SU1282196A1 - Device for recording and reproducing frequency-modulated signals - Google Patents

Abstract

The invention relates to magnetic recording and makes it possible to improve the accuracy of the correction of temporal distortions. Each codeword is written to the drive 12 synchronously with a code generator at the output of the analog-digital converter 11, and the reading is performed at a stable frequency generated by the reference frequency generator 15. The output of the device after converting code words read from accumulator 12 in a digital-to-analog converter to analog form and filtering it in filter 17 generates an information signal with a smaller temporal distortion than at the input of the device, because after frequency detector 8 the upper frequency spectrum of the information signal is lower upper frequency spectrum of frequency-modulated signals. This allows the analog-to-digital converter 16 to be implemented at a lower frequency than the intended purpose of the invention. 1 il. W

Description

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The invention relates to magnetic recording, in particular, to devices for correcting temporal distortions that occur during recording and reproduction, and can be used in devices by a magnetic recording point of analog signals.

The purpose of the invention is to improve the accuracy of the correction of temporal distortion.

The drawing shows a block diagram of the device.

A device for recording and reproducing frequency-modulated signals in a recording channel contains a reference frequency generator 1, a voltage suppressor 2, a frequency modulator 3, a recording amplifier 4 and a recording head 5, and in the playback channel - a reproducing head 6, amplifier 7, a frequency limiter detector 8 first low-pass filter 9, delay line 10, analog-to-digital converter 11, accumulator 12, frequency multiplier 13 and band-pass filter 14, reference frequency generator 15, digital-to-analog converter 16 and second lower filter 17 x frequencies.

The device works as follows.

In the recording mode, the information signal is fed to the input of the adder 2, where it is added to the signal of the reference frequency generator 1 lying outside the spectrum of the information signal. The sum of the reference and information signals is subjected to frequency modulation in frequency modulator 3, amplified in record amplifier 4, which forms the current required for recording, and fed to head 5, which records the frequency modulated signal on magnetic recording medium (not shown). The reproduced head 6 frequency-modulated signal is amplified and limited at the zero level in the limiting amplifier 7 and detected in the frequency detector 8. As a result, the output of the detector 8 generates a signal proportional to the sum of the information and reference signals subject to temporal distortion. the signals are filtered out by filters 9 and 14, respectively, and an information signal through a delay line 10, equalizing the time it passes through the circuit of filter 9 with the time it takes to pass polar signal

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through the circuit: filter 14 and frequency multiplier 13, is fed to the input of analog-digital converter 11, which is converted into a digital code

with frequency E, DR, a multiple of the frequency of the reference signal. The reduction ratio n of the reference frequency f is selected from the condition n i 3fg / fon, where fg is the upper frequency in the spectrum of the information signal. Each codeword is written to accumulator 12 synchronously with the generation of a code at the output of analog-digital converter 1 I with a frequency subject to the same temporal distortion as the information signal, and reading from accumulator 12 is performed with a stable frequency generated by the reference frequency generator 15 and equal to the average value of f

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thanks to what the output

devices after converting code layers read out of accumulator 12 in digital-to-analog converter 16 to analog form and filtering it in filter 17, an information signal is generated with much less time distortion than at the input of the device, because after frequency detector B the upper frequency spectrum of the information signal turns out to be 4-5 times lower than the upper frequency of the spectrum of frequency-modulated signals, this allows you to perform analog-digital conversion at a lower frequency than is achieved The effect of expanding the limits of compensable time distortion while maintaining the same storage capacity and high accuracy of the correction of time distortion.

Claims (1)

Invention Formula A device for recording and reproducing frequency modulated signals, comprising a reference frequency generator in the recording channel, an output connected to one input of the adder, a frequency modulator and a recording head with a recording amplifier, and in the playback channel - a playback head, a frequency detector, the first low pass filter filter, analog-to-digital converter, output connected to the first input of the accumulator, generator of the reference frequency, connected to the second input of the accumulator, the output of which is connected to the input of the digital-to-analog converter, is that with the purpose of improving the accuracy of the correction of temporal distortions, an amplifier-limiter, a delay line, a frequency multiplier and a second low-pass filter, in the recording channel another input of the adder is connected to the information input of the device, another input of the adder is connected to the input of the recording amplifier, in the playback channel the playback head, i.e. The primary detector, the frequency detector, the first low-pass filter and the delay line are connected to the first input of the analog-digital converter, the output of the partial detector is connected via a serially connected band-pass filter and the frequency multiplier is connected to the second input of the analog-digital converter and to the third input of the drive.