The Designs And Realizes Of A Kind Of 10MHz To 10GHz Signal Source

Signal source is an instrumentation that is commonly-used in institutes of scientific research and labs as well as is widely employed in Electronic Engineering, Communication, Automatic Control, Scientific experiments and other related fields. As radio techniques are widely employed, the exclusive signal sources on broadcast, TV, radar, communication, etc. for special purpose are constantly emerging. The broader bandwidth is a salient feature of military microwave, in which microwave transceiver often uses superheterodyne structure, therefore, double-conversion is generally used to move spectra, while local Oscillator is an important part of transceiver. In scientific research and production, 2 or 3 signal sources are commonly required for providing LO and frequency signals in order to debug and test a number of up-and-down frequency inverters. For the purpose of catering for the needs of microwave signal sources in scientific research & product tests and after-sale service, this thesis designs and realizes a kind of 10 MHz to 10 GHz signal source.The thesis makes a theoretic analysis on techniques of Phase Locked Loop(PLL) and Direct Digital Synthesizer(DDS). Based on the analysis and actual demand, the author selects a program of DDS driving PLL synthesizer, as employs advantages of DDS high-resolution, PLL high-frequency synthesizer and broad bandwidth, thus makes an achievement of frequency synthesizer of small step, broad band and low phase noise.This thesis uses the mode of DDS driving PLL synthesizer and makes main achievements as follows:Based on the fundamental theory of DDS and PLL, it puts forward a program of realizing small step by DDS driving PLL and lowering system phase noise by raising DDs reference clock of phase noise.It designs all parts of electric circuits in the program and makes them come true, also makes corresponding calculation on theory and software simulation.It gives some related tests on the achieved signal sources. The test results prove that signal sources realize low phase noise, broad bandwidth and high-frequency resolution.This thesis has a certain referential significance in researching and production of small-step and low-phase–noise broadband frequency synthesizer, of which achievements have already been used in actual projects.