Interfrence Cancellation with Interpolated FFT

Hiroomi HIKAWA  Vijay K. JAIN  

IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences   Vol.E79-A   No.3   pp.395-401
Publication Date: 1996/03/25
Online ISSN: 
Print ISSN: 0916-8508
Type of Manuscript: PAPER
Category: Digital Signal Processing
FFT,  digital filter,  spectrum estimation,  interference cancellation,  

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We present a new method to cancel interfering sinusoidal signals. In this method, the Interpolated FFT (IpFFT) algorithm is used to estimate the parameters of the interference signal: frequency, amplitude and phase. The cancellation is then performed in the time domain. In order for the IpFFT to perform reliably, accurate spectral information about the interference signal is needed. Since, the information signal masks the interference signal, it becomes difficult to estimate the parameters of the interference signal. To alleviate this masking effect, two techniques are discussed here. These techniques involve frame update of interference spectral information of the interference signal, and adaptive averaging. Significant improvement over conventional frequency domain filterings is achieved. The price paid is only little, beyond the computation of the FFT. Comparison with the conventional frequency domain filter shows that our system has approximately 5dB better cancellation capability for a single interfering signal.