| 摘要 |
PURPOSE:To increase the S/N, to reduce the number of components, and to simplify the circuit pattern, by connecting a peaking circuit between input and output terminals of desired amplifying stages and providing a negative feedback adjusting means. CONSTITUTION:No control signal is applied to a transistor (TR) 27 at the standard speed. A signal reproduced by a playback head is subjected to equalization matched to the standard speed at a playback equalizer 1. On the other hand, a low-speed switching signal from the playback device switches the TR27 to ON. Thus, the negative feedback amount at high frequencies of the playback signal reproduced at the playback head is reduced, thereby the amplification gain of an amplifier 21 of the 1st stage is increased. According to the increase in the amplified gain, the peaking frequency of a peaking circuit 4 is lowered and the damping amount of the said peaking circuit can be reduced. Thus, the S/N can be increased. |
