说明：  1. 测量信号:方波 ； 2. 测量频率范围: 1Hz~9999Hz 3. 显示方式: 4位十进制数显示 4. 时基电路由 555 定时器及分频器组成, 555 振荡器产生脉冲信号,经分频器分频产生的时基信号,其脉冲宽度分别为: 1s, 0.1s 5. 当被测信号的频率超出测量范围时,报警.
(Measuring signal: square wave measurement frequency range: 1Hz ~ 9999Hz display: four decimal 4. Time base circuit 555 timer and divider 555 oscillator pulse signal time base signal generated by the prescaler, the pulse width as follows: 1s, 0.1s when the measured signal frequency exceeds the measuring range, the alarm.)