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Doppler Simulation

It is well known that a time-varying delay line results in a frequency shift. Time-varying delay is often used, for example, to provide vibrato and chorus effects [17]. We therefore expect a time-varying delay-line to be capable of precise Doppler simulation. This section discusses simulating the Doppler effect using a variable delay line [470].6.6

Consider Doppler shift from a physical point of view. The air can be considered as analogous to a magnetic tape which moves from source to listener at speed $ c$ (see Fig.5.4). The source is analogous to the write-head of a tape recorder, and the listener corresponds to the read-head. When the source and listener are fixed, the listener receives what the source records. When either moves, a Doppler shift is observed by the listener, according to Eq.$ \,$ (5.2).6.7

Figure 5.4: Magnetic tape analogy.
\includegraphics{eps/tape}



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``Physical Audio Signal Processing'', by Julius O. Smith III, W3K Publishing, 2010, ISBN 978-0-9745607-2-4.
Copyright © 2014-03-23 by Julius O. Smith III
Center for Computer Research in Music and Acoustics (CCRMA),   Stanford University
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