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彩电场扫描电路的作用主要是:在场偏转线圈中产生线性良好、幅度足够的场频锯齿波电流,其电路组成大致包括场振荡级(含振荡器和锯齿波形成电路两部分)、场激励级和场输出级三大部分。要求在无场同步信号时,电路能自由振荡工作;当有场同步信号时,电路能被场同步信号同步。根据场输出级电路结构的不同,常见的场扫描电路可分为互补对称型和分流调整型两大类。前者输出级采用的是一对互补对称管,激励信号为锯齿波,在输出级为厚膜集成块的场扫描电路中应用较多;后者输出级采用的是两只同类型的NPN管,它免除了互补对称管在生产中配对较难的缺点,故在输出级为分立元件构成的场扫描电路中应用
The main role of the color TV field scanning circuit is to generate field-frequency sawtooth wave current with good linearity and amplitude in the field deflection coil. The circuit consists of field oscillation stage (including oscillator and sawtooth waveform forming circuit), field excitation stage And field output level three parts. Requirements in the absence of field synchronization signal, the circuit can work free oscillation; when there is field synchronization signal, the circuit can be field synchronization signal synchronization. According to different field output stage circuit structure, the common field scanning circuit can be divided into complementary symmetrical type and shunt regulation two categories. The former output stage uses a pair of complementary symmetric tubes, the excitation signal is sawtooth wave, and is applied more in the field scanning circuit with the thick film integrated block in the output stage. The latter output stage uses two NPN tubes of the same type, It eliminates the disadvantage that complementary symmetric tubes are harder to mate in production and is therefore used in field-scan circuits where the output stage is a discrete component