[num,den] = tf(sysobj)
converts the discrete-time filter System
object™ to numerator and denominator coefficient vectors of the equivalent transfer
function.
[num,den] = tf(sysobj,'Arithmetic',arithType)
analyzes the filter System
object based on the arithmetic specified in arithType.
Compute the transfer function of a biquad filter using the tf function.
Create a fourth-order, lowpass biquadratic filter object with a normalized cutoff frequency of 0.4.
[z,p,k] = ellip(4,1,60,0.4); % Set up the filter
[s,g] = zp2sos(z,p,k);
biquad = dsp.BiquadFilter(s,g,'Structure','Direct form I')
biquad =
dsp.BiquadFilter with properties:
Structure: 'Direct form I'
SOSMatrixSource: 'Property'
SOSMatrix: [2x6 double]
ScaleValues: 0.0351
NumeratorInitialConditions: 0
DenominatorInitialConditions: 0
OptimizeUnityScaleValues: true
Show all properties
Compute the transfer function of the designed biquadratic filter. The tf function returns the numerator and the denominator coefficient vectors of the filter.
arithType — Arithmetic type 'double' (default) | 'single' | 'Fixed'
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
filter. The 'Arithmetic' property set to 'Fixed'
applies only to filter System objects with fixed-point properties.
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