signals of the type BVNM are formed, in which each transition from "O to" 1 and from "1 to" O corresponds to the leading edges of pulses  (Fig. 2d, d). The received signals are fed to the inputs of the phase detector, the state is t5 (Fig. 2d, d). The received signals are fed to the inputs of the phase detector, state 20 The most common of the triggers are b and 7, adders 4 and 5 modulo two, resistors 2 and 3. The resistance of resistor 3 must be two times greater than that of resistor 2. The duration of negative pulses in signal E at the detector output (Fig. 2n) is proportional to the phase difference At between the input pulse and the generator pulse. When these pulses are Tw / d 2. In this case, the voltage on A selected binary code sequence is generated at the output of the third adder 17 modulo two (output 1). FIG. 3 shows diagrams for the case when code with a parameter is used. For simplicity, these diagrams are constructed without regard for element delays. The signal controlling the generator 8 is formed from the signal J. As can be seen from the diagram, if Ati + At2 0, the voltage at the input of the generator 8 is 2/3 U. In this case, the frequency of the synchronization series remains constant. If Ati + O, then oscillator 8 changes the frequency of the synchronization series until condition Ati + d1a 0 is met. Triggers 9 and 10 perform decoding of the selected code sequence when recording information using the modified phase modulation method. The diagrams in FIG. 2 In the proposed device, the detection window is equal to the non-period of the synchronous series. Invention Formula A magnetic signal playback decoding device, comprising a low-pass filter, connected input to interconnected one terminals of the first and second resistors, other terminals connected to the outputs of the first and second modulo-two adders connected by interconnected first inputs to interconnected inverse output of the first trigger and information input of the second trigger connected by the output to the second input the second modulo-two adder and the synchronization input to the synchronization input of the first trigger connected to each other and the output of the controlled oscillator connected the control input to the output of the low-pass filter and the inverse output to the input of the first counting trigger connected by the output to the synchronization input of the third trigger connected by the information input and output to the output rails, and the input strip connected to the input of the second counting trigger connected by the output through the third counting trigger to the second input of the first modulo two adder, as well as NOT and NAND elements, characterized in that, in order to improve the accuracy of information reproduction, the third modulo two and the fourth trigger connected by the output to the information one are entered into it the input of the first trigger, information input - to the output of the third counting trigger and the synchronization input - to the interconnected input bar and the input of the NOT element connected by the output to the first input of the NAND element connected by the second input With the output of the second counting trigger and the output with the installation input of the second counting trigger, the third modulo-two adder is connected by the first input to the inverse output of the first trigger, the second input to the output of the second trigger, and the output to the information input of the third trigger. 5 B) (od , Bbixodi lj m NVshod2 iPU2.2 ti At i R W H Output 1 3 Ji |: 0 Compiled by V. Dobrovolsky Tehred I. VeresKorrektor S. Cherni Circulation 590 Subscription VNIIPI USSR State Committee for Inventions and Discoveries 1 13035, Moscow, Zh-35, Raushsk nab. 4/5 Production and printing company, Uzhgorod, ul. Project, 4 L fpa2.3