SU696528A1 - Device for self-synchronizing in reproduction apparatus - Google Patents

Description

The invention relates to the field of instrumentation and can be used as a self-synchronization device in a digital magnetic recording device. A self-synchronization device is known that has a sufficiently high stability due to the use of a narrowband filter 1. But this advantage becomes a disadvantage when it becomes necessary to reproduce local frequency oscillations arising for various reasons. The reason is the narrowband filter. It is also known a self-synchronization device in an apparatus for playing a digital magnetic recording, consisting of a phase detector, as well as a series-connected differential amplifier, integrator, sug-1mator, controlled oscillator and counter 21. However, this device does not have a sufficiently high reproducibility information from a magnetic carrier at current oscillations of the frequency of reproduced signals. The aim of the invention is to improve the accuracy of reproduction of information from a magnetic carrier with local fluctuations of the frequency of the reproduced signals. This goal is achieved due to the fact that the device is equipped with two symmetric channels connected between different outputs of the phase detector and different inputs of the differential amplifier, each of which contains a delay unit, as well as the first and second inverters connected via a trigger and an OR circuit. And, at the same time, the output of the circuit AND is connected to a separate input of the differential amplifier, the output of the phase detector to the inputs of the first inverter and the delay unit, to the second input of cxeNbi I and to the separate input of the trigger of another channel, and the output of the counter to a separate input phase detector. the drawing shows a block diagram of the described device. Phase detector 1 through shaper 2, filter 3 and adder 4 is connected to controlled generator 5, shaper 2 and blocks 6 and 7, inverters 8-11, trigger 12 and 13, OR circuit 14 and 15, and AND circuit 16 and 17. A filter 3 includes a differential amplifier 18 and an integrator 19, and a controlled oscillator 5 - a controlled x-oscillator 20 and a counter 21.

The phase detector has inputs 22 and 23, output 24; inverter 8 - output 25; delay unit (OT) 6 - output 26; inverter 10 - output 27; trigger 12 output 28; scheme OR 14 - output 29; scheme 16 and output 30; phase detector (PD) - output 31; inverter 9 output 32; БЗ 7 - exit 33; inverter; 11 - output 34; trigger 13 - exit 35; scheme OR 15 - output 36; scheme And 17 - exit 37; Differential amplifier (RC) 18 — output 38 and adder 4 — output 39. Shaper 2 consists of two symmetrical channels 40 and 41, each of which operates equally with the other channel.

When the device is in synchronization mode, the shift of the working Impulse can cause an error pulse at the output 31, and since the duration of this pulse is longer than the delay time at the KB 7, the signal at output 32 (but if there is a sufficiently high signal level at output 33) includes - trigger 13, and this leads to the shutdown of channel 40. As a result, the error pulse is shortened to a duration commensurate with the delay time of the BR 7. The above happens with the participation of the signals available at outputs 31 and 36. Further The formation of individual pulses or their groups is possible with the participation of all elements of each channel. So, for example, the signal at the output 36 of the OR circuit 15 is formed from the signals coming from the outputs 34 and 35, and the signal at the output 35 in turn is formed by the trigger 13, which is activated by the falling edge of the error pulse (or other pulse) present in the signal at output 32. This is possible provided that at the other input of the trigger, i.e. There is a high signal level at the input connected to output 33. Channel 40 also works in the same way. "

As a result, it should be noted that the appearance at the output, for example 24, of two or more error pulses

another indicates a sharp local shift of the clock cha; lorn of the reproduction signal on the input 22. In this case, the second pulse, as well as the subsequent pulses, is not narrowed, but is transmitted with the initial duration, which allows the device to operate with a high degree of reliability.

Device capability effectively

suppress interference when necessary, and the complete automaticity of such a suppression process makes the device as a whole economical and increases the reliability

 reproducible information.

Claims (1)

Invention Formula A self-synchronization device in a digital magnetic recorder playback apparatus, consisting of a phase detector, as well as a series-connected differential amplifier, integrator, adder, controlled oscillator and counter, in order to improve the accuracy of reproducing information from magnetic carrier with local oscillations of the frequency of the reproduced signals, it is equipped with two different simulators connected between different outputs of the phase detector and different inputs: a differential amplifier Each channel contains a delay unit, as well as the first and second inverters connected via the trigger and the OR circuit to the AND circuit, the output of the AND circuit is connected to a separate input of the differential amplifier, the output of the phase detector with the inputs of the first inverter and unit delays, with the second input of the And circuit and with a separate trigger input of another channel, and the output counter - with a separate input phase detector. Sources of information taken into account in the examination 1. US Patent 3,810,234, cl. 340-174.1, 1974.2. U.S. Patent 3,831,195, Cl. 360-51, 1974 (prototype). J th j1 2 , -ft f W five / 12 , one 79 Yy Y5 and 3S