论文部分内容阅读
彩色电视机在使用过程中常因电源电压波动、机内温度升高等因素,使调谐好的频率发生漂移,造成图像、色彩和伴音不稳定现象。为此,在新型彩色电视机上一般都加有一个AFC(自动频率控制)开关。接通该开关(置于ON位置),电路中的自动频率控制系统就会将频率偏离量变成直流电压去控制高频头中的调谐频率,在一定的偏离范围内,可使电视机始终保持在正确的调谐频率上。但在手工调谐时,如果频率偏
Color TV in the course of the power supply voltage fluctuations often occur, the temperature inside the machine and other factors, the tuned good frequency drift, resulting in images, colors and sound instability. For this reason, an AFC (Automatic Frequency Control) switch is generally added on the new color television sets. Turn the switch (placed in the ON position), the automatic frequency control system in the circuit will be the frequency deviation into a DC voltage to control the tuner in the tuner frequency, within a certain deviation from the TV can always Stay tuned to the correct tuning frequency. But in the manual tuning, if the frequency of bias