音频A/D转换芯片的输出增益和失真度是无法直接测试的，需要对输出的数字信号进行解析还原成模拟信号方可以进行测试。有些A/D产品输出的数字信号可以直接进行解析还原成模拟信号，而有些则需要先对输出的数字信号进行处理。以某A/D转换芯片为例，首先利用了六反向施密特触发器74HC14和8位串入并出移位寄存器74HC164对输出信号时序进行转换，然后采用stm32f103对时序转换后的数字信号进行解析，最后将解析后的数据传送至上位机，最终实现了对该A/D转换芯片输出增益及失真度测试的目的。%The output Gain and Total Harmonic Distortion (THD) of Audio A/D converter chip cannot be tested directly. The appropriate way requires analysis and reduction of digital output signal into analog signal which can be tested. Some output digital signal from some product can be transformed into digital signal directly, some others needs digital signal processing for transformation. This article introduces a process to treat the digital output signal into analog signal, with the timing sequence transformation using 14 Hex Inverting Schmitt triggerand 74HC164 8-bit Serial-in/Parallel-out Shift Register on top of sampling, analysis and reduction using stm32, which will be transmitted to host computer.
展开▼
