Accurate Low-Frequency Magnitude and Phase Estimation in the Presence of DC and Near-DC Aliasing
Efficient high resolution parameter estimation of sinusoidal elements has been shown to be of fundamental importance in applications such as measurement, parametric decomposition of sounds and low bitrate audio coding. It has been shown that certain methods such as the Complex Spectral Phase Evolution (CSPE) can be used to estimate the true frequency, magnitude and phase of underlying tones in a signal with accuracy that is significantly more precise than the signal resolution of a transform based analysis. These methods usually require the signal elements to be spectrally separated so that the mutual interference is minimal. This paper extends the methods introduced in CSPE for low frequency real tone signals, where the interference or “leakage” from the negative frequencies is unavoidable, regardless of what analysis window is used. The new techniques give improved magnitude and phase estimates for the signal parameters.
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