Research On DDS Modulator

This paper deals with fundamental principles and characters of Direct Digital Synthesizer (DDS), analyzes the principle of DDS in modulation, also presents various basic schemes to implement GMSIC 4DQPSK and QAM, and makes an initial analysis on their performances. In experiment, 4DQPSK QPSK and QDPSK modulator are designed an achieved. When designing the system, the author uses CPLD to plan ASIC which improves the system reliability, aggregation, maintainability and speed. The research reveals that DDS modulator made up of DDS technique and micro-computer possesses many modulation capabilities and provides a new research way for modulation and demodulation technique.