SU1513510A1 - Videotape recorder - Google Patents

Abstract

The invention relates to the field of magnetic recording and can be used in devices that perform line-by-line recording of information. The invention makes it possible to increase the reliability of a video recorder. The video recorder works as follows. In the recording mode, an information signal is supplied to the movable head through the modulator. In accordance with this signal, the generatrix of the recording is modulated. In the playback mode, as a result of a change in the phase of the reference pulses, the recorded additional information is read out, moreover, in order to reproduce the additional information signals and there is no need to use a mobile playback head with a complex control unit. 2 Il.

Description

The invention relates to magnetic recording and can be used in devices that perform line-by-line recording of information, in particular in video recorders.

The purpose of the invention is to increase the reliability of a VCR by simplifying it.

Figure 1 shows the structural scheme of a VCR; Fig. 2 shows voltage plots explaining the operation of the proposed VCR.

. The VCR contains serially connected elements of the recording channel: information signal pin 1, modulator 2, drive 3 recording heads and recording head 4. The kanagg playback consists of a playback head 5 connected through an envelope detector 6 to a demodule -

The torus 7. At the same time, the reproduction head is connected to the serially connected absolute magnitude separation unit 8, the first comparator 9, the low-pass filter 10, the second comparator 11 and the inverter 12. The inverter input is connected to the control input of the key 13, and the output is with the control input of the key 14, which is connected between the reference signal bus 15 and the first input of the summing device 16, the output of which is connected to the automatic tape speed control system (SARSL) 17. The reference signal bus 15 is connected Through the device 18 of the delay, and the key 13 to the second input of the summing device 16.. The video recorder works as follows.

SP

with

SP

1513510

When writing, the stitches are modulated in accordance with the additional information signal received via bus 1 (Fig. 2a), as the recording head 4 rotates while moving in a direction parallel to the axis of rotation. The latter is due to the drive 3 being driven by the output of the modulator -2.

During playback, the key 1A closes (the key 13 is open at this moment) and pulses from the reference signal bus 15 start to arrive at HARCF 17. As long as the speed of tape sweeping in a VCR (controlled by SARSL) does not reach the nominal (i.e. that which was at the time of recording), the frequency-modulated oscillations U at the output of block 8 (Fig. 26) can have an amplitude the higher or lower voltage U ,, which is the reference for comparator 9. The absolute magnitude selection unit 8 converts the bipolar signal of the reproduction head 5 and the ' (FIG. 2a) into a unipolar U (FIG. 26, individual amplitude modulated oscillations are not shown, but only their envelope is shown ; Phantom boundary denoted additional information signal recording area). At the output of the comparator 9, pulses appear (Fig. 2b, the signals filling them are not shown), which, after being fed into the low-pass filter 10, are converted into a constant voltage and, lower in amplitude reference

ten

15

It goes and the key 13 opens, as a result of which the phase of the reference changes due to the action of the delay device 18. arriving at SARSL. The head 5 is shifted to position II (fig. 2a) and, in addition to the image signal, reproduces the additional information signals detected by blocks 6 and 7.

Consequently, in order to reproduce the signals of additional information in the proposed VCR, there is no need to use a movable playback head with a complex control unit.

Claims (1)

Invention Formula A video recorder containing an information signal serially connected, a modulator, a recording head, a recording head, and a playback head,. connected through a frequency-modulated signal envelope detector to a demodulator, a reference signal bar connected to a delay device, an automatic tape speed control system, first and second comparators, first and second electronic keys, outputs connected to a summation device, that, in order to increase the reliability of the operation by simplifying the device, a block for the absolute value of the signal is inserted into it, the input is connected20 25 35 voltage U of comparator 11 (figv), JQ to the playback head, filter In this case, the output of the comparator 11 is high potential, the output of the inverter 13 is low potential, the key 13 is closed, and the key 14 is open. After the tape speed in the video recorder becomes nominal, i.e. it moves synchronously and in phase with the reference signal acting on the bus 15, the playback head 5 is in position I (Fig. 2a). Moreover, the envelope and is already located above U (Fig. 2b), the duration of the pulses 11 c (Fig. 2c) increases, their constant 50 a low frequency and an inverter, the absolute value selection block is connected to the inverter through a first comparator connected in series, a low pass filter, a second comparator, the first input of the first electronic key connected to the output of the delay unit, its second control input connected to the output of the second comparator , the first input of the second electronic key is connected to the reference signal bus, its second control input is connected to the output of the inverter, and the output of the summation device is connected to the input of the auto system aticheskogo control skorosti.lenty. on the component U p, increases and exceeds the reference level and the comparator 11. In this case, the key 14 is closed four It goes and the key 13 opens, as a result of which the phase of the reference changes due to the action of the delay device 18. arriving at SARSL. The head 5 is shifted to position II (fig. 2a) and, in addition to the image signal, reproduces the additional information signals detected by blocks 6 and 7. Consequently, in order to reproduce the signals of additional information in the proposed VCR, there is no need to use a movable playback head with a complex control unit. Invention Formula A video recorder containing an information signal serially connected, a modulator, a recording head, a recording head, and a playback head,. connected through a frequency-modulated signal envelope detector to a demodulator, a reference signal bar connected to a delay device, an automatic tape speed control system, the first and second comparators, the first and second electronic keys, outputs connected to a summation device, characterized in that , in order to increase the reliability of the operation by simplifying the device, a block for the absolute value of the signal is inserted into it, the input is connected ny to playback head filter five 0 five a low frequency and an inverter, the absolute value selection block is connected to the inverter through a first comparator connected in series, a low pass filter, a second comparator, the first input of the first electronic key connected to the output of the delay unit, its second control input connected to the output of the second comparator , the first input of the second electronic key is connected to the reference signal bus, its second control input is connected to the output of the inverter, and the output of the summation device is connected to the input of the auto system aticheskogo control skorosti.lenty. Shin Ying (№) p. signal