SU1566405A1 - Device for multichannel magnetic record and reproduction of signals - Google Patents

Abstract

The invention relates to a magnetic recording technique, namely, devices for correcting temporal distortion of magnetic recording signals. The purpose of the invention is to improve the accuracy of the correction of temporal distortion when recording reference and information signals on different tracks. All channels are divided into groups, each of which is formed from two reference signal recording channels and one information signal recording channel, with the information signal recording track located between the reference signal recording tracks. In each subsequent, after the first group of channels, the second channel of the reference signal of the previous group of channels is used as the first channel of the reference signal. The reference signals are recorded simultaneously on all tracks of the reference signals from a stable frequency generator. During playback, the information signals in each channel are amplified, delayed by the time equal to the generation time of the control signal by the analog-digital converter and the buffer accumulator, converted into digital code in the analog-digital converter and stored in the buffer accumulator at a frequency proportional to the frequency of the reference signal reproduced from the carrier records The reading from the buffer accumulator is performed at a stable frequency. After digital-to-analog conversion and filtering, an analog signal is generated at the output of the device with reduced temporal distortion.

Description

The invention relates to a technique of magnetic recording, in particular, to devices for correcting temporal distortions arising in the process of recording and reproducing, and can be used in devices for precise magnetic recording of analog signals.

The purpose of the invention is to increase the faithfulness of reproduction.

The drawing shows a block diagram of the device.

The device contains in the recording channel input bus 1 information signals connected via amplifier 2 recordings to

heads 3 record information signals on the recording medium 4, heads 5 record the reference signal connected to the output of the reference signal generator 6, and in the playback channel, the information heads 7 and 8 reference signals connected to the inputs of the information amplifiers 9 and reference 10 signals,

At the same time, in each group of channels formed from two channels for recording the reference signal and one channel for recording the information signal, the recording track is information

The signal is located between the reference signal recording tracks, and in each subsequent group of channels, the second channel of the previous channel group is used as the first signal drop, with the output of amplifier 9 in each channel group connected to the output bus 11 via serially connected lines 12 delays, the first low-pass filter 13, the analog-to-digital converter 14, the buffer storage 15, the digital-to-analog converter 16, and the second low-pass filter 17. The second input of the accumulator 15 is connected to the output of the stable frequency generator 18 common to all channel groups, and the third input of the accumulator 15 is connected to the second input of the converter 14 and connected to the output of the amplifier 10 of the first channel of the reference signal through a series-connected pulse former 19 a filter 20, a controlled oscillator 21, an adder 22, a third low-pass filter 23 and a first phase detector 24. The second input of the latter is connected to the output of the amplifier 10 of the second channel of the reference signal through the phase shifter 25, and the second The output of the adder 22 is connected to the output of the amplifier 10 via a fourth low-pass filter 26 and a second phase detector 27, the second input of which is connected via a frequency divider 28 to the output of a controlled oscillator 21.

The device works as follows.

Signals are simultaneously recorded on carrier 4 through amplifier 2 and the reference signal from oscillator 6. It is advisable to use harmonic as a reference signal. During reproduction, line 12 equalizes the passage of signals to the inputs of converter 14. After reading the code words from the buffer accumulator 15, an information signal with a smaller time distortion is generated at a stable frequency. The reference signal from the heads 8 enters the phase detectors of each channel. The signal for controlling the transducer 14 is extracted using a phase detector 27 included in a phase locked loop (PLL) circuit that multiplies the frequency. input signal to the desired value. Since the reference signal is recorded on a track adjacent to the information signal, it contains information not only about temporal distortions caused by speed fluctuations, but also temporal distortions caused by distortions of the carrier relative to the heads.

To reduce the effect of skewing on the accuracy of forming the control signal of the converter 14 and the accumulator 15, a signal is input to the second input of the adder 22,

proportional to the interchannel time distortion between the first and second channels of the reference signal in antiphase to the signal generated at the output of the phase detector 24 This leads to a decrease in

0 in the output signal of the generator 21 components caused by inter-channel skews. The signal of inter-channel skews is formed by comparing in phase in the detector 24 reference signals of the first and

5 is shifted in phase by 90 relative to it using the phase shifter 25 of the second channel of the reference signal a. The signal between channel skews from the filter 23 output goes to the second input of the adder 22. For

0 eliminating the influence on the accuracy of the formation of the control signal of the converter 14 and the buffer storage 15 components multiplied by the control frequency divided by the divider coefficient 28,

5, a band-pass filter 20 is introduced with a passband corresponding to the width of the temporal distortion spectrum to be corrected. Shaper 19 converts the output signal of the filter 20 to pulses,

0 required to control the converter 14 and the drive 15

The recording of the reference signal in two tracks, on either side of the information signal track, allows

Claims (1)

5 to generate an analog-to-digital converter control signal containing components proportional to the intra-channel temporal distortions of the information signal channel, and, consecutively, to improve the accuracy of correcting the time distortions in each channel. Invention formula for multi-magnetic recording and reproducing signal 5 . containing in the recording channel the input buses of information signals, each of which is connected to the recording head of the information signal, the reference signal generator, the reference signal recording head, and in each group of playback channels - the information and reference signal playback heads connected to the corresponding amplifiers playback, delay time, 5 analog-to-digital converters, buffer drives, digital-to-analog converters, and a stable frequency generator, characterized in that, in order to improve fidelity of reproduction, they are introduced into each group of channels the first low-pass filter connected between the delay line and the analog-to-digital converter input, the second low-pass filter connected between the output of the digital-to-analog converter and the output bus, the phase shifter connected in series, the first phase detector and the third low pass filter connected in series to the second phase detector, fourth low-pass filter, adder, controlled oscillator, band-pass filter, pulse shaper, the output of which is connected to the second input of the analog-digital converter azovatel and the second input buffer accumulator, a frequency divider connected between the output controllably genera0 the second input of the second phase detector, the output of the stable frequency generator is connected to the third input of the buffer accumulator, the output of the third low-pass filter to the second input of the adder, the output of the first playback amplifier of the reference signal-with the inputs of the phase shifter and the second phase detector, the output the second playback amplifier of the reference signal — with the second input of the first phase detector; the output of the playback amplifier of the information signal — with the input of the delay line; the output of the reference signal generator ala recording channel - with a reference signal write heads,