Self-adaptive single-frequency narrow-band interference trapped wave filtering device and double-frequency filtering equipment

Abstract

The invention discloses a self-adaptive single-frequency narrow-band interference trapped wave filtering device and double-frequency filtering equipment. The self-adaptive single-frequency narrow-band interference trapped wave filtering device comprises a self-adaptive single-frequency trapped wave filter, a single-frequency interference signal frequency estimating and updating unit, an input signal and interference signal energy estimation unit and a self-adaptive single-frequency trapped wave filter output selection device. The double-frequency filtering equipment comprises two self-adaptive single-frequency narrow-band interference trapped wave filtering devices which are in cascade connection with each other and an auxiliary trapped wave filter. The self-adaptive single-frequency narrow-band interference trapped wave filtering device is expanded to a self-adaptive double-frequency wave trap and has a flexible hardware structure to achieve different functional combinations, that is, one or two single-frequency narrow-band interference signals are removed in a self-adaptive mode, so that the deviation of an estimated value of the narrow-band interference frequency is small, and the wave trapping effect is good.

Description

technical field [0001] The present invention relates to the technical field of communication methods, systems and equipment, in particular to an adaptive single-frequency narrow-band interference notch filter device realized by an adaptive notch filter based on a lattice IIR filter structure, and the above-mentioned adaptive single-frequency A dual-frequency filtering device composed of a narrow-band interference notch filtering device. Background technique [0002] Power line communication (Power line communications-PLC) is a communication system that uses power lines as the transmission medium. Classified as broadband, high-speed, short-distance applications (referred to as broadband PLC technology). The narrowband carrier works in the 3kHz-500kHz frequency band. Under this carrier frequency allocation, the communication speed is generally below 1Mbps. Currently, the common narrowband PLC standards in the world are IEC61334, PRIME, G3-PLC, ITU G.9955 / 9956 and IEEEEP1901....

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Problems solved by technology

[0006] US Patent US6,976,044B1 (Mahdl T.Kalani, Narrowband Interference Canceller for Wideband Communication Systems) is based on the direct type IIR structure, which has the disadvantages of high implementation cost, slow convergence speed, and easy convergence to local minimum

In addition, this patent does not mention the algorithm of the adaptive dual-frequency notch filter

[0007] Shotaro et al. (Shotaro Nishimura et al, A Lattice-based Adaptive IIR Notch Filter and Its Application to FSK Demodulation, pp.586-589, ISCAS2000, May28-31, 2000, Geneva, Switzerland) proposed a lattice IIR ANF structure , but this scheme uses different gradient signals to achieve self-adaptation. The amplitude of this gradient signal is changed by the frequency of the narrowband interference signal, which affects the convergence speed and accuracy.

In addition, this document does not mention the algorithm of adaptive dual-frequency notch filter

[0008] Cho et al (N.I.Cho, et al, On the Adaptive Lattice Notch Filter for the Detection of Sinusoids, IEEE Trans on Circuits and Systems-II Analog and Digital Signal Processing, Vol.40, No.7, July, 1993, pp.405 -416) proposed several different multi-frequency signal notch filter structures, although this scheme also uses the lattice IIR ANF structure, but it has deviations and the convergence speed is average

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