SU903964A1 - Device for reproducing two-frequency digital information - Google Patents

Description

(5) DEVICE FOR REPRODUCTION OF TWO-FREQUENCY DIGITAL INFORMATION

one

The invention relates to instrumentation, namely, devices for recording and reproducing information, and can be applied to equipment with a digital dual-frequency recording method.

A device for reproducing digital dual-frequency signals, the principle of operation, is based on analyzing the presence or absence of information pulses at certain time intervals after the detection of clock sync transitions. Timer 13 is used as a circuit that sets this time interval.

The drawback of the device is low noise immunity caused by the absence of blocking elements at its information input, as well as limited functionality associated with the absence of a block for fixing clock transitions, expressed in the impossibility of reproducing marker bytes.

The closest to that proposed by the technical nature is; A device for reproducing two-frequency digital information containing a reproducing unit, a shift register, element 2I and a marker byte decorator, as well as four flip-flops, two two-bit registers, a master oscillator, additional four elements 2I, two elements ZI, element, four elements 2LI, and additional 8-bit shift register Pi Analysis of the incoming code combination carried out by the data; the device is produced in shift registers interpreted by the master oscillator, and the circuit can be started with both clock and information pulses C2.

Claims (2)

The device has high noise immunity and allows to reproduce marker bytes, however, it is large. The second amount of equipment contained in it leads to poor reliability. The purpose of the invention is to increase the reliability of the device and its simplification. The goal is achieved by the fact that a device containing a playback unit, a shift register, element 2I, and a marker byte detector equipped with two one-oscillators and a delay element, the input of the first one-oscillator connected to the output of the reproducing unit, the inverse output of the first one-oscillator connected to the first input of the element 2I and to the input of the delay element, the output of which is connected to the input of the second one-shot and to the information input of the shift register, while the gate input of the latter is connected to the output m 2I element Auto swarm input connected to inverted. the output of the second one-shot, and the outputs of the shift register are connected to the inputs of the marker byte detector. FIG. 1 is a block diagram; on fmg. 2 - time diagrams. The proposed device consists of a shift register 1, the outputs of which are connected to the inputs of the detector 2 marker bytes, and the gate input is connected to the output of element 2 and 3 whose first input is connected to the inverse output of the first oscillator and the input of delay element 5, the output of which is connected to the information input the shift register 1 and with the input of the second one-shot 6, while the inverse output of the second one-shot 6 is connected to the second input of element 2I 3 and the input of the first one-shot A is connected to the output of the unit izmeni (not shown). The device works as follows. The information intended for decoding is fed to the input of the first one crater. In this case, the sequence of impulses with the period corresponds to the information O, and the period T / g i / 8 of information 1 (Fig. 2, A). On the leading edge of the incoming pulse, the first single vibrator k is triggered, while the duration of its output pulse is 7/20 T (Fig. 2, B). During this period, the device does not perceive the input information, thereby eliminating the possibility of false triggering from the disturbance. At the gate input of the shift register 1, this sets a low potential, since element 2 and 3 is closed. After 7/20 T after launch, the first single vibrator k returns to the initial state. When this opens element 2 and 3 (Fig. 2, E), a positive voltage drop is formed at the gate input of the shift register 1 by writing to it the delayed state of the first single vibrator i (Fig. 2, C). At the information input of the shift register 1, the potential is low. The delay is determined by the $ delay element and is T / Do. Therefore, the second one-shot 6 starts after 3/8 T after starting the first one-shot k, overlapping element 2I 3 at the second input. If the distance between adjacent data pulses is T / 2tT / 8- (Fig. 2A), The first single vibrator 4, running on the leading edge of the next pulse, overlaps element 2I 3 on the nefiaoMy input ..- Since the duration of the output pulse of the second single-axis 6 also amounts to 7/20 T, TOj therefore. the rear front is ahead of the rear front of the output pulse of the first single-oscillator k, and therefore, at the time of a positive voltage drop at the inverse output of the second single-oscillator 6, element 2 and 3 is still blocked by the first input. Writing information into the shift register 1 will occur in this case along the falling edge of the output pulse of the first one-oscillator C. If the distance between the data pulse is T ± T / 4, then at the moment of a positive voltage drop on the inverse output of the second one-oscillator 6, the element 2 and 3, opens, at its first entrance at this time a high potential. In this case, at the time of recording, a high potential is established at the information input of the shift register 1. With the arrival of the next data pulse, the device will again work according to the algorithm described above. Thus, when playing data with a frequency of 1 / T in shift register 1, a combination of 10 10 101 ... is written, and at a data frequency of 2 / T - 00000000. For example, each byte is assigned a 16-bit code combination Detection code combinations corresponding to marker bytes are implemented in detector 2 of marker bytes. The information bytes can be read in parallel code directly from the output buses of the shift register 1, with the information transition corresponding to even bits, counting from the most significant one. The number of equipment of the proposed device was reduced by more than two times as compared with the known device. DETAILED DESCRIPTION OF THE INVENTION A device for reproducing two-frequency digital information, comprising a playback unit, a shift register, element 2I, and a marker byte detector, distinguished from that, c. In order to improve the reliability of the device and simplify it, it is equipped with two single vibrators and a delay element, we accept the input of the first single vibrator v connected to the output of the playback unit, the inverse output of the first single vibrator is connected to the first input of the element 2I and to the input of the delay element whose output is connected to the input of the second one-shot and with the input of the shift register, while the gate input of the latter is connected with the output of the element 2I, the second input of which is connected to the inverse output of the second one ibratora, and the outputs of the shift register are connected to inputs of the marker detector bytes. Sources of information taken into account in the examination 1. Zavvka FRG G 11 “9A27, cl. & 11/5/02, published 1976. 2.Patent of Great Britain N 1536530 cl. & 4 With, pub. 12.20.78. (prototype). I VI L V Vi AT. "four; 3 P l Phia.2.