Touchstone Format (Extracting Specific Frequency from S-Parameters]

[felicia_1]

I can extract the S-parameters from touchstone file. However, it displays by column. What can I do if I want to extract certain frequency only (for example 1 GHz) and it will display its S-parameters automatically in Matlab?

 

[volker@muehlhaus]

Is this a question regarding Matlab syntax for matrix operations, or Touchstone syntax?

 

[felicia_1]

I can extract the S-parameters from touchstone file. However, it displays by column. What can I do if I want to extract certain frequency only (for example 1 GHz) and it will display its S-parameters automatically in Matlab?

Matlab syntax. Do you have any experience in extract certain specific frequency to display S-parameters in Matlab? (the frequency to be inserted will be decided by user).

 

[biff44]

the touchsotone file is a matrix, where the column 1 is the frequency, usually in MHz.

You would take the desired frequency, scan down the first column, until you find one row that is just below your frequency of interest, and the next row is just above your frequency of interes. I would then linearly average each s parameter data column and come up with the closes approximate data point.

 

[felicia_1]

the touchsotone file is a matrix, where the column 1 is the frequency, usually in MHz.

You would take the desired frequency, scan down the first column, until you find one row that is just below your frequency of interest, and the next row is just above your frequency of interes. I would then linearly average each s parameter data column and come up with the closes approximate data point.

thank you for the respond. Could you please provide simple example on this? I don't really get it.

 

[volker@muehlhaus]

Matlab syntax. Do you have any experience in extract certain specific frequency to display S-parameters in Matlab? (the frequency to be inserted will be decided by user).

felicia, I assume that you refere to the S-parameter functions in the Matlab RF toolbox? Sorry, I have no experience with that.

I think biff refers to the matrix and manual parsing of the file with homebrew code. However, the data in the Touchstone files has an extra number (frequency) for each frequency, so the overall data in the file isn't always readable as a matrix.

Only for S1P and S2P files, all data per frequency is in one line, which is easy to parse. For more ports, there are usually line breaks somehwere (no standard on the position of the line break). This gives different number of entries per line, because some lines include frequencies and the continued lines don't. This makes it a bit more complicated to parse the file.

 

[biff44]

**broken link removed**

 

[felicia_1]

**broken link removed**

Thank you for the suggestion. Anyone has any idea on extracting specific frequency in touchstone file format?

 

[volker@muehlhaus]

If you want an answer, why don't you answer questions?
Do you want to read the file "manually" with your own code, or do you use a library with Touchstone reader code (e.g. Matlab RF toolbox)?

 

[felicia_1]

If you want an answer, why don't you answer questions?
Do you want to read the file "manually" with your own code, or do you use a library with Touchstone reader code (e.g. Matlab RF toolbox)?

Use library with touchstone reader code.