SU622148A1 - Arrangement for discriminating information from frequency-modulated signals - Google Patents

Description

one

The invention relates to the field of instrumentation and is intended for use in magnetic drum, disk and tape storage devices.

A device for extracting information used in the field of automation and computer technology 1.

In this device, the separation of synchronizing pulses and information occurs with the help of two elements And two inputs and two one-shot. The selected synchronizing pulses trigger the first one-shot, forming pulses with a duration of 0.25 T (T is the duration of one digital position) and used as a delay line. The second one-shot starts at the falling edge of the pulses from the first one-shot and generates pulses with a duration of 0.5 T. The zero output of the second one-shot goes to the AND element, which selects synchronizing pulses, and the single output - to the AND element, which separates information pulses. A frequency-modulated signal is applied to the second inputs of these elements.

The disadvantage of this device is a relatively small tolerance on the phase distortion of the frequency-modulated signal, which theoretically is equal to ± 0.125 T.

The closest in technical essence to the invention is an information extraction device that is used in a 1BM-2314 magnetic disk drive.

This device extracts information from a frequency-modulated signal, containing a phase discriminator connected to the device input, a generator, an input connected to a phase discriminator, and the output simultaneously connected to a delay line and a second input

phase discriminator, single-digit counter, output connected to the logic circuits And, the second inputs of which are interconnected and connected to the input of the device 2.

The circuit implementation of such a device is quite complicated, in particular, the detector of zeros is made on special elements (linear voltage generators, comparators, etc.) sensitive to temperature fluctuations, the implementation of which uses precision components. In the production process, these elements require adjustment.

The aim of the invention is to increase the reliability of reproduction.

The goal is achieved by introducing an inverter into the device, connected to the device input, and connected to a single-digit counter, the second counter connected to the device input, three shift circuits, and a ZI-2IL logic circuit, the output of which is connected to the initial input installation of the first counter, two inputs of the ZI-2ILI logic circuit are connected to the outputs of the second counter and to one of the inputs of the first shift circuit, the second input of which is connected simultaneously with the second pair of inputs of the ZI-2ILI circuit, with the input of the second shift circuit and the output of the delay line, while the outputs of the first and second shift circuits are connected to the input of the third shift circuit, the outputs connected to the ZI-2IL circuit.

FIG. 1 shows a block diagram of the device; FIG. 2 - time diagrams of his work.

The device consists of a generator 1, a phase discriminator 2, a delay line 3, a logic for extracting information from a bullet, including a one-bit counter 4, a shift circuit 5-7 and a 2P1LI 8 ZI circuit and a logic circuit for separating information and synchronizing pulses, including an inverter 9, one-bit counter 10 and elements 11, 12.

The frequency-modulated signal is fed to phase discriminator 2, which controls the frequency and phase of oscillations of generator 1. Generator 1 is synchronized as follows. The pulses of the frequency-modulated signal are compared in phase with the output signal of the oscillator 1. In the presence of a phase mismatch, an error voltage is generated that changes the frequency of the oscillator 1 in the direction of reducing the error. The phase discriminator and the generator form a closed-loop system of frequency and phase, with inertia. The frequency-modulated signal is also fed to a one-bit counter 4 of the information zero-allocation circuit. The census of information from counter 4 to the first trigger of the shift circuit 5 occurs from the generator 1, delayed by delay line 3 by 0.25 T. The coding of information from the first trigger of the shift circuit 5 to the second trigger of circuit 6 occurs via the synchronization circuit of the shift circuit 7. The single and zero outputs of the one-bit counter 4 and the second trigger of circuit 6 are fed to the ZI-2ILI 8 circuit, in which gating of the synopsepHE signals from Line 3 takes place. Distributed; the zero information from the ZI-2ILI 8 scheme makes the initial installation of a one-bit counter 10, to the input of which pulses are fed from the inverter 9. The input of the inverter 9 receives pulses of a frequency-modulated signal. b; the single output of the counter 10 is connected to the AND element, and the zero output is connected to the AND 12 element. Information 11 pulses are output by AND 11 element, and the frequency-modulated signal clock pulses are output by AND 12 element.

In the device, the selection of zero-point pulses is implemented using standard logic elements, due to which the device is simplified and the reliability of operation is improved.

Claims (2)

1. US Patent No. 3217329, cl. 346-74, 1965. 2. Technical description of the OVC on removable magnetic disks CMM 2314 and additional control device IBM 2844. Translation No. 1681, 1973, UDC, 681.327.63:: 681.32ЬЗ. R . A and J 1 W P P P J and G IT 1G .-R. l jO., ..