四选一数据表决器，ABCD四选一，选择一个输出端口输出所要的电平。实现数据表决-Four data select a voting machine, ABCD four-pick one, choose an output port to the output level. Data division

数字频率测量器，脉宽测量器。可测量多种频率波形的脉宽。-Digital frequency measurement device, pulse width measurement device. Measurement of the waveform of frequency pulse width