Toni: moved Programmer Guide/SPU Reference/SHEPARD - A Shepard tone generator to Programmer Guide/SPU Reference/SHEPARD

2011-04-28T10:08:48Z

moved Programmer Guide/SPU Reference/SHEPARD - A Shepard tone generator to Programmer Guide/SPU Reference/SHEPARD

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2010-11-18T16:31:55Z

1 revision: Initial import

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2010-05-17T13:05:27Z

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====SHEPARD - A Shepard tone generator====

=====Usage:=====

<code>SHEPARD <var>SR</var> <var>L</var> <var>F1</var> <var>F2</var> <var>A</var> <var>T</var> <var>Q</var></code>

=====Inputs:=====

;<var>SR</var>

:The sampling rate in Hz

;<var>L</var>

:The length of the output buffer (number of samples / evaluation cycle).

;<var>F1</var>

:The start frequency in Hz.

;<var>F2</var>

:The end frequency in Hz.

;<var>A</var>

:The maximum component magnitude (linear).

;<var>T</var>

:The frequency change rate (seconds / interval step).

;<var>Q</var>

:The interval stepping factor.

=====Outputs:=====

;<var>Y</var>

:A number (<var>L</var>=1) or vector (<var>L</var>>1) samples of synthesized Shepard tone.

=====Function:=====

The <code>SHEPARD</code> atom implements a method for synthesizing rising and falling Shepard tones. The factor <var>Q</var> defines the interval ratio between two components (def.=2) and the value of <var>T</var> is the duration used for one interval step (in seconds, def.=1). If <var>F1</var> is lower than <var>F2</var>, a tone with raising frequencies is generated, otherwise the frequencies are falling. The number of components <code>n</code> is computed to satisfy the conditions for <code>fn</code>. In one time interval <var>T</var>, the frequency of a component <code>i</code> is changed continuously from <code>fi</code> to <code>fi</code>.<var>Q</var> (rising) or <code>fi</code>/<var>Q</var> (falling). After each interval one component leaves the frequency range (and is removed) while a component with starting frequency <var>F1</var> is added to the tone.

[[File:1275.png]]

with:

fmin = min(<var>F1</var>,<var>F2</var>),
fmax = max(<var>F1</var>, <var>F2</var>)

Programmer Guide/SPU Reference/SHEPARD - Revision history

Toni: moved Programmer Guide/SPU Reference/SHEPARD - A Shepard tone generator to Programmer Guide/SPU Reference/SHEPARD

Admin: 1 revision: Initial import

193.171.195.8: initial import