摘要
Abstract
DX200 medium wave transmitter's control board has a stepping sequence control function when the transmitter starts. Also it monitors the power amplifier unit and gives protective response to the faults of internal and external parts, etc. In order to make every control circuit coordinately work on time, we have adopted a 555 in-tegrated timer which constitutes an astable free-running multivibrator with peripheral resistance and capacitance. The multivibrator generates an 8 KHZ clock signal. Frequency divider made with 74 hc161 synchronous counting units produces 4 KHZ, 128 HZ, 64 HZ, 16 HZ and 1/64 HZ, sends them to each PAL and programmable logic de-vices, and then provides corresponding control. Based on 555 integrated timer and 74 hc161 synchronous counter, the paper introduces in detail the structure and internal principle and their functions, and elaborates the generating principle of the transmitter control board's clock circuit.关键词
555集成定时器/74HC161同步计数器/时钟电路Key words
555 Integrated Timer/74 HC161 Synchronous Counter/Clock Circuit分类
信息技术与安全科学
