Hardware Research And Realization Of IF Digital Receiver

The performances of traditional radio receiver depends on hardware heavily with poor adaptability and recognition ability to the signals.The digital receiver can not only meet the common demands of receiver but even realize the function of panoramic recognition and reception.It is necessary to place AD converter to the receiving antenna as close as possible to convert the analog signal to digital signal.The design of IF digitization is mostly adopted in digital receiver system since it is difficult to sample RF signal directly.A digital IF receiver is designed in this paper according to the jamming system requirements in actual situation.IF signal is sampled in AD directly after converting.Then the sampling data is transmitted to the host computer after digital down-conversion and digital demodulation.The modular design is used in the system,which is composed of channel module,digital signal processing module and control module.The IF signal is obtained from channel module by filtering,amplifying and mixing the receiving signal.Then it is transmitted to digital signal processing module.There are IF analog signal demodulating and high-speed AD sampling circuits based on FPGA in digital signal processing module which achieve the functions of analog-digital converting,digital orthogonal down-conversion and filtering extraction,while DSP completes the functions of digital demodulation and sampling judgment of baseband signal data.The control module realize the functions of system control,data storage and interaction with the host computer.The frequency synthesizer and digital signal processing module are mainly designed in the paper.The modules are verified and tested in the detection interference system.It shows that the designed IF digital receiver meets the demands of the system.