How can I plot S-parameter of differential signal SDD21 on Matlab?

How can I plot SDD21 (s-paraemters) from an .s4P file in matlab?

Answer 1

[Raghunathraju]

Hi Aastha,

As per my understanding, you want to plot differential s-parameters from .s4P file in MATLAB.

You can use the function ‘s2sdd’ to convert s-parameters into differential mode.

Example:

S = sparameters('Random.s4p');
s4p = S.Parameters; 
s_dd = s2sdd(s4p);

Let say your differential mode s-parameters are stored in a variable “s_dd”.

If 's_dd 'is a 2x2x1496 complex double, to plot the sdd21 you should convert it to double.

To do so you can do the following:

SDD_Parameters=(abs(reshape(s_dd,4,1496,1)))';

To know more about ‘reshape’ function click on reshape.

SDD_Parameters is a 1496x4 double. Third column in SDD_Parameters represent SDD21.

SDD_21= 20*log10(SDD_Parameters(:,3));  % Magnitude in dB

To get frequency range

Freq=S.Frequencies;

Which would be 1496x1 double.

Now you can use plot function to plot SDD21 vs Freq.

plot(Freq, SDD_21);

For more information go through the following MATLAB Documentation:

s2sdd