Toni: moved Programmer Guide/SPU Reference/WIGNER - pseudo wigner distribution to Programmer Guide/SPU Reference/WIGNER

2011-04-28T10:16:55Z

moved Programmer Guide/SPU Reference/WIGNER - pseudo wigner distribution to Programmer Guide/SPU Reference/WIGNER

← Older revision	Revision as of 12:16, 28 April 2011
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Admin: 1 revision: Initial import

2010-11-18T16:31:55Z

1 revision: Initial import

← Older revision	Revision as of 18:31, 18 November 2010
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193.171.195.8: initial import

2010-05-17T13:05:27Z

initial import

New page

{{DISPLAYTITLE:{{SUBPAGENAME}}}}
====WIGNER - pseudo wigner distribution====

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

<code>WIGNER <var>X</var> <var>NSMT</var> <var>NFIR</var> <var>NFFT</var></code>

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

{|
|-
|X
|input signal, no default (must contain an odd number of samples)
|-
|NSMT
|smoothing length, default=7 (must be odd, automatic correction)
|-
|NFIR
|fir filter length, default=7 ( must be odd, automatic correction)
|-
|NFFT
|fft length, default=2M >= NX, (automatic correction)
|}

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

{|
|-
|<var>Y</var>
|smoothed pseudo Wigner distribution (SPWD) in dB
|}

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

This atom computes the smoothed pseudo Wigner distribution (SPWD) of the signal X. The time and frequency resolution depends on the parameters <var>NSMT</var> (smoothing length), <var>NFIR</var> (FIR filter length for the computation of the analytical signal) and <var>NFFT</var> (FFT length), and on the length of the input vector NX. The computed SPWD (in dB) consists of <var>NFFT</var> values and is stored in the output vector <var>Y</var>. This implementation of the SPWD is based on the algorithms published by W. Wokurek in his doctor thesis. The picture below shows the content of the frame buffer (input signal) <var>X</var>.

[[File:1311.png]]

Figure 7: Analysis frame of the Wigner distribution

with:

{|
|-
|NX
|length of input signal X, frame length
|-
|NFIR
|length of FIR filter for the computation of the analytical signal
|-
|NSMT
|length of time smoothing window
|-
|NWDW
|length of analysis window; the length of the analysis window is a basic parameter of the Wigner distribution. However, in this implementation it cannot be specified directly, rather it is derived from NX, NSMT and NFIR: NWDW = (NX<nowiki>-</nowiki>1)-(NSMT-1)-(NFIR-1)+1
|}

Programmer Guide/SPU Reference/WIGNER - Revision history

Toni: moved Programmer Guide/SPU Reference/WIGNER - pseudo wigner distribution to Programmer Guide/SPU Reference/WIGNER

Admin: 1 revision: Initial import

193.171.195.8: initial import