Estimating Echo Times.

This paper establishes a procedure for estimating the various spectral parameters in an echo type situation where both the signal is received as well as lagged and attenuated forms of the signal. The lag parameters are assumed frequency dependent and the basic assumption made is that these lags are sufficiently large to cause significant variation in the spectrum over the narrow trend of frequencies considered. The asymptotic properties of the estimates of these parameters are established and some simulations and an analysis of real data are considered. [ABSTRACT FROM AUTHOR]