"Pert." . . . . . . "Quarterly Progress Report Number 4, 1 May - 31 July 1967"@en . . . . . . . . "It was pointed out in the previous progress report that the techniques for computing a Cepstrum have certain shortcomings in a mathematical sense. These restrictions were placed on the technique by certain approximations and assumptions that were made concerning the relative amplitudes of the original signal and echoes. This past quarter, effort was made to derive alternate techniques for computing Cepstrum, using as few mathematical assumptions as possible. (Author)."@en . . . . . . "Signal to noise ratio." . . "High pass filters." . . "Acoustic Detection and Detectors." . . "Numerical Mathematics." . . "Computer programs." . . "Sonar." . . "TEXAS UNIV AT AUSTIN DEFENSE RESEARCH LAB." . . "Echoes." . . "Computerized simulation." . . "Cepstrum technique." . . "Computer Programming and Software." . . "Mathematical models." . . "Recursive filters." . . . .