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The use of a frequency-selective method for time delay estimation between two channel data was described. The proposed algorithm, based on a stochastic gradient technique, exhibits a low numerical complexity and provides an alternative to data prefiltering and time delay estimation when the source and noise signals have different spectral properties. Time delay estimation was achieved through parameterization of the impulse response in the delay. Experimental results showed that the time delay estimate can be easily performed with an appropriate choice of prefilter.

A novel procedure based on a deconvolution approach with an additive regularization term was proposed for multipath time-delay detection and estimation. The objective is to estimate the number of paths and the associated attenuation and delay for each path. The approach allows the transformation of the underlying optimization problem into a quadratic program that makes it easily and quickly solved by standard programs. The procedure proved capable of handling more severe cases than other methods.

In this paper, a new comb filter design method using fractional sample delay is presented. First, the specification of the comb filter design is transformed into that of fractional delay filter design. Then, conventional finite impulse response (FIR) and allpass filter design techniques are directly applied to design fractional delay filter with transformed specification. Next, we develop a constrained fractional delay filter design approach to improve the performance of the direct design method. Finally, several design examples and an experiment of the power line interference removal in electrocadiogram (ECG) signal are demonstrated to illustrate the effectiveness of this new design approach. Index Terms - Comb filter, fractional delay filter, harmonic interference removal.

The definition of the Teager energy operator over complex-valued signals was determined with respect to the ambiguity function. The relationship between the Teager energy operator and the ambiguity function allows the use of the Teager energy in estimating the second moment angular bandwidth and the moments of a signal duration as well as that of its spectrum. Furthermore, the relation of the second moment angular bandwidth to the time delay estimation was derived.