| 摘要 |
PURPOSE:To prevent the deterioration of a reproduced signal due to an inverting phenomenon, by inserting a high frequency which turns to a white level into the signal omitted area of the inverting phenomenon part. CONSTITUTION:A feedback circuit including an element which decides the oscillating frequency is provided between amplifiers 4 and 7. The gain of a limiter circuit consisting of diodes 8 and 9 and the amplifiers 4 and 7 is sufficiently large for a period during which the attenuation is eliminated for a carrier signal which causes an inverting phenomenon. As a result, a positive feedback is applied by a feedback circuit to an amplifying transistor (TR) 4 from an amplifying TR7. This limiter circuit is oscillated by the oscillating frequency that is decided by a capacitor 24 and a coil 23. Therefore a signal of a prescribed frequency is inserted into another signal in a period of signal omission. Then a drop of black level, which is due to the omission of signal that produces an inverting phenomenon of a video signal by which a black level changes suddenly to a white level, can be componsated toward the white level side. Thus the drop of the black level is not conspicuous. |
