译码器在数字系统中有着广泛的应用,笔者在门电路测试仪中,将译码器作为测试信号源应用。下面作一介绍。我们知道,作为门电路的功能测试,其测试信号有下述特点: 1.对于与门(与非门、异或门),依次给输入端加“0”信号,其余输入端加“1”信号,若门电路输出为低电平(高电平),说明输入端无开路故障,否则,说明输入端有开路故障;如果门电路所有输入端都加“1”信号,若输出为高电平(低电平),说明输入端无短路故障,否则,输入端有短路故障。 2.对于或门(或非门),依次给输入端加“1”信号,其余输入端加“0”信号,若门电路输出为高电平(低电 Decoder in the digital system has a wide range of applications, the author in the circuit tester, the decoder as a test signal source applications. Here’s an introduction. We know that, as the function test of the gate, the test signal has the following characteristics: 1. For the AND gate (NAND gate, XOR gate), turn “0” signal to the input end and “1” Signal, if the output of the circuit is low level (high level), it indicates there is no open circuit fault in the input terminal. Otherwise, it indicates that there is an open circuit fault in the input terminal. If all the input terminals of the circuit are added with “1” signal, Flat (low), indicating no short-circuit fault input, otherwise, the input short-circuit fault. 2. For OR gate (NOR gate), add “1” signal to input end in turn, add “0” signal to other input end. If the output of gate circuit is high level