Wideband Waveform Generator

This circuit is designed to provide a wideband digital sine wave signal source. Its main feature is that because it synthesises the signal in 32 steps, no low-pass filter is required to suppress the odd harmonics. A well-known method for synthesising a sine wave under control of an input frequency is to apply a low-pass filter to a square wave of the same frequency. Along with the fundamental, this includes odd harmonics. After filtering out these parts of the signal we are left with a clean sine wave at the desired frequency. Unfortunately, the corner frequency of the lowpass filter limits the usable range of frequencies.