TSM and S+N+T
Time Scale Modification (TSM), and/or frequency scaling, are
relatively easy to implement in a sines+noise+transient (S+N+T) model
(§10.4.4). Figure 10.17 illustrates schematically
how it works. For TSM, the envelopes of the sinusoidal and noise
models are simply stretched or squeezed versus time as desired, while
the time-intervals containing transients are only translated
forward or backward in time--not time-scaled. As a result,
transients are not ``smeared out'' when time-expanding, or otherwise
distorted by TSM. If a ``transientness'' measure
is defined,
it can be used to control how ``rubbery'' a given time-segment is;
that is, for
, the interval is rigid and can only translate
in time, while for
it is allowed stretch and squeeze along
with the adjacent S+N model. In between 0 and 1, the time-interval
scales less than the S+N model. See [149] for more details
regarding TSM in an S+N+T framework.
Next Section:
TSM by Resampling STFTs Across Time
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S+N+T Sound Examples