Impulse response of discrete-time filter System object
[impResp,t] = impz(sysobj)
[impResp,t] = impz(sysobj,n)
[impResp,t] = impz(sysobj,n,fs)
[impResp,t] = impz(sysobj,,fs)
[impResp,t] = impz(sysobj,'Arithmetic',arithType)
fvtool to plot the impulse response of the filter
You can use
impz for both real and complex filters. When you
omit the output arguments,
impz plots only the real part of the
For more input options, refer to
Create a discrete-time filter for a fourth-order, lowpass elliptic filter with a cutoff frequency of 0.4 times the Nyquist frequency. Use a second-order sections structure to resist quantization errors. Plot the first 50 samples of the impulse response, along with the reference impulse response.
d = fdesign.lowpass(.4,.5,1,80);
Create a design object for the prototype filter. Use
ellip to design a minimum order discrete-time biquad filter.
biquad = design(d,'ellip','Systemobject',true);
Plot the impulse response.
impz(biquad); axis([1 75 -0.2 0.35])
sysobj— Input filter
Input filter, specified as as one of the following filter System objects:
n— Number of filter coefficients
Length of the impulse response vector, specified as a positive integer.
fs— Sampling frequency
1(default) | positive scalar
Sampling frequency used in computing the impulse response, specified as a positive scalar.
arithType— Arithmetic type
Specify the arithmetic used during analysis. When the arithmetic input is not specified and
the filter System object is unlocked, the analysis tool assumes a double-precision
'Arithmetic' property set to
applies only to filter System objects with fixed-point properties.
impResp— Impulse response
Impulse response, returned as an
n-element vector. If
n is not specified, the length of the impulse
response vector equals the number of coefficients in the filter.
t— Time vector
Time vector of length
n, in seconds.
t consists of
n equally spaced
points in the range
n is not specified, the function uses the number of
coefficients of the filter.