General-purpose Digital Downconverter Research And Application

In this paper, we summarize the basic principles of the IF (Intermediate Frequency) digital technology and detail the design and realization of a IF digital system.Digital IF receiver plays one of the most important parts in the modern communication system, to realize the whole digitization of the receiver has become an important matter in the implementation of modern communication systems. With the fast development of the Software Radio technology, both in the communication system and in the radar system, the digital IF digital receiver is expected to be designed based on the Software Radio technology in order to define the function of the hardware by the software, which can improve the flexibility and the reliability of the system greatly. The main objective of this paper is to study the digital IF technology thoroughly and to discuss the design of the realization so as to find the basis for the development of the IF digital receiver.The main works of this paper are presented as follows:Complete the design and simulation of the system;Complete design of the circuit and the hard-ware realization of the whole system;Complete design of the modules in the system and the software programming of these modules;Realize demodulation of AM and FM signal; the waveform and test results of the demodulation have been given;Realize digital orthogonal demodulation; the method and results of amplitude consistence and phase orthogonality of the I,Q signal have been given;...