[zphase,w]
= zerophase(sysobj) returns the zero-phase response vector,
zphase, and the corresponding frequency vector,
w, in radians/sample of the filter System object™ based on the current filter coefficients.
[zphase,w]
= zerophase(sysobj,n) returns the
n-point zero-phase response vector and the corresponding
n-point frequency vector in radians/sample of the filter System object.
[zphase,w]
= zerophase(___,Arithmetic=arithType) analyzes the
filter System object based on the arithmetic specified in arithType using
either of the previous syntaxes.
zerophase(sysobj) plots
the zero-phase response of the filter System object.
For more input options, see zerophase in Signal Processing Toolbox™.
n — Number of points over which zero-phase response is evaluated 8192 (default) | positive integer
Number of points over which the zero-phase response is evaluated around the upper
half of the unit circle. For an FIR filter where n is a power of
two, the computation is done faster using FFTs.
Data Types: double
arithType — Arithmetic type 'double' (default) | 'single' | 'Fixed'
Arithmetic used in the filter analysis, specified as 'double',
'single', or 'Fixed'. When the arithmetic
input is not specified and the filter System object is unlocked, the analysis tool assumes a double-precision filter. When the
arithmetic input is not specified and the System object is locked, the function performs the analysis based on the data type of
the locked input.
The 'Fixed' value applies to filter System objects with fixed-point
properties only.
When the 'Arithmetic' input argument is specified as
'Fixed' and the filter object has the data type of the
coefficients set to 'Same word length as input', the arithmetic
analysis depends on whether the System object is unlocked or locked.
unlocked –– The analysis object function cannot determine the coefficients
data type. The function assumes that the coefficients data type is signed,
has a 16-bit word length, and is auto scaled. The function performs
fixed-point analysis based on this assumption.
locked –– When the input data type is 'double' or
'single', the analysis object function cannot
determine the coefficients data type. The function assumes that the data
type of the coefficients is signed, has a 16-bit word length, and is auto
scaled. The function performs fixed-point analysis based on this
assumption.
To check if the System object is locked or unlocked, use the isLocked function.
When the arithmetic input is specified as 'Fixed' and the filter
object has the data type of the coefficients set to a custom numeric type, the object
function performs fixed-point analysis based on the custom numeric data type.
Zero-phase response vector, evaluated at n equally-spaced
points around the upper half of the unit circle, returned as a vector. If
n is not specified, the function uses a default value of
8192.
Data Types: double
w — Frequency vector vector
Frequency vector of length n in radians/sample.
w consists of n equally-spaced points around
the upper half of the unit circle (from 0 to π radians/sample). If
n is not specified, the function uses a default value of
8192.
The dsp.BiquadFilter object issues a warning and will be removed in a
future release. Use the dsp.SOSFilter object
instead. For more information on how to replace your existing code, see the
Compatibility Considerations section in the dsp.BiquadFilter reference page.
R2024b: Support for dsp.DCBlocker object
Starting in R2024b, this function supports the dsp.DCBlocker object.
R2024a: zerophase function no longer uses Filter Visualization
Tool
When you call the zerophase function with no output arguments, the
function no longer uses Filter Visualization Tool to plot the zero phase response of the
filter. Starting in R2024a, the function uses the MATLAB® plot instead.
You do not need to make any changes to your code.
R2023b: Support for dsp.ParallelFilter and dsp.Delay Objects
Starting in R2023b, the zerophase analysis function supports the
dsp.ParallelFilter
and the dsp.Delay objects.
R2023b: dsp.BiquadFilter object will be removed
The dsp.BiquadFilter object will be removed in a future release. Use
the dsp.SOSFilter object
instead.
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