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Convention Paper

Another Approach to Time Delay Spectrometry

Authors: Vanderkooy, John

AES Convention 79 · Paper 2285 · October 1985

Abstract

This paper traces methods of measuring frequency response and shows that Time Delay Spectrometry is a natural extension of such methods. A mathematical analysis shows how TDS measures the complex transfer function of a system, and calculated examples illustrate the effect of sweep rate and filter bandwidth. The demodulated chirp is usually stored in the memory of an associated display computer or analyzer, and post-processing of this data is feasible. If an undelayed demodulation chirp is used together with a fairly wideband output filter, then the output will represent the signals from a range of time delays. A software delay and output filter implementation is discussed which has a number of advantages, including multiple processing of data that needs to be captured only once, and application of digital output filters that show no spectral bias. An example of this technique is shown in unraveling the frequency responses of two loudspeakers whose simultaneously excited signals have very little difference in arrival time.

Details

Published in
AES Convention 79
AES Convention
79
Paper number
2285
Publication date
October 6, 1985
Session subject
Transducers
Affiliation
University of Waterloo, Waterloo, Ontario, Canada (See document for exact affiliation information.)
Type
Convention Paper