A pre-distortion method to reduce DDS spurious

Abstract

We present a pre-distortion method for suppression of direct digital synthesizer (DDS) spurious. The method has been implemented in a field programmable gate array (FPGA) architecture with the FPGA generating the DDS waveform and controlling a high speed digital to analog converter (DAC). A generic approach is provided, followed by a detailed example. Measured data will be shown for a continuous wave (CW) case and a linear frequency modulated (LFM) waveform. It will be demonstrated that a practical calibration can achieve over 20dB spurious improvement.