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9.晶振与定时电路县站和公社放大站的晶振与定时电路是相同的。晶体振荡器电路如图55所示。BG_2的输出通过100 kHz晶体反馈到BG_1的输入端,晶体相当于串联谐振电路,阻抗很小,故构成强烈的正反馈,振荡输出接近方波。BG_3是射极跟随器,用以减轻了负载对晶振的影响。
9. Crystal and timing circuits County stations and communes to enlarge the crystal and timing circuits are the same. The crystal oscillator circuit is shown in Figure 55. The output of BG_2 is fed back to the input of BG_1 through a 100 kHz crystal. The crystal is equivalent to a series resonant circuit. The impedance is very small and thus forms a strong positive feedback. The output of the oscillation is close to a square wave. BG_3 is an emitter follower to reduce the impact of the load on the crystal.