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一、抗干扰电路本机采用截止式抗干扰电路。其作用是在大幅度的干扰脉冲到来时,使同步分离电路的输入截止,达到抑制干扰脉冲的目的。没有干扰信号时,抗干扰管BG 10(3DG8)的U_b为正偏置,处于深饱和状态,I_o在负载电阻R_(32)(15K)上产生较大的压降,使下端电压比Q_(16)低,开关二极管BG11(2AP10)处于导通状态,所以全电视信号能顺利通过BG11,传送到同步分离电路和AGC电路去。当负极性的全电视信号中混有干扰信号,并超过同步信号的幅度时,12V电源便经过R_(35)(10K)和BG12(2AP10)对电容C_(29)充电,较大的充电电流使BG10的U_b显著下降,于是BG10从饱和状态转入截止
First, the anti-jamming circuit This device uses a cut-off anti-jamming circuit. Its function is to interrupt the input of the synchronous separation circuit when the large interference pulse arrives, so as to suppress the interference pulse. When there is no interference signal, U_b of anti-jamming tube BG 10 (3DG8) is a positive bias and is in a deep saturated state. I_o produces a larger voltage drop at the load resistance R_ (32) (15K) 16) is low, the switching diode BG11 (2AP10) is in the on state, so the full TV signal can be successfully passed through the BG11 and sent to the synchronous separation circuit and the AGC circuit. When the negative all-television signal mixed with interference signal and exceeds the amplitude of the synchronization signal, 12V power supply will charge capacitor C_ (29) through R_ (35) (10K) and BG12 (2AP10), and the larger charging current U_b significantly dropped BG10, so BG10 from the saturated state into the deadline