| 摘要 |
Demodulation of standard FM multiplex stereophonic signals is accomplished without using a 38kHz frequency doubler operating in response to the 19kHz pilot tone signal. The first stage of demodulation is accomplished in a first gated symmetrical time gate which is supplied with the composite input signals and is switched in synchronism with the 19kHz pilot signal. The two outputs of this time gate then constitute inputs to second and third time gates which are synchronously switched by a 19kHz signal at quadrature with the signal switching the first time gate. By combining appropriate outputs of the second and third time gates, the demodulated left and right audio information is obtained. |
