本装置适用于各种没有自动静噪功能的黑白、彩色电视机。电路如图1所示。工作原理:当有符合f_0的信号从锁相音频译码器集成电路LM567(内部锁相环振荡器的中心频率是f_0,由5、6脚的外接阻容元件决定)第3脚输入时,内部接于第7、8脚之间的模拟开关将导通,否则其截止。其工作过程:当黑白、彩色电视机收到电视信号时,同步分离级输出的行同步信号经R1、C1输入到LM567的第3脚,由于其频率与f_0中心频率基本一致,于是 This device is suitable for a variety of black and white, color TV without automatic squelch function. Circuit shown in Figure 1. How it works: When there is f_0 signal from the phase-locked audio decoder integrated circuit LM567 (internal PLL oscillator frequency is f_0, 5,6 feet by the external RC components) input pin 3, The internal analog switch connected to pins 7 and 8 will be on, otherwise it will be off. The working process: When the black and white, color TV receiver TV signal, the sync output of the sync line sync signal through the R1, C1 input LM567 pin 3, because of its frequency and f_0 center frequency is basically the same, then