SU1283839A1 - Autotracking device for video tape recorder - Google Patents

Abstract

The invention can be used in building systems for combining the trajectory of the video head with a recording line with several rotating video heads. The purpose of the device. The output signal from the playback amplifier 1 is fed to the envelope detector 2, which selects the envelope of the reproduced signal. According to the signals of the synchronizing generator .5, the discrete values of the envelope are stored in block 3, and in block 4, the discrete values of the envelope at the working displacement of the video head. The magnitude of this difference is fed to the input of the amplifier-limiter 7, which will not allow to exceed the magnitude of the difference of the amplitudes in the trial and working steps. The adder 9 adds to the current voltage value proportional to the difference of values

Description

The invention relates to instrumentation and can be used in the construction of systems for combining the trajectory of the video head with the recording line in video recorders with the oblique-line recording method with one or two rotating video logs.

The aim of the invention is to improve the speed of the device.

The drawing shows the block diagram of the proposed auto-tracking device for a VCR.

The device comprises a playback amplifier 1, an envelope detector 2, memory devices 3 and 4, a synchronizing generator 5, a processing device 6, a limiting amplifier 7, a test bias voltage source 8, an adder 9, a power amplifier 10, a video head drive 11.

The device works as follows.

The signal from the output of the playback amplifier 1 is fed to the envelope detector 2, which highlights the envelope of the signal reproduced from the recording line. According to the signals of the synchronous generator 5, the discrete envelope values are stored in the storage device 3 at the trial displacement of the video head, and in the storage device 4, the discrete values of the envelope at the working offset

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The amplitude of the limiting amplifier 7 will not allow the difference in amplitude values at the trial and working steps to exceed the value determined by the limiting threshold. The adder 9 adds to the current value of the voltage applied to the video head drive at each overlap point, a voltage proportional to the difference in the envelope values. Therefore, the working step of displacing the video head is proportional to the difference in the envelope values at the working and trial steps.

Claims (1)

Invention Formula An auto-tracking device for a video tape recorder that contains a playback amplifier connected through the envelope detector to the first inputs of two storage devices, the second inputs of which are connected to the first and second outputs of the sync generator, respectively, and the output to the first and second outputs of the processing device, the third input connected to the third output of the clock generator, the voltage source of the test bias and the power amplifier, the output of which is connected to the video head drive, which is Yee has introduced performance in limiting amplifier and an adder prigolovki. The magnitude of this difference is the output of the processing device through the input to the amplifier — the limiting amplifier — the limiter is connected to 7. The output voltage of the amplifier is to the first input of the adder, the second limiter 7, proportional to the difference in the envelope values. If at od40 the input of which is connected to the output of the voltage source of the test offset from the points of displacement in the test or working steps will result in the loss of the reproduced signal, i.e. significant reduction (up to 40 dB) of its am five 0 five 0 The amplitude of the limiting amplifier 7 will not allow the difference in amplitude values at the trial and working steps to exceed the value determined by the limiting threshold. The adder 9 adds to the current value of the voltage applied to the video head drive at each overlap point, a voltage proportional to the difference in the envelope values. Therefore, the working step of displacing the video head is proportional to the difference in the envelope values at the working and trial steps. Invention Formula An auto-tracking device for a video recorder, containing a playback amplifier, connected through the envelope detector to the first inputs of two storage devices, the second inputs of which are connected to the first and second outputs of the sync generator, respectively, and the output to the first and second inputs of the processing device, the third input of which is connected to the third output of the clock generator, the voltage source of the test bias and the power amplifier, the output of which is connected to the video head drive, which is du operating speed has been entered in the limiter amplifier and adder pri5 than the processing device output through limiting amplifier connected to the first input of the adder, the second what is the output of the processing device through the limiting amplifier connected to the first input of the adder, the second the input of which is connected to the output of the voltage source of the test bias, and the third to the third output of the synchronous generator, the output of the adder is connected to the input of the power amplifier.