Design and Testing of Laboratory System for Study of Programmable Waveform Generator Based on Direct Digital Synthesis

This paper presents the structure and educational purposes of a laboratory system intended for the study of programmable waveform generators based on direct digital synthesis (DDS). The developed system consists of two basic functional blocks - a programmable waveform generator and a controllable high-frequency attenuator implemented on separate printed circuit boards. The programmable waveform generator is based on the EVAL-AD9833SDZ evaluation board, which is built around a monolithic low-power programmable waveform generator AD9833. The waveform generator functional block producing sine, triangular, and square wave output signals with a fixed amplitude approximately equal to 300 m V (for sine and triangular signals) and frequency range from ~1 Hz up to 1 MHz. The voltage controllable high-frequency (HF) attenuator is synthesized based on monolithic HF four-quadrant analog multiplier AD834 and transimpedance amplifier (TIA) based on current-feedback amplifier (CFA) AD844. The attenuator allows to adjustment of the amplitude of the output signals according to the value of an auxiliary control voltage up to 4 Vp-p. The laboratory system is intended for the practical study of students in the Master's degree program of “Electronics” at the Technical University of Sofia.