JPS5483816A - Digital signal generator - Google Patents

Abstract

PURPOSE: To generate digital signals, which are free from deterioration in discriminating capacity during the recording and reproducing processes of a VTR or the like, by reducing the amplitude of the digital signals to be superposed upon video signals and to be modulated within a preset range.

CONSTITUTION: The aural signals to be fed to a digital signal generating circuit 1 are converted by an A/D converter 6, which is synchronism with the clocks of a recording system reference signal generator 7, and a memory circuit 8 into digital signals, which are fed to a level setting circuit 10 while being supplied with prescribed check characters. In this circuit 10, white and pedestal levels wl and dl of the usual video signals are preset so that the amplitude of the digital aural signals generated by the circuit 10 becomes smaller than the difference between the levels wl and dl and so that they are superposed upon the amplitude reference signals from a white reference signal generator 11 and recorded in a VTR 2. As a result, even if over- or under- shoot O or U is generated during the modulation of the complex recording operation of the video signals during the video period to the VTR 2, there can be produced the digital signals which do not exceed the white or pedestal level and which are free from deterioration in discriminating capacity. The reproduction can be effected similarly.

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