Direct digital frequency synthesis function generator

Aiming at high integration and low cost requirements at function generator module of integrated test instrument,a digital function generator was designed based on the direct digital frequency synthesis(DDS) technology.It consisted of three parts-microprocessor systems DDS system,analog channel.Phase accumulator and the ROM stores waveform table in field programmable gate array(FPGA) were designed,to change the wave frequency by load frequency control word,to achieve the digital part of DDS system,and the MCU of W77E58 was microprocessor systems of the function generator.The test results indicate that the design of the function generator can produce sine wave,square wave and triangular wave,and accords with the system requirements on the waveform amplitude,frequency,precision of the indicator.