SU734803A1 - Device for line-wise recording onto and reproducing from magnetic tape - Google Patents

Description

one

The invention relates to the field of instrumentation, in particular to the technique of magnetic recording, and can be used to record broadband analog signals.

A device for in-line magnetic recording is known, comprising a block of rotating magnetic heads associated with recording and reproducing channels 1.

One of the drawbacks of this device is the presence of temporal distortions of the reproduced signal due to changes in the geometrical dimensions of the magnetic tape and the rotating disk with magnetic heads installed on it ("jagged distortions").

The closest in technical essence of the present invention is a device for line recording and reproduction on a magnetic tape, comprising a rotating magnetic heads unit connected through the first recording channel to the input terminal, and through the first playback channel to the output terminal, as well as to the second channels recording and playback 2.

A disadvantage of this device is the impossibility of eliminating jagged distortions during recording and reproduction of any non-television signals, since these signals do not have horizontal sync pulses, and therefore it becomes impossible to control the vacuum guide block of rotating heads, which leads to significant time distortions .

10 The aim of the invention is to reduce the temporal distortion of the reproduced signal when recording and reproducing analog broadband signals.

The goal is achieved by the fact that a device containing a block of rotating magnetic

5 heads connected through the first recording channel to the input terminal, and through the first playback channel to the output terminal, as well as to the second recording and playback channels, two channel channels are introduced

25 electronic recording and playback switches, a reference pulse generator and a time interval meter, with the outputs of the electronic recording switch switch connected to the inputs of the recording channels.

and the inputs to the input terminal and to the output of the reference pulse generator, the inputs of the electronic playback switch are connected to the outputs of the playback channels, and the outputs to the output terminal and through a time interval meter with a control input of a rotating magnetic heads unit, the third output of which is connected to inputs of both electronic switches.

FIG. 1 shows a section of a magnetic tape with conventionally shown lower case recording, and FIG. 2 is a block diagram of the proposed device.

A lower case multi-head magnetic recording (FIG. 1) consists of alternating even 1 and odd x 2 recording lines. The length L of each recording line is selected slightly longer than the length I equal to the distance between the working gaps of the magnetic recording heads, measured around the circumference of the rotating disk, due to which the same signal is recorded in sections di and d g of adjacent lines, i.e. . a temporary overlap of lines occurs.

This device allows to record special reference pulses in the overlap zone at the beginning and at the end of each line. If, during the reproduction of such a waveform, the distance between the working gaps of the heads, measured around the circumference of the rotating disk, differs (for example, by changing the temperature) from the distance that was recorded, the time difference (at the same speed of rotation of the disk) between the reproduced reference the pulses will not match the time difference between it when recording. Since during the recording the reference pulses are generated at strictly defined points in time, then, by measuring the time between the reference pulses with reproduction with the required accuracy, information is obtained about the magnitude of the temporal (jagged) distortions. The information obtained in this way is used to control the corresponding compensators of temporal distortions (in the simplest case for controlling the vacuum guide block of the rotating heads.

The device for line magnetic recording-reproducing (Fig. 2) consists of channels 3 for recording even and channels 4 for recording odd lines, a block of rotating heads 5 from the vacuum guide and channels 6 for reproducing even lines and channels 7 for playing odd lines. The device additionally includes a generator of reference pulses 8, an electronic recording switch 9, an electronic playback switch 10, and a meter 11 between the reproduced reference pulses. The outputs of the electronic recording switch 9 are connected to the inputs of the recording channels 3 and 4, and the inputs to the inputs

12 devices of magnetic recording and the output of the generator of reference pulses 8. The inputs of the electronic playback switch 10 are connected to the outputs of the playback channels 6 and 7, and the outputs to the output 13 of the device and to the input of the time interval meter 1, the output of which is connected to the control input of the rotating unit heads 5, and the rotating heads unit 5, in turn, is connected to the control inputs of both electronic

switches 9 and 10.

During playback, both channels of the electronic playback switch 10 are switched synchronously at the instants of time determined by the clock generator tachrgenerator 5. When recording goes from odd lines 2 to even 1 channel "a" electronic recording switch 9, switches and channel "b" switches to a later point of time. As a result of the non-synchronous triggering of the channels

0 and b of the electronic recording switch 9 partially overlap the recording time of the main signal from the input of the device 12, which is necessary for correct (lossless) reproduction of the recorded signals.

The reproduced signals, separated by an electronic playback switch 10 into two channels, arrive: the main signal is at the device output 13, the reference pulses are sent to the time interval meter 11 between them, which produces a signal proportional to the time error. This signal controls the electromechanical drive of the vacuum guide block of the rotating heads 5.

Claims (2)

1. Goncharov, AV and others. Technique of magnetic video. M., Energie 1970, p. 47 2. VCR Frame-3, Novosibirsk (prototype).