Read Qucs .dat file with Matlab

[MJH1994]

Hi,
does anyone know the data structure of the .dat file of a S-parameter optimazation? I would like to extract the optimized capacitor values with Matlab. This works with the conversion to a .txt file for a simple circuit simulation but not for the more complex S-parameter simulation.

I am happy with any advice.

Best regards

MJH

[pault]

A couple of tweaks from the octave version of the load data set program seems to work for matlab with the .opt variables included when trying the stub_filter.sch example:

function [dataset] = loadQucsDataset(filename)

pos = 0;
dataset = [];

fid = fopen(filename, “rb”);
if fid < 0
error(“Cannot open data file.”)
return
end

if strcmp(fscanf(fid, “%8c”, 1), “QucsData”) == 0
error(“File is not a Qucs data file.”)
fclose(fid);
return
end

version = fread(fid, 1, “int32”, 0, “ieee-le”);
size = fread(fid, 1, “int32”, 0, “ieee-le”);

% load header containing a list of all variables in the file
header = fread(fid, size, “uchar”);

type = 0;
count = 0;
index = 0;
% search for the variable
while index+9 <= size
type = header(index+1) + 256*(header(index+2) + 256*(header(index+3) + 256*header(index+4)));
count = header(index+5) + 256*(header(index+6) + 256*(header(index+7) + 256*header(index+8)));

name = ”;
dependency = ”;
index = index + 9;
while header(index) > 0
name = strcat(name, char(header(index)));
index = index + 1;
end
if bitget(type, 2) == 1 % is dependent variable?
index = index + 1;
while header(index) > 0
dependency = strcat(dependency,char(header(index)));
index = index + 1;
end
end

if bitget(type, 3) == 0 % complex-valued numbers?
data = fread(fid, 2*count, “double”, 0, “ieee-le”);
data = data(1:2:2*count-1) + j*data(2:2:2*count);
else
data = fread(fid, count, “double”, 0, “ieee-le”);
end

pos = pos + 1;
dataset(pos).name = name;
dataset(pos).depName = dependency;
dataset(pos).size = count;
dataset(pos).type = type;
dataset(pos).data = data;
end

fclose(fid);
endfunction

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