Development Of 1kHz Signal Source

This paper introduces the purpose of 1kHz quadrature signal research,which is mainly used in the field of weak signal detection as an excitation signal for phase-locked amplifiers.The design scheme of the signal source part adopts the most mainstream frequency synthesis technology at present.By comparing the working principles of several frequency synthesis technologies and analyzing their advantages and disadvantages,the direct digital synthesis technology(DDS)is used to develop the signal source.The design scheme of generating quadrature signals is described in this article.STM32 is used as the core to control the DDS special highly integrated chip AD9850 as the signal source.The quadrature signal output scheme is based on the output reference signal of the AD9850 chip.Shift 90°to generate two orthogonal sinusoidal signals.The signal source is mainly divided into the following parts: frequency synthesis module,control module,phase shift module,phase difference detection module,power module,filter.Using the output of test signal sources such as oscilloscopes and spectrum analyzers,the design of this article requires that the maximum allowable error of the frequency of the DDS module is within 0.5%,and the maximum allowable error of the phase of the phase-shift module is within 0.5%.The results meet the system indicators.