[Tianjin University of Technology] Differential amplifier circuit tester Xunmeng

This differential amplifier circuit tester mainly consists of three parts: differential signal source, triode differential amplifier circuit and measurement display. The signal source part mainly generates the sine wave signal through the AD9833 chip and the digital potentiometer, then generates a differential signal through the inverter, integrates the DC common mode signal and the AC differential mode signal through the adder, and realizes the voltage amplitude and frequency through the key control of the microcontroller. step. Common mode signal voltage range: 0V~1V, 10mV step, differential mode signal voltage range: amplitude (0-100mV), 10mV step; frequency range 100Hz~1MHz, 100Hz step, parameter index error does not exceed 5mV. It is required to measure the voltage amplification factor of the amplifier at 1KHz. The measurement part measures the peak-to-peak value of the potential through stm32 programming and calculates the ratio to obtain the amplification factor. Finally, effective data such as voltage value and amplification factor are displayed on the LCD screen. Considering that the amplified voltage amplitude is too large and has a large DC offset, which may exceed the measurement range of the microcontroller, devices such as transistors are used for voltage reduction processing, and the processing part is compensated in the test program.