Performance of the Adaptive Noise Canceller with a Noisy Reference -Non-Wiener Solutions.

摘要

The performance of the adaptive noise canceller (ANC) is typically analyzed in terms of Wiener filter theory. However, a narrowband signal in the reference at a frequency for which there is no correlated signal in the primary gives rise to a notch in the output spectrum, a solution which lies outside the scope of the classical theory. In this report, an analytic expression for the output spectrum is derived for the more general case of a reference signal containing a sinusoid in white noise (assumed no reference noise). In general, although the notch depth diminishes with decreasing signal-to-noise ratio, the exact functional relationship depends on the primary input; i.e., there is no longer a time invariant relationship between the output and primary spectra. These results are shown to reduce to those of the classical Wiener filter in the appropriate context. (Author)