Toni: moved Programmer Guide/SPU Reference/FFANA to Programmer Guide/SPU Reference/FFANA FFSYN

2011-04-28T10:00:10Z

moved Programmer Guide/SPU Reference/FFANA to Programmer Guide/SPU Reference/FFANA FFSYN

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Toni: moved Programmer Guide/SPU Reference/FFANA or FFSYN - filter I or O modules - simple Wiener filter implementation to Programmer Guide/SPU Reference/FFANA

2011-04-28T09:59:24Z

moved Programmer Guide/SPU Reference/FFANA or FFSYN - filter I or O modules - simple Wiener filter implementation to Programmer Guide/SPU Reference/FFANA

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Christian: Text replace - "S_TOOLS-STx" to "{{STX}}"

2011-04-05T15:58:17Z

Text replace - "S_TOOLS-STx" to "{{STX}}"

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	Functional diagram of <code>FFANA</code> and <code>FFSYN</code> SPAtoms in the framework of the ~~S_TOOLS-STx~~ analysis/synthesis model.		Functional diagram of <code>FFANA</code> and <code>FFSYN</code> SPAtoms in the framework of the {{STX}} analysis/synthesis model.

Admin: 1 revision: Initial import

2010-11-18T16:31:53Z

1 revision: Initial import

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193.171.195.8: initial import

2010-05-17T13:05:27Z

initial import

New page

{{DISPLAYTITLE:{{SUBPAGENAME}}}}
====FFANA / FFSYN - filter I/O modules - simple Wiener filter implementation====

Analyse a signal using a simple Wiener filter.

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

<code>FFANA <var>WIN L TYPE FMT</var></code>

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

;<var>WIN</var>

:The name of a shell wave item for signal input (mono).

;<var>L</var>

:The filter/frame length in samples.

;<var>TYPE</var>

:The analysis/resynthesis filter type. The following values are supported:

:<code>NOOVERLAP</code>|<code>0</code> - a frame with 2.n samples is used for analysis, where the first half is filled with a signal frame and the 2nd half is set to 0. This method minimizes the effects (distortions) of the cyclic convolution. The input frames are not overlapped. The length of A and B is 2.(n/2+1).

:<code>HALFOVERLAP</code>|<code>1</code> - the input signal is multiplied with a Hanning window and half overlapped. The length of A and B is n/2+1.

;<var>FMT</var>

:The format of the output spectrum The following values are supported:

:<code>COMPLEX</code>|<code>0</code> - A is the real part and B the imaginary part of the complex spectrum.

:<code>MAGNITUDE</code>|<code>1</code> - A is the magnitude spectrum and B the phase spectrum.

:<code>POWER</code>|<code>2</code> - A is the power spectrum and B the phase spectrum.

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

;<var>A</var>

:First part of the signal spectrum (dependant on <var>FMT</var>).

;<var>B</var>

:Second part of the signal spectrum (dependant on <var>FMT</var>).

;<var>SR</var>

:The sampling rate.

Synthesise a signal using a simple Wiener filter.

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

<code>FFSYN <var>WOUT L TYPE FMT A B</var></code>

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

;<var>WOUT</var>

:The name of a shell wave item for the signal output (compatible to WIN).

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

none

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

The two atoms <code>FFANA</code> and <code>FFSYN</code> implement the analysis and re-synthesis modules for signal processing methods using the fast-convolution technique. The <code>FFANA</code> atom partitions the signal into frames and performs the Fourier transform. The synthesis module <code>FFSYN</code> uses the inverse Fourier transform and an overlap-add method to reconstruct the signal stream.

The FFT length n is set via the input <var>L</var>. If <var>L</var> is not a power of 2, the FFT length is set to the next power of 2 greater than or equal to <var>L</var>. The spectrum of the current frame is stored in the outputs <var>A</var> and <var>B</var>.

The source and target wave items must be mono signals with equal sampling rates and lengths. At the end of the process, the analyser atom appends zero-frames to the signal, while the synthesis-atom empties the delay buffers.

In the following example of a filter SPU, the magnitude spectrum is processed by the modification module and the phase spectrum is left untouched. For the filter/modification section any kind of stationary or adaptive process can be used.

[[File:1230.png]]

Functional diagram of <code>FFANA</code> and <code>FFSYN</code> SPAtoms in the framework of the S_TOOLS-STx analysis/synthesis model.

Programmer Guide/SPU Reference/FFANA FFSYN - Revision history

Toni: moved Programmer Guide/SPU Reference/FFANA to Programmer Guide/SPU Reference/FFANA FFSYN

Toni: moved Programmer Guide/SPU Reference/FFANA or FFSYN - filter I or O modules - simple Wiener filter implementation to Programmer Guide/SPU Reference/FFANA

Christian: Text replace - "S_TOOLS-STx" to "{{STX}}"

Admin: 1 revision: Initial import

193.171.195.8: initial import