| 摘要 |
PURPOSE:To improve the S/N whle keeping stereophonic play, by applying AM- detection and rectifycation to an IF signal, converting it into a trigger signal, and inserting high blend at a switch circuit interlocked with this trigger signal to attain automatically high blend. CONSTITUTION:When a desired signal and a disturbing signal having the same or close frequency to the frequency of the desired signal enter an antenna 1, AM and PM modulation are produced in the synthesized wave by the instantaneous frequency difference. This synthesized wave is extracted from an IF amplifier 4, detected at an AM detector 9, amplified at an audio amplifier 11 and fed to a switching transistor 10 by a rectifier circuit as a bias. A high blending capacitor 7 is connected to the transistor 10, the demodulated L, R signals are blended highly, allowing to improve the S/N. |
