Research On Wideband IF Digital Receiver And Hardware Realization

Digital receiver applies widely in so many areas such as wireless communication, television, broadcast, radar, satellite communications and so on. Along with the development of the technology of the wireless communication particular the modern modulation and software radio technique, meantime the employ of wireless frequency are more presser, the development of the digital receiver tend towards high performance and high integration. Modern receiver is in pursuit of big dynamic range, good linearity, and high sensitive and so on. That extremely promotes the development of the receiver. Also the requirement of receiver becomes more rigorous. As the name implies, receiver need to improve the linearity, to reduce the distortions rate and bit error rate, and to expend the dynamic range, of course should ensure the signal detect capability precondition.In this paper, at first, the basic theoretics in IF signal processing are researched, such as sampling theory, quartered demodulating technology, filtering and draw-off theory are discussed. Then the problems of system arithmetic, sample rate, and so on, are particularly introduced so the system scheme which was verified can be put forward. Based on these elements, the material design of IF sample and digital down converter based on FPGA is specified. Next, the nuclear chip of IF sample processing is AD9238, whose detailed circuit is introduced. Based on FPGA, the design of digital down converter is quite flexible. The Mixer , realization of Filter and Phase Quantization are introduced. As a new instrument, how to use Quartus II to contrive a filter is ,to take down and test the data are discussed in detail. At last, the whole system is tested, and the test result indicate that the system could work well and the desired requirements could be achieved.