Programmer Guide/SPU Reference/RMSB - Revision history

193.171.195.47: /* Function: */

2015-04-16T10:53:15Z

Function:

← Older revision		Revision as of 12:53, 16 April 2015
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	To compute the energy in a frequency band the squared magnitudes inside the band are added. The input <var>REF</var> can be used to compute relative or absolute energy values.		To compute the energy in a frequency band the squared magnitudes inside the band are added. The input <var>REF</var> can be used to compute relative or absolute energy values.

	Table 21: Compute relative or absolute rms values{\|		Table 21: Compute relative or absolute rms values
			{\|
	\|-		\|-
	\|value of REF		\|value of REF
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	Before the computed energy values are stored in the output <var>Y</var>, they are converted according to the value of input <var>TYP</var>.		Before the computed energy values are stored in the output <var>Y</var>, they are converted according to the value of input <var>TYP</var>.

	Table 22: Type of output values{\|		Table 22: Type of output values
			{\|
	\|-		\|-
	\|value of TYP		\|value of TYP

193.171.195.47: /* Function: */

2015-04-16T10:52:26Z

Function:

← Older revision		Revision as of 12:52, 16 April 2015
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	This function computes the energy in different frequency bands of the spectrum X. The input <var>X</var> must be a magnitude spectrum (linear magnitudes) with an equally spaced frequency scale and a frequency range from 0 to <var>SR</var>/2 (e.g. an fft spectrum). The energy bands are defined by the inputs <var>DEF</var> and <var>P1</var>-<var>P3</var> in the following manner:		This function computes the energy in different frequency bands of the spectrum X. The input <var>X</var> must be a magnitude spectrum (linear magnitudes) with an equally spaced frequency scale and a frequency range from 0 to <var>SR</var>/2 (e.g. an fft spectrum). The energy bands are defined by the inputs <var>DEF</var> and <var>P1</var>-<var>P3</var> in the following manner:

	Table 20: Frequency band definitions selected by input <var>DEF</var>{\|		Table 20: Frequency band definitions selected by input <var>DEF</var>
			{\|
	\|-		\|-
	\|value of <var>DEF</var>		\|value of <var>DEF</var>

Toni: moved Programmer Guide/SPU Reference/RMSB - frequency band rms to Programmer Guide/SPU Reference/RMSB

2011-04-28T10:07:54Z

moved Programmer Guide/SPU Reference/RMSB - frequency band rms to Programmer Guide/SPU Reference/RMSB

← Older revision	Revision as of 12:07, 28 April 2011
(No difference)

Admin: 1 revision: Initial import

2010-11-18T16:31:54Z

1 revision: Initial import

← Older revision	Revision as of 18:31, 18 November 2010
(No difference)

193.171.195.8: initial import

2010-05-17T13:05:27Z

initial import

New page

{{DISPLAYTITLE:{{SUBPAGENAME}}}}
====RMSB - frequency band rms====

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

<code>RMSB <var>X SR DEF P1 P2 P3 REF TYP TABLE COL WIN DBREF</var></code>

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

{|
|-
|X
|amplitude spectrum vector (linear!!!)
|-
|SR
|sampling rate in Hz
|-
|DEF
|type of band/frequency definition {<code>Direct</code>, <code>Equal</code>, <code>Geometric</code>}
|-
|P1,P2,P3
|band definitions parameters (depends on DEF - see table below)
|-
|REF
|type of energy reference {<code>Full</code>|<code>Absolute</code>, <code>Band</code>|<code>Relative</code>}
|-
|TYP
|type of rms output values {<code>Power</code>, <code>LInear</code>, <code>LOgarithmic</code>}
|-
|TABLE
|name of parameter table
|-
|COL
|1st column for rms values in output table
|-
|WIN
|either a number (length of signal window) or a vector (length = length of signal window)
|-
|DBREF
|reference value for logarithmic output
|}

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

{|
|-
|<var>Y</var>
|band rms values
|}

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

This function computes the energy in different frequency bands of the spectrum X. The input <var>X</var> must be a magnitude spectrum (linear magnitudes) with an equally spaced frequency scale and a frequency range from 0 to <var>SR</var>/2 (e.g. an fft spectrum). The energy bands are defined by the inputs <var>DEF</var> and <var>P1</var>-<var>P3</var> in the following manner:

Table 20: Frequency band definitions selected by input <var>DEF</var>{|
|-
|value of <var>DEF</var>
|P1
|P2
|P3
|description
|-
|<code>0</code> or <code>DIRECT</code>
|fmin1 ...fminn
|fmax1 ...fmaxn
|<nowiki>-</nowiki>
|The energy in the frequency bands [fmin1,fmax1] .. [fminn,fmaxn] is computed. Overlapping bands are possible.
|-
|<code>1</code> or <code>EQUAL</code>
|fmin
|fmax
|n
|The frequency range [fmin,fmax] is split into n bands with equal bandwidth b=(fmax<nowiki>-</nowiki>fmin)/n. The boundaries of the n frequency bands are set to [fmin+i.b, fmin+(i+1).b] (with: i=0,..,n-1)
|-
|<code>2</code> or <code>GEOMETRIC</code>
|fmin
|fmax
|n
|The frequency range [fmin,fmax] is split into n bands with constant bandwidth ratio q=(fmax/fmin)1/n. The boundaries of the n frequency bands are set to [fmin.qi, fmin.q(i+1)] (with: i=0,..,n<nowiki>-</nowiki>1)
|}

To compute the energy in a frequency band the squared magnitudes inside the band are added. The input <var>REF</var> can be used to compute relative or absolute energy values.

Table 21: Compute relative or absolute rms values{|
|-
|value of REF
|energy computation
|-
|<code>0</code>, <code>1</code>, <code>FULL</code> or<code>ABSOLUTE</code>
|The energy ei is the sum of all aj2 with frequency fj is inside the band i.
|-
|<code>2</code>, <code>3</code>, <code>BAND</code> or<code>RELATIVE</code>
|The energy ei is computed as described above and than multiplied with k=2/SR.bi. This mode can be used to compute the energy density in a band.
|}

Before the computed energy values are stored in the output <var>Y</var>, they are converted according to the value of input <var>TYP</var>.

Table 22: Type of output values{|
|-
|value of TYP
|value stored in Y (and in the table columns)
|-
|<code>0</code> or <code>POWER</code>
|energy values ei as computed
|-
|<code>1</code> or <code>LINEAR</code>
|ei1/2
|-
|<code>2</code> or <code>LOGARITHMIC</code>
|10.log10(ei)
|}

If a table (defined by TABLE and <var>COL</var>) is specified, the values are also stored in the columns <var>COL</var> to <var>COL</var>+n-1 of the table. In each evaluation cycle the columns of one entry are filled (starting at entry 0).