[Zhejiang University of Science and Technology Electrical Competition] Various Waveform Generators (Question E)

## This project won the third prize in the 5th Zhejiang Sci-Tech University Electronic Design Competition

#### Team number: ZSTU036

#### Team members: Ren Juntao, Ni Zhaoyan, Li Zifan

#### Instructor: Lu Jun

##《 School-Level Electronic Design Competition" Design Summary Report

Topic Requirements:
1. Basic requirements****
(1) A single +10V power supply is required, using a power management chip to generate multiple voltages such as -10V, 5V, 3.3V, etc., which can provide Powered by a variety of waveform generators; (20 points)
(2) Use the 74LS74 trigger to generate a square wave with an adjustable output frequency of 10-20kHz and an output voltage amplitude of 3V peak-to-peak. At this time, the trigger input signal is generated by the signal generator ; (15 points)
(3) Use the 74LS74 trigger to generate a triangular wave with an output frequency of 5-10kHz adjustable and an output voltage amplitude of 3V peak-to-peak; (15 points)
(4) Generate an output frequency of 10-30kHz adjustable and an output voltage A sine wave with a peak-to-peak amplitude of 3V; (15 points)
The above output waveform is required to have no obvious distortion, the frequency and output voltage error is less than 5%, and the load resistance of each stage is 1KΩ.
 2. Use part ****
(1) It is required to use a microcontroller to output a square wave of 20-50kHz, and the peak-to-peak output voltage amplitude is 3V; (10 points)
(2) The frequency of the square wave generated by the microcontroller can be determined by "+", "- "Button setting; (10 points)
(3) The square wave frequency set by the microcontroller and the sine wave frequency output by the waveform generator can be displayed on the LCD (; 10 points)
(4) Design and make the PCB board by yourself (no process restrictions) (5 Points)

The output frequency is adjusted by the microcontroller as a whole. The waveform circuit of each module only needs to consider the voltage amplitude issue. The microcontroller outputs a square wave through the 74LS74 two-divided frequency to output the first required square wave. The four-divided frequency is connected to the integration circuit to generate a triangle wave, and then Connect amplification and filtering circuits to generate sine waves. In this way, the minimum frequencies of each waveform required in the question correspond one to one. There is only a problem that the upper limit of 25kHz for sine waves cannot meet the requirement of 30kHz. The microcontroller codes are displayed in the design report in the attachment.
![MCU.png] ![74LS74.png] ![Integral circuit.png] ![Power supply.png]