The Technology Of Digital IF Receiving Based On DSP

Along with the advancement of electronic and computer's technology, especially the increase of the digital signal processor's speed, the digital signal processing technology is more and more important in receiver. Digital receiving technology is widely used in the field of radar, weather, Software Radio and so on. This receiver has strong universal, and all or most of the signal processing are realized by DSP program. The core of digital receiver is DSP. The DSP technology changes the hardware framework of traditional receiver, the interface of analog and digital of intermediate frequency is with a pair of high speed ADC and DAC, the core is a high speed DSP which is used to finish signal decimation, filter, demodulation etc.The main aim of the digital IF receiving is to construct a opening, normative, blocking hardware platform, and make various functions by software, for instance modem types, data format, encrypt pattern, communication protocol etc. the digital IF receiving system has good performance in generality and flexibility. It is very convenient to inter-system connect and update.The author analyses the principle of digital receiving technology, combines actuality, and brings forward the scheme. The main content is as follows: It introduces digital IF receiving structure, brings system scheme. After digital down-converter (DDC), it changes the radio frequency to IF signal. At the same time, digital filter replaces analog filter after ADC, which enhances the system flexibility and filter selectivity. It analyses the core of digital IF receiving--- DDC, brings DDC structure which is group of digital mixer, Numerically Cont rolled Oscillator and LPF , and which is the core and most complex operation of digital IF receiving. It realizes digital mixer, NCO, CIC and HB filters.It introduces a novelty method which combines DSP and MATLAB. CCSLink connects the two environment.ETTIC6000 integrates DSP technology, it can create DSP executed code from Simulink model.It is research significance at last, and combines the lately DSP technology, realizes digital IF receiver. All digital signal processing is finished by software, it can realize different functions by choosing different modules, and the software can not only update easily, also reduce cost.The digital receiving technology is non-stopping prefect, especially combines Real-Time Workshop and DSP which has much development space. The study tries to make some positive significance to digital IF receiving which is base DSP.At present, digital receiving technology is a studied trend all over the world, digital technology and processing capability are stronger. Digital IF receiving technology and DDC based DSP, other with the soft arithmetic based MATLAB and DSP, has abroad background and merit.