论文部分内容阅读
机器类型 CS-1-1型双通道彩色电视发射机故障现象工作过程中,激励器伴音锁相稳频指示灯闪烁,短则几分钟,长则几十分钟,多出现在播出三小时以后。反映在电视接收机上,伴音出现“嘟嘟”阻塞声。检修过程首先我们用示波器观测“锯齿波”、“取样”、“鉴相”波形,从波形上看不出异样。起初以为是锁相稳频中的W_1调得过于灵敏,反时针调整该电位器,发现伴音频率准确度及稳定性明显变差,故又恢复至原来位置。后来我们怀疑伴音调制器部分(参见附图),故障时,测压控振荡器的静态工作点,(APC通时)发现C_(13)的对地电压为4V,而经过高频阻流圈RFC
Machine Type CS-1-1-type dual-channel color TV transmitter failure phenomenon In the course of work, the incentive sound phase-locked frequency stabilization light flashes, a few minutes long, tens of minutes long, and more in the broadcast three hours later . Reflected in the television receiver, accompanied by “beep” blocking sound. Maintenance process First of all, we use the oscilloscope to observe the “sawtooth”, “sampling”, “phase” waveform, the waveform can not see the same. Initially thought to be phase-locked frequency stabilization W_1 tune too sensitive, anti-clockwise adjustment of the potentiometer and found that sound frequency accuracy and stability significantly worse, it is restored to its original position. Later, we suspect the part of the audio modulator (see the attached figure). In the event of a fault, the static operating point of the VCO (when APC is on) shows that the ground voltage of C_ (13) is 4V, RFC