A Method Of Amplitude-Frequency Characteristic Compensation About DDS Signal Source

DDS (direct digital synthesis) is widely applied in signal generator. In this paper, amplitude-frequency characteristic of DDS signal after D/A conversion (DAC) was analyzed. Then a method for improving amplitude-frequency characteristic was put forward. The method is based on characteristic of LC parallel circuits that signal can be amplified at resonance frequency. By this method, amplitude attenuation caused by DAC is compensated; amplitude frequency characteristic of DDS signal is improved. The experiment results indicate that amplitude flatness of arbitrary waveform generator increases about 2 dB at 0 Hz-40 MHz.