SU633064A1 - Apparatus for reproducing phase-modulated signal from magnetic record carrier - Google Patents

Description

The invention relates to the field of instrumentation and is intended for use in storage devices of computers on magnetic tapes, disks and a drum. In modern storage devices, the method of relative phase magnetic recording and the detection of signals at a suppressive signal with a read signal of the corresponding positive and negative levels is used. The known devices do not allow to obtain a high noise immunity of detecting the detected signal as a result of the fact that the detection is performed over a small portion of the reproduced signal ij. Of the known devices for reproducing a phase-modulated signal from the carrier, the closest in technical essence is a device containing a null organ, the output of which is connected via a delay line to the valves and a trigger, a mismatch circuit connected to the input to the valve, and the output to the multivibrator, as well as a pulse shaper connected to the trigger input 2. A disadvantage of the known device is the inadequate noise immunity of the signal detection unit as a result of the fact that signal detection is performed on a small portion of the reproduced signal (in small neighborhoods of a certain positive and negative threshold value, which, when two impulse noise of opposite polarities occurs, leads to a detection error signal). In addition, it contains a large number of electronic components. The aim of the invention is to improve the noise immunity and simplify the device. This is achieved by the fact that the proposed device is additionally equipped with an integrator and a delay line, the integrator input is connected to the input bus of the device, and the integrator output is connected to the input of the tripper through a valve, and the output of the zero-organ is connected to another input of the valve. FIG. 1 is a block diagram of the described device; on I1. 2 - timing charts of the device.

US ..: -o ;, SOBO CONSISTING of null organ 1, flip-flops 2, 3 l 4, gates 5, 6, 7 and 8, multivibrator 9, cxeMt mismatch 10, delay pins 11 and 12, integrator 13, pulse former 14. The input signal is fed to the threshold 15, and the output of the device is the buses of code ig-pulses 16 and synchronization and / pulses 17. The device is put in the initial state by a pulse arriving on the bus 18.

The device works as follows.

Triggered from the zero signal level (plot I, fig. 2), the null organ 1 produces pulses (plot 2, fig 2), which through the delay line 12 arrive at the input of the valve b. The read signal is also fed to the input of the integrator 13, which integrates the read signal. At the integrator output, a certain voltage value obtained corresponding to the integrated value of the first half period of the carrier frequency (plot 3 of Fig. 2} f opens valve 5, and the pulse from the output of the null organ 1 sets trigger 2 into one state. High potential at a single output, de flip-flop 2 (plot 4, figure 2) opens valve b, and the delayed delay line 12 impulses from the output of the null organ 1 pass through valve b and arrive at the input of the mismatch circuit 10 (plot 5, fig. 2) and -line Delay 11 - to the counting input of trigger 3 (plot b, phi d, 2). This 1 mp pulse passes through the mismatch scheme 10 and starts the multivibrator 9, the output pulse duration of which is chosen at a different 3/4 period of the E-frequency frequency (plot 7, fig. 2). Trigger 3 (plot 8, fig 2) controls the valves 7 and 8, to the other inputs of which synchronizing pulses are received from the output of the mismatched circuit:: C: (in the diagrams 9 and 10 of Fig. 2

shows the output pulses of these gates). In the case of reading the signal of the unit, the trigger 4 changes its state (plot 11, fig. 2) and a code pulse (plot 12, fig. 2) formed by the pulse shaper 14 on the output bus 16. Synchronizing pulses arrive on the bus 17 . Upon completion of reading the information, the impulse arriving at the bar 18 sets the device to its initial state.

The noise immunity of the proposed device is higher, since it is insensitive to short-term positive and negative emissions,

that take place during magnetic recording-playback.

Claims (2)

1. USSR Author's Certificate No. 336681, cd. q 11 B 5/02, 1970. 2. USSR author's certificate l-i 349017, class, Q 11 V 15/00, 1970.