I have the measurements of a filter’s Group delay and S-parameters. The S-parameters are of the following form, presented in a touchstone file.
!Agilent Technologies,N5242A,MY49421489,A.09.33.09
!Agilent N5242A: A.09.33.09
Date: Thursday, March 22, 2012 19:50:06
!Correction: S11(Full 2 Port(1,2))
!S21(Full 2 Port(1,2))
!S12(Full 2 Port(1,2))
!S22(Full 2 Port(1,2))
!S2P File: Measurements: S11, S21, S12, S22: Hz S dB R 50
1450000000 -0.44925556 132.79056 -43.664959 42.970737 -43.609634 45.291161 -0.41757283 131.60133
The filter’s Group delay data are like those demonstrated below:
!CSV A.01.01 !Date: Thursday March 22
!Source: Standard
BEGIN CH1_DATA
Freq(Hz) S21 Delay(s)
1.45E+09 -2.02E-08
1.45E+09 -1.32E-08
1.45E+09 -1.77E-08
1.45E+09 -1.70E-08
1.45E+09 -1.56E-08
1.45E+09 -1.36E-08
1.45E+09 -1.20E-08
What I want to do is simulate the impact that the group delay will have on a particular waveform using MATLAB. I tried to use the fdesign.arbgrpdelay in order to insert my group delay data and somehow observe how that would impact on a waveform but I am getting the following errors:
Error using fdesign.abstracttype/superdesign (line 96) Design options must be specified as a structure or as parameter-value pairs.
Error in fdesign.abstracttype/design (line 11)
varargout{1} = superdesign(this, varargin{:});
Error in allpassfilterarbitrarygrpdly (line 413)
Hgd = design(hgd,'iirlpnorm','Weights','MaxPoleRadius',0.95);
I also tried to use fdatool but I couldn't find a way of designing a filter by changing its group delay. The group delay was flat in all the available designs.
Does anyone knows how I can use the Group delay measurements in matlab to simulate a filter through its group delay?