AES E-Library

Another Approach to Time-Delay Spectrometry

Methods of measuring frequency response are traced, and it is shown that time-delay spectrometry (TDS) 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 postprocessing of these 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 need to be captured only once, and application of digital output filters that show no spectral bias. An example of the technique is shown in unraveling the frequency responses of two loudspeakers whose simultaneously excited signals have very little difference in arrival time.

Author: Vanderkooy, John
Affiliation: Audio Research Group, University of Waterloo, Waterloo, Ont. N2L 3Gl, Canada
JAES Volume 34 Issue 7/8 pp. 523-538; July 1986 Import into BibTeX

Click to purchase paper or login as an AES member. If your company or school subscribes to the E-Library then switch to the institutional version. If you are not an AES member and would like to subscribe to the E-Library then Join the AES!

This paper costs $20 for non-members, $5 for AES members and is free for E-Library subscribers.

Learn more about the AES E-Library

E-Library Location: (CD aes4)   /jrnl7888/1986/8116.pdf

Start a discussion about this paper!