%SPECBIN		Creates a spectrogram of a binary file

%Shane Crockett - 09JUN98
%For plotting spectragram of tatr data

global f t B																		%Makes these variables available to all m.files

filename = input('Binary filename to analyize? ','s');					% Asks user for name of signal to be analysized

fid = fopen(filename);																% Opens the specified signal 

% Reads the signal into g

g = fread(fid, 'float');													
   
% Calculates the spectrogram for the signal using 128 DFTs
% Sample rate is approximately 50 Msamples per sec
% Window sampling using a 128-point half cosine waveform (Hanning Window)
% The window is shifted by 8 points (1/16th of the window) to allow for overlapping

[X, f, t] = specgram(g,128,50*10^6,hanning(128),120);                                                                

% Consider signal in terms of power
B = X.*conj(X);

% Scales Y Axis properly
f = f + 25500000;

% Plots the spectrogram as an image

r = imagesc(t, f, log(B));						

% Scales the data for mapping
%Image plots from the top down, so it must be told to plot from the bottom up

titl = ['Spectrogram of ' filename];
title(titl)

xlabel('Time (sec)')
ylabel('Frequency (MHz)')
set(r, 'CDataMapping', 'scaled')												
set(gca, 'YDir', 'normal', 'YTicklabel', [30 35 40 45 50 55])%, 'XTickMode', 'manual', 'XTickLabel', [0 50 100 150 200 250 300 350 400])    
set(gcf, 'Position', [50 25 400 350])

% Administrative to reduce memory 
clear X r fid

%Defines the colormap and provides a colorbar
load my5
colormap(my5);
colorbar