Research Of Receiving Technology Based On RF Bandpass Sampling

Nowadays, as analog broadcasting switching to digital broadcasting, the analog radio isgradually phased out. But the traditional AM broadcasting with low cost and strongsurvivability is non-alternative in the case of sudden-onset natural disasters.Software-Defined Radio technology can solve issues of receiver compatibility in the stageof the coexistence of analog and digital broadcast very well. The bandwidth of AM signalis only9kHz, and AM signal can be sampled based on bandpass sampling theorem.That is,using narrow-band filter to select and amplify the desired signal, then sampling the signal.This SDR structure based on RF bandpass sampling, which is closed to ideal SDR, isrelatively easy to implement.In this paper, according to the research of receiving technology based on RF bandpasssampling, a AM receiver based on RF bandpass sampling is designed and developed as aplatform for implementation of AM demodulation function IP core.And the IP core can beused to facilitate design reuse, shorten design time.Firstly, the paper introduces the technology of RF bandpass sampling and simulates thetechnology and the algorithm of AM demodulation. Secondly, the paper designs thehardware of the receiver, including narrow-band electrically tunable filter, low noiseamplifier and AGC circuit, A/D and D/A circuit, FPGA processors and the interface circuit,audio amplifier and power circuit. Thirdly, the software of the receiver system is designedand completed, which mainly includes the control section of electrically tunable filter andthe AM demodulation IP core. Finally, the paper presents system testing and debugging toverify the correctness and feasibility of the design.