The Design And Realization Of Software Radio Digital Monitoring Receiver

Receiver is a key part of radio communication system. The traditional radio receiver suffers simple function and poor signal processing. Hardware plays an important role in the traditional radio receiver world so its expandability is limited. But Software Defined Radio (SDR) is more advanced than the traditional. It is characterized of module and standard simple hardware. In SDR, it adopts Digital Signal Processing technology and its design theory is to realize radio communication function through upgrading application software. The key technology in SDR include wideband/multiband antenna, wideband A/D conversion, DDC(Digital Down Converter) technology, DSP technology and real-time operation system etc.The emergency of SDR brings abort the renovation of receiver. Its working principle is to sample RF signal first, then load different software to DSP signal to obtain different waveform modulation and demodulation. Owing to the limited component level, currently we cannot directly sample RF signal instead of sampling wideband IF (intermediate frequency). Moreover, the receiver is composed of special chips to strengthen its powerful function. Such kind of receiver meets the communication requirements of modem military forces, in a word, interoperability and compatibility. This design scheme also makes maintenance cost reduce considerably and development cost decrease.In my design of "IF digital receiver in Software Defined Radio",the center frequency is 10.7MHz, IF modulation signal with 10MHz bandwidth. The data flow is sampled by AD ,then processed by DDC (Digital Down Converter) GC1012B and DSP(digital signal process)the data, After the carrier signals are digitally demodulated, then carried through by FFT signal-processing algorithms.The DSP+CPLD architecture is employed to construct the hardware platform for running the supporting software. CPLDs are used as logic controllers,while DSPs are used to implement FFT signal-processing algorithms,. Software is consisted of signal processing procedures in transmitter and receiver: The software also includes the hardware interfacial routines, such as routines interfacing to AD converters, UART,DDC etc.