function [freq,real,imag]=HPr(filename);
%
% Read in HP spectrum analyzer files for transfer functions saved using HP 3536A
% and converted using 63x_mx.bat batch file from the /lifutil folder on Bob's Desktop
%
% freq = array of frequencies that data were measured at
% real = real part of frequency response
% imag = imaginary part of frequency response
%
% (Modified by Dave Bonfield from HPread.m, supplied by AJW.)
%
fid = fopen(filename,'r');
%
% three header lines, which contain the # of data points:
t1 = fgetl(fid);
t2 = fgetl(fid);
t3 = fgetl(fid);
[q1 N q3 q4] = strread(t3,'%s%d%d%s');
%
% now the frequency data; read until the next comment line:
freq = fscanf(fid,'%f');

% now a comment line, also containing the # of data points:
t4 = fgetl(fid);
[q1 N q3 q4] = strread(t4,'%s%d%d%s');
%
% now the real part of the frequency response:
real = fscanf(fid,'%f', N);
%
% now the imaginary part of frequency response
imag = fscanf(fid,'%f', N);
%
% close the file:
fclose(fid);
% return;