Research Of Fast Wideband Frequency Synthesizers

Radar and Electronic War technology has been booming for over a decade. The research in doppler Radar, ECM, ECCM system is tremendous. The frequency synthesizer is a key component in these systems. The switching time of frequency synthesizer determines how fast the communication channels can be switched and how fast the system can be turn on. A frequency synthesizer can be designed with a high quality of phase noise or a fast switching time, but these two quantities are not compromised. The design of fully integrated, fast switching time frequency synthesizes with low noise/spurs is an ever-lasting challenge in Radar and ECM systems.This paper describes the operating theory of Direct Analog Synthesizer and its phase noise, spurs, as well as its resolution, reviewing the methods that speed-up the switching time of synthesizers. This paper process a novel fast, wide band, low phase/spurs, high resolution frequency. In this paper, after using a direct analog synthetic techniques, we have implemented an wideband frequency synthesizer with a fast switching time and an excellent phase noise. The synthesizer includes a novel DDS (Direct Digital Synthesizer), a frequency divide module, and a frequency Triple-Mixer module. The measured results demonstrate that the wide band high resolution synthesizer can speed up the switching time less than luS in the whole frequency range. The synthesizer avoided the tradeoff between the speed and the phase noise and spurs. The measurement phase noise of the DAS is-105dBc/lKHz, and the spur is less the-60dBc with all the frequency range.