The Design On Signal Generation And Control Module Of Synthesized Signal Source

The Synthesized Signal Source plays a vital role in contemporary electronic communication system. It not only determines the performance of one system, but also is the indispensable part of the Measure, Medical, Radar and other areas. If necessary, the Synthesized Signal Source may output any frequency within bandwidth, and its signal power can be continuously adjustable within a certain range. Therefore, the frequency synthesis, power control is the basic and crucial techniques of the Synthesized Source develop. In some Synthesized Source has frequency modulation, amplitude modulation, pulse modulation and other auxiliary functions. Therefore, the modulation technology is also an important technology of Synthesized Source.Frequency synthesis technology is the most important factor in determining the quality of Synthesized Source output spectrum. It also affect the realization of modulation functions. Therefore, how to use frequency synthesis technology to draw up a reasonable frequency synthesis scheme is the crucial and difficult part of the design. Power control is mainly to achieve wide range of signal power dynamic adjustment. How to achieve the lowest power output and reduce signal distortion due to amplification is the difficulty of power control.The main task of the Synthesized Signal Source is to generate a sinusoidal signal with 100 Hz resolution of 5kHz~1.1GHz frequency range. Its output power can be continuously adjustment in-110~+13dBm. What’s more, it has frequency modulation, amplitude modulation, pulse modulation. The mainly design of the hardware system consists of three modules, which is, frequency synthesis module, signal conditioning module and control module. The main work of this paper include the following:(1) Design and implement a frequency module:Under the promise of the outputfrequency range, resolution, and the frequency switching time, using mixer,multiplier to develop a reasonable frequency synthesis scheme in thecombination with several major frequency synthesis technologies; In addition,design a reasonable segmented filter module which is to suppress harmonicsignal.(2) Design and implement a output power control module:Using cascadedamplifiers to meet the maximum output signal power of +13dBm; Using CNCattenuator, fixed attenuator and isolation between attenuation andamplification to approach the minimum output power and the adjustment ofdynamic range.(3) Design and implement the control module:Using ARM and FPGA to achievethe control of entire hardware platform. Achieve the circuit design and timingcontrol of modulation functions. And design the power module to supply theentire hardware system.The test results of the Synthesized Signal Source is given in the last part of the paper. Finally, the paper sum up the achievements and insufficient of the design and propose improvements.