Adaptive single-frequency narrow-band interference notch filtering device and dual-frequency filtering equipment

Abstract

The invention discloses an adaptive single-frequency narrow-band interference notch filtering device and dual-frequency filtering equipment. The adaptive single-frequency narrow-band interference notch filtering device includes: an adaptive single-frequency notch filter, single-frequency interference signal frequency estimation and Update unit, input signal and interference signal energy estimation unit, and adaptive single-frequency notch filter output selection device; the device includes two mutually cascaded adaptive single-frequency narrow-band interference notch filter devices and an auxiliary notch filter. The present invention is extended to the self-adaptive dual-frequency notch filter, and has a flexible hardware structure to achieve different function combinations: adaptively remove one or two single-frequency narrow-band interference signals, the narrow-band interference frequency estimation deviation is small, and the notch effect it 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 InterferenceCanceller 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 values.

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 NotchFilter and Its Application to FSK Demodulation, pp.586-589, ISCAS2000, May28-31, 2000, Geneva, Switzerland) proposed a lattice IIR ANF structure, However, this scheme uses different gradient signals to achieve self-adaptation, and the amplitude of the gradient signals is changed by the frequency of the narrowband interference signal, thus affecting 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 ) proposes several different multi-frequency signal notch filter structures. Although this scheme also uses the lattice IIR ANF structure, it has deviations and the convergence speed is average.

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