Design of Mutiple Signal Generators based on DDS

Abstract

The hardware circuit of the signal generator mainly includes the main control module, DDS module, Voltage-Controlled Gain Amplifier (VCGA) module, keypad module, and LCD display module. The main control module is based on the STM32F103C8T6 as the core controller, and the signal processing section employs the low-power, programmable AD9834 DDS device. The VCGA module utilizes the AD8367 module, providing a controllable 32dB gain range to offer a 20mV/dB output. The waveform voltage amplitude can be adjusted by manipulating the potentiometer on the module and fed back to the oscilloscope. Experimental results demonstrate that the signal generator can produce square waves, triangular waves, sine waves, and sweep frequency waves with stable output waveforms and high resolution. Specifically, the sine wave and triangular wave can be generated within the frequency range of 1kHz to 200KHz, the square wave within the range of 75kHz to 200kHz, and the sweep frequency wave with a sweeping range from 1kHz to 100kHz.