System Receiver Demodulation Circuit Design

Conventional receiver depends on hardware much more. The emergence of software radio results in receiver's renovation. By means of the software radios, any communication function will be performed in the same hardware platform. Due to the limitation of device level, it is impossible to sample RF signal, using special chip to built in the flexible multi-mode and multi-function receivers.This paper first expatiates on the theory of the software radio, discussing the multi-rate digital signal processing, high-speed data acquisitions, digital product detector and digital signal demodulation. We place emphasis on demodulating algorithms of AM, FM, DQPSK in a multi-function receiver. Finally, the circuits are realized with hardware, in order to prove the discussed schemes.