Novel UNB Transmission System Based On Comb Filter

Ultra-Narrow-Band (UNB) technology can greatly improve the spectrum utilization efficiency, and ease the tension of frequency resources. Therefore it has attracted extensive attention. The topic of this paper comes from the item of Chinese National Natural Science Foundation, and so on. It has an important meaning to theory and realization.After deeply analyzing the power spectrum of UNB, UNB transmission system based on IIR comb filter has been explored in this paper. The characteristic of UNB signal after the comb filter was analyzed. Then information recovery has been performed using optimum receiver. The simulation verifies the feasibility of this program.This paper firstly analyzes the power spectrum of the typical UNB modulation methods. By joint research of the air bandwidth with signal demodulation, this paper clarifies the difference between the definition of signal bandwidth and engineering requirements, and reveals the deep meaning of UNB. Then it analyzes the characteristics of UNB filter, and discusses the feasibility of applying classical filter to UNB transmission system from the perspective of information recovery. To avoid the interference to the adjacent channel, those unwanted discreet spectral lines except carrier should be eliminated before transmission, so this paper design a simple and flexible comb filter. The program can reduce the side-band power effectively, and meet more stringent bandwidth restrictions. The filtered UNB signal maintains the differences of information. As simulation under AWGN channel has showed, the BER performance is close to BPSK.The paper primarily researches the principle and realization of the UNB transmission system, and it is worthwhile to the application of UNB.