The converter mainly accomplishes changing the c - band rf to intermediate frequency 70mhz , amplifying and gaining . the thesis includes r & d of local oscillator and group - delay equalizer . the thesis overall views the historical development future trend , introduces the theories , applications and characteristics 該變頻器主要完成雙通道c頻段射頻信號到70mhz中頻的變頻、放大和增益控制等功能,本文的主要工作是下變頻器中的本地振蕩器和中頻群延遲均衡器兩部分的研制。