Scale secondorder sections of dsp.BiquadFilter
System object
scale(biquad)
biquadnew = scale(biquad)
scale(biquad,pnorm)
scale(biquad,pnorm,Name,Value)
scale(biquad,pnorm,opts)
scale(biquad,'Arithmetic',ARITH)
scale(
scales
the biquad
)dsp.BiquadFilter
System object™, biquad
,
using peak magnitude response scaling (Linfinity, 'Linf'
).
This scaling reduces the possibility of overflows when your filter biquad
operates
in fixedpoint arithmetic mode.
biquadnew = scale(
generates
a new filter System object, biquad
)biquadnew
, with
scaled secondorder sections. The original filter System object, biquad
,
is not changed.
scale(
specifies
the norm used to scale the filter. Pnorm can be either a discretetimedomain
norm or a frequencydomain norm. Valid timedomain norms are biquad
,pnorm
)'l1'
, 'l2'
,
and 'linf'
. Valid frequencydomain norms are 'L1'
, 'L2'
,
and 'Linf'
. Note that L2norm is equal to l2norm
(Parseval's theorem) but the same is not true for other norms.
The different norms can be ordered in terms of how stringent
they are as follows: 'l1' >= 'Linf' >= 'L2' = 'l2'
>= 'L1' >= 'linf'
.
Using the most stringent scaling, 'l1'
, the
filter is the least prone to overflow, but also has the worst signaltonoise
ratio. Linfscaling is the most commonly used scaling in practice.
scale(
specifies
optional scaling parameters via by one or more biquad
,pnorm
,Name,Value
)Name,Value
pair
arguments.
scale(
uses
an options object to specify the optional scaling parameters in lieu
of specifying parametervalue pairs. The biquad
,pnorm
,opts
)opts
object
can be created using the scaleopts
method: opts
= scaleopts(biquad)
.
scale(
assumes
that the filter arithmetic is equal to ARITH. ARITH can be set to
one of biquad
,'Arithmetic',ARITH)'double'
, 'single'
, or 'fixed'
.
The scale method assumes a double precision filter when the arithmetic
input is not specified and the filter System object is in an unlocked
state. If 'Arithmetic'
is 'double'
or 'single'
,
the default values are used for all scaling options that are not specified
as an input to the scale
method. If 'Arithmetic'
is 'fixed'
,
the values used for the scaling options are set according to the settings
in the filter System object, biquad
. However,
if a scaling option is specified that differs from the settings in biquad
,
this option is used for scaling purposes but does not change the setting
in biquad
. For example, if you do not specify the 'OverflowMode'
scaling
option, the scale
method assumes that the 'OverflowMode'
is
equal to the value in the OverflowAction
property
of the System object, biquad
. If you do specify
an 'OverflowMode'
scaling option, then the scale
method
uses this overflow mode value regardless of the value in the OverflowAction
property
of the System object.



Discretetimedomain norm or a frequencydomain norm. Valid timedomain norm values for Filter norms can be ordered in terms of how stringent they are,
as follows from most stringent to least: 

Scale options object. You can create the 
Specify optional commaseparated pairs of Name,Value
arguments.
Name
is the argument
name and Value
is the corresponding
value. Name
must appear
inside single quotes (' '
).
You can specify several name and value pair
arguments in any order as Name1,Value1,...,NameN,ValueN
.

Specify the arithmetic used during analysis. When you specify Details for FixedPoint Arithmetic When you do not specify the arithmetic, the function uses doubleprecision arithmetic if the filter System object is in an unlocked state. If the System object is locked, the function performs analysis based on the locked input data type. 

Maximum allowed value for numerator coefficients. Default: 2 

Maximum allowed scale values. The filter applies the Default: 

Specifies whether and how to constrain numerator coefficient values. Possible options:


Sets the way the filter handles arithmetic overflow situations
during scaling. If your device does not have guard bits available,
and you are using saturation arithmetic for filtering, use 

Specify whether to constrain the filter scale values, and how
to constrain them. Choosing 

Reorder filter sections prior to applying scaling. Possible options:

[1] Dehner, G.F. "Noise Optimized Digital Filter Design: Tutorial and Some New Aspects." Signal Processing. Vol. 83, Number 8, 2003, pp. 1565–1582.