| 摘要 |
PURPOSE:To improve performance and to reduce cost by detecting a decrease in the high frequency range of a playback signal directly, and then generating a correcting signal. CONSTITUTION:A playback mixed signal 1 from a pickup 4 is supplied to a cross- modulation correcting circuit 5 and a band-pass filter 9. The band-pass filter 9 separates an FM audio signal from the mixed signal 1 and the separated signal is passed through an FM modulating circuit 10 to obtain an audio signal 3. The circuit 5 corrects the cross modulation of the input 1 by a correcting signal from a DC amplifying circuit 19. Its output is passed through a band-pass filter 6 to separate an FM video signal, which is supplied to a frequency characteristic circuit 7, where uniform frequency characteristics are obtained by a correcting signal from a DC amplifying circuit 19. Its output is passed through an FM demodulating circuit 8 to obtain a video signal 2. The video signal of the circuit 8 is supplied to a multiplying circuit 15 through a band-pass filte 11 and an amplifying circuit 12. The FM signal from the filter 9 is passed through a phase shifting circuit 14 and then multiplied by two input signals at a multiplying circuit 15, and the resulting signals are supplied to correcting circuits 5 and 7 through a low-pass filter 16 and amplifying circuits 17 and 19. Thus, a low-cost, high-performance aperture characteristic correcting device is obtained. |
