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定时控制器CH279是上海无线电十四厂生产的一种CMOS中规模专用集成电路。CH279外接32768Hz石英晶体,可获得时间为1s的取样闸门,以及周期为1.00006 s宽度为30μs的R端输出脉冲。该电路可以对输入脉冲进行定时取样(定时1s),输出每秒取出的脉冲串,通过对此脉冲串计数,即可获得每秒脉冲数。这个功能使CH279可以作为频率计数器或转速仪表等的核心部件。另外每秒(略大于1s,但可修正为近似1s)一次的R端输出脉冲,可给其他仪器提供基准秒信号。 CH279为扁平或双列18脚封装。图1所示为CH279引脚排列图。图2为CH279内部方框图。
The timing controller CH279 is a kind of CMOS scale ASICs produced by Shanghai Radio 14 Factory. CH279 external 32768Hz quartz crystal, you can get a sampling gate for a time of 1s, and a period of 1.00006 s width of 30μs R output pulse. This circuit can sample the input pulse regularly (timing 1s) and output the pulse train taken out every second. By counting this pulse train, the pulse number per second can be obtained. This feature allows the CH279 as a frequency counter or speed meter and other core components. In addition, every second (slightly more than 1s, but can be corrected to be approximately 1s) once the R end of the output pulse, other instruments can provide the reference second signal. CH279 is a flat or dual 18-pin package. Figure 1 shows the CH279 pinout diagram. Figure 2 CH279 internal block diagram.