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通过试验分析,介绍了解决彩色解码电路同步保持范围窄的方法。在研制彩色投影电视接收机过程中,试制解码电路遇到了一个问题,就是同步保持范围窄的问题。国外可以做到同步范围±200Hz,保持范围±400Hz。当时我们达不到这个指标,并且差的比较多。为此我们做了如下的一些试验分析以求解决这个问题。一、锁相环路的一般原理在PAL制彩色接收机中,为了获得图象信号中的色差信号,必须在接收机中恢复一个基准相位的4.43MHz副载波信号。通常这个信号由一个压控晶体振荡器产生,它
Through experimental analysis, introduced to solve the color decoding circuit synchronization to maintain a narrow range of methods. In the development of color projection TV receiver process, trial decoding circuit has encountered a problem that is synchronized to maintain a narrow range of issues. Foreign synchronization range can be done ± 200Hz, to maintain the range of ± 400Hz. At that time, we did not reach this target, and worse. To do this we have done some experimental analysis in order to solve this problem. First, the general principle of the phase-locked loop In PAL system color receiver, in order to obtain the color difference signal in the image signal, you must recover a reference phase 4.43MHz subcarrier signal in the receiver. Usually this signal is generated by a voltage controlled crystal oscillator, it