早期移频激励器的性能指标已无法满足目前短波移频电报通信的要求,特别是自激振荡器的频率稳定度和准确度很难保证.因此,必须采用新的移频方法,晶体直接移频的方法是其中的一种.一、电路原理晶体直接移频的方法比较简单,如图1所示为2.8兆赫晶体直接移频振荡器原理图.接入一个控制电容器C_u利用开关二极管D的短路或开路,控制晶体串联 The performance of early frequency shift exciters can not meet the current shortwave frequency shift telegraph communication requirements, especially the self-excited oscillator frequency stability and accuracy is difficult to guarantee.Therefore, we must use a new frequency shift method, direct crystal shift Frequency method is one of the.First, the circuit principle of the crystal direct frequency shift method is relatively simple, as shown in Figure 1 for the 2.8 MHz crystal direct frequency oscillator oscillator diagram.Cu access to a control capacitor using the switching diode D Short circuit or open circuit, control the crystal series