DDS signal generator (based on AD9833 module and 51 microcontroller)

This project implements the following functions:

1. Output sine wave, square wave, triangle wave adjusted by buttons

2. Frequency 100Hz-1MHz adjustable

3. The amplitude is adjustable from 0-5V (actually it cannot reach 0V, but is close to 0)

4. Frequency and amplitude are step-adjustable (step 1-10000), with reset button

Details: DC head 5V power supply, LCD1602 and the studs of the entire board are M3 models

Key Description:

+/-: plus/minus button, long press

SET: Setting button, f is to set the frequency, A is to set the amplitude, B is to set the step

WaveForm: waveform setting button

Instructions for use: Burn the hex file to the microcontroller

This project is a high-frequency signal generation module for a respiratory signal measurement circuit, and that module requires a 10*10cm PCB board, so this PCB board has not been compressed. If there are any deficiencies, please feel free to raise them.

You are also welcome to follow me and I will continue to share in the future.

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Since the amplification factor of the AD9833 module is 5 times, sometimes the amplitude of the waveform will decrease if the frequency is too high, so I followed the official manual of the module and made a V2.0 version with adjustable amplification factor.

The following functions are added based on the previous version:

1. Add an emitter follower and output it from the PGA1 port to improve the load capacity.

2. Add the manual adjustment magnification function, using a 3296W sliding rheostat (set tone 20KΩ), which can theoretically amplify the original signal 0-20 times and output it from the VOUT1 port

3. Add SMA interface to output PGA signal

4. Add 5V voltage output