这是一个电子设计大赛初赛的一个作品源代码。芯片为单片机AT89C52，C语言。作用是测试输入的低频交流信号，可以测量1Hz~60KHz的范围，最大为5V的峰峰值方波信号。硬件中，通道是用模拟开关芯片选择不同的放大倍数。-This is the source code for a work of an electronic design contest preliminaries. Chip microcontroller the AT89C52, C language. Role of the test input of the low-frequency AC signal, can measure the range of from 1Hz to 60kHz, the maximum of 5V peak-to-peak square wave signal. Hardware, the channel is the analog switch chip select different magnifications.