Audio weighting filter specification object
HAwf
= fdesign.audioweighting
HAwf
= fdesign.audioweighting(spec
)
HAwf
= fdesign.audioweighting(spec
,specvalue1
,specvalue2
)
HAwf
= fdesign.audioweighting(specvalue1
,specvalue2
)
HAwf
= fdesign.audioweighting(...,Fs)
Supported audio weighting filter types are: A weighting, C weighting, C-message, ITU-T 0.41, and ITU-R 468–4 weighting.
constructs
an audio weighting filter specification object HAwf
= fdesign.audioweightingHAwf
with
a weighting type of A and a filter class of 1. Use the design
method and set the 'SystemObject'
flag
to true
, to instantiate a System object™ based
on the specifications in HAwf
. Use designmethods
to find valid filter design
methods. Because the standards for audio weighting filters are in
Hz, normalized frequency specifications are not supported for fdesign.audioweighting
objects.
The default sampling frequency for A weighting, C weighting, C-message,
and ITU-T 0.41 filters is 48 kHz. The default sampling frequency for
the ITU-R 468–4 filter is 80 kHz. If you invoke the normalizefreq
method, a warning is issued
when you instantiate the System object and the default sampling
frequencies in Hz are used.
returns an audio weighting filter specification object using default values for the
specification in HAwf
= fdesign.audioweighting(spec
)spec
. The following are valid entries for
spec
. The entries are not case sensitive.
'WT,Class'
(default
spec
)
The 'WT,Class'
specification is valid for A weighting
and C weighting filters of class 1 or 2.
The weighting type is specified by the character vector:
'A'
or 'C'
. The class is the
scalar 1 or 2.
The default values for 'WT,Class'
are
'A',1
.
'WT'
The 'WT'
specification is valid for C-message
(default), ITU-T 0.41, and ITU-R 468–4 weighting filters.
The weighting type is specified by the character vector:
'Cmessage'
, 'ITUT041'
, or
'ITUR4684'
.
constructs
an audio weighting filter specification object HAwf
= fdesign.audioweighting(spec
,specvalue1
,specvalue2
)HAwf
and
sets its specifications at construction time.
constructs
an audio weighting filter specification object HAwf
= fdesign.audioweighting(specvalue1
,specvalue2
)HAwf
with
the specification 'WT,Class'
using the values you
provide. The valid weighting types are 'A'
or 'C'
.
specifies
the sampling frequency in Hz. The sampling frequency is a scalar trailing
all other input arguments. HAwf
= fdesign.audioweighting(...,Fs)
|
Weighting type The weighting type defines the frequency response of the filter. The valid weighting types are: A weighting, C weighting, C-message, ITU-T 0.41, and ITU-R 468–4 weighting. The weighting types are described in More About. |
|
Filter Class Filter class is only applicable for A weighting and C weighting
filters. The filter class describes the frequency-dependent tolerances
specified in the relevant standards [1], [2]. There are two possible class values:
1 and 2. Class 1 weighting filters have stricter tolerances than class
2 filters. The filter class value does not affect the design. The
class value is only used to provide a specification mask in Default: |
[1] American National Standard Design Response of Weighting Networks for Acoustical Measurements, ANSI S1.42-2001, Acoustical Society of America, New York, NY, 2001.
[2] Electroacoustics Sound Level Meters Part 1: Specifications, IEC 61672-1, First Edition 2002-05.
[3] Fletcher, H. and W.A. Munson. “Loudness, its definition, measurement and calculation.” Journal of the Acoustical Society of America, Vol. 5, 1933, pp. 82–108.
[4] Measurement of Audio-Frequency Noise Voltage Level in Sound Broadcasting, International Telecommunication Union Recommendation ITU-R BS.468-4, 1986.
[5] Psophometer for Use on Telephone-Type Circuits, ITU-T Recommendation 0.41.
[6] Transmission Parameters Affecting Voiceband Data Transmission-Measuring Techniques, Bell System Technical Reference, PUB 41009, 1972.