The Implementation On AMR System Based On OFDM

After considering the special requirements of a AMR system, the article proposed a new design for AMR system, implemented the receiver termininal of the model, based on the new design, with TMS320VC5409. The new design, in which data is modulated in a very narrow band, is based on OFDM and UNB techniques. The new design has the following advantages:First, there are all kinds of interference in the power line. ISI will occur because of the multi-path propagation. The system has immunity to delay spread and can combat interference better because of the introduction of the OFDM technique.Second, using very low carrier is possible due to very narrow bandwidth. The low frequency siginal can trave across the transformer and capacitor used in the power line network. The low frequency signal , only with a low power, can arrive anywhere the power line arrives. Therefore distance is not a problem. The system is suitable for the remote area.At the beginning a model was built and its parameter was decided. After that I verified the model with MATLAB. After the verification of the model, I designed the hardware for the receiver terminal of the system. The transfer terminal of the system is designed by another student.The microprocessor of the receiver is TMS320VC5409. The signal arrived the A/D convertor through the power line, anti-alising filter. The A/D convertor transfer data to TMS320VC5409 by SPI bus. The TMS320VC5409 process received data to detect the training sequence. After coarse synchronization , fine synchronization is abtained and kept. The channel characteristic is abtained by analying the pilot signal. The data after the FFT need to be recorrected according to the channel characteristic. Then the demodulater data is transferred to PC by RS232 interface.