CW-Robot Octave Simulation - Revision history

Zach.swena: /* Morse.m */

2011-12-09T01:49:04Z

Morse.m

← Older revision		Revision as of 18:49, 8 December 2011
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	Dit = sin(2pif_code*t);		Dit = sin(2pif_code*t);
	ssp = zeros(size(Dit));		ssp = zeros(size(Dit));
	Dah = [Dit;Dit;Dit];		#Dah fixed by Zach Swena
	lsp = zeros(size([Dit;Dit;Dit]));		t2=0:1/Fs:3*1.2/code_speed; # one Dah of time is 3 times dit time
			t2=t2';
			Dah = sin(2pif_code*t2);
			lsp = zeros(size(Dah)); # changed size argument to function of Dah
			#Dah = [Dit;Dit;Dit];
			#lsp = zeros(size([Dit;Dit;Dit]));
	% Defining Characters & Numbers		% Defining Characters & Numbers
	A = [Dit;ssp;Dah];		A = [Dit;ssp;Dah];

2011-12-01T20:00:54Z

Find the maxima of a function

← Older revision		Revision as of 13:00, 1 December 2011
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	function [peak_indices] = maxima(a)		function [peak_indices] = maxima(a)
	% Finds the local maxima of a vector (1xn) and returns the indices		% Finds the local maxima of a vector (1xn) and returns the indices

	n=length(a);		n=length(a);
	r = [a(1,2:n) - a(1,1:n-1) <= 0, 1]; % derivative on the right <= 0		r = [a(1,2:n) - a(1,1:n-1) <= 0, 1]; % derivative on the right <= 0

2011-12-01T20:00:35Z

Find the maxima of a function

← Older revision		Revision as of 13:00, 1 December 2011
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	function [peak_indices] = maxima(a)		function [peak_indices] = maxima(a)
	% Finds the local maxima of a vector (1xn) and returns the indices		% Finds the local maxima of a vector (1xn) and returns the indices

	n=length(a);		n=length(a);
	r = [a(1,2n) - a(1,1n-1) <= 0, 1]; % derivative on the right <= 0		r = [a(1,2:n) - a(1,1:n-1) <= 0, 1]; % derivative on the right <= 0
	l = [1, a(1,2n) - a(1,1n-1) >= 0]; % derivative on the left >= 0		l = [1, a(1,2:n) - a(1,1:n-1) >= 0]; % derivative on the left >= 0
	d = l & r;		d = l & r;
	peak_indices = find(d);		peak_indices = find(d);

2011-12-01T19:06:57Z

Find the maxima of a function

← Older revision		Revision as of 12:06, 1 December 2011
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	function [peak_indices] = maxima(a)		function [peak_indices] = maxima(a)
	% Finds the local maxima of a vector (1xn) and returns the indices		% Finds the local maxima of a vector (1xn) and returns the indices

	n=length(a);		n=length(a);
	r = [a(1,2n) - a(1,1n-1) <= 0, 1]; % derivative on the right <= 0		r = [a(1,2n) - a(1,1n-1) <= 0, 1]; % derivative on the right <= 0

2011-12-01T19:06:43Z

Finding the Peak Frequencies Automatically

← Older revision		Revision as of 12:06, 1 December 2011
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	figure(2)		figure(2)
	plot(t,x,t,filteredx)		plot(t,x,t,filteredx)

			===Find the maxima of a function===
			function [peak_indices] = maxima(a)
			% Finds the local maxima of a vector (1xn) and returns the indices

			n=length(a);
			r = [a(1,2n) - a(1,1n-1) <= 0, 1]; % derivative on the right <= 0
			l = [1, a(1,2n) - a(1,1n-1) >= 0]; % derivative on the left >= 0
			d = l & r;
			peak_indices = find(d);

2011-11-15T17:57:04Z

Finding the Peak Frequencies Automatically

← Older revision		Revision as of 10:57, 15 November 2011
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	% This script demonstrates how a CW filter helps.		% This script demonstrates how a CW filter helps.
	% It ~~is a start on making a demodulator to decode multiple CW signals~~.		% It demonstrates using find.
	filter_width = 100; % Hz		filter_width = 100; % Hz
	Fs=48000;		Fs=48000;

2011-11-15T17:55:50Z

Matched Filter Demonstration

@@ Line 198: / Line 198: @@
   % This script shows how a matched filter (dot product) works.
   Fs=48000;
   speed = 20;
   code_f = 440;
   dit_time = 1.2/speed;
   x_length = 2^19;
   x=morse(' How r u?','morsecode.wav', 4, code_f, Fs, speed, x_length);
   t=0:1/Fs:1.2/speed;
   burst = sin(2*pi*code_f*t);
   N = length(burst);
   for k=1:x_length-N
   xk = x(k:1:(k+N-1));
   x_filtered(k) = burst*xk;
   end
   t1 = 0:1/Fs:1/Fs*length(x_filtered)-1/Fs;
   t2 = 0:1/Fs:1/Fs*length(x)-1/Fs;
   ts = 0:dit_time:x_length/Fs-2*dit_time;
   figure(2)
   clf;
@@ Line 227: / Line 218: @@
   %figure(3)
   %plot(t2,x,'r-')

2011-11-15T17:53:45Z

Check the Noise Audibly

← Older revision		Revision as of 10:53, 15 November 2011
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	xfiltered = filter(b,a,x);		xfiltered = filter(b,a,x);
	soundsc(xfiltered,Fs);		soundsc(xfiltered,Fs);

			===Matched Filter Demonstration===

			% This script shows how a matched filter (dot product) works.
			Fs=48000;

			speed = 20;
			code_f = 440;
			dit_time = 1.2/speed;

			x_length = 2^19;

			x=morse(' How r u?','morsecode.wav', 4, code_f, Fs, speed, x_length);

			t=0:1/Fs:1.2/speed;
			burst = sin(2picode_f*t);

			N = length(burst);

			for k=1:x_length-N
			xk = x(k:1:(k+N-1));
			x_filtered(k) = burst*xk;
			end

			t1 = 0:1/Fs:1/Fs*length(x_filtered)-1/Fs;
			t2 = 0:1/Fs:1/Fs*length(x)-1/Fs;

			ts = 0:dit_time:x_length/Fs-2*dit_time;

			figure(2)
			clf;
			plot(t1,x_filtered,'b-',ts,x_filtered(1:N:end),'r',ts,400ones(1,length(ts)),'r-')
			%figure(3)
			%plot(t2,x,'r-')

2011-11-15T17:51:24Z

Morse.m

← Older revision		Revision as of 10:51, 15 November 2011
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	Here are some Octave (or MATLAB) scripts your professor put together for you to help on your project.		Here are some Octave (or MATLAB) scripts your professor put together for you to help on your project.

	==Morse.m==		===Morse.m===

	This function called morse.m will generate morse code with noise added in for specified text.		This function called morse.m will generate morse code with noise added in for specified text.

2011-11-15T17:51:03Z

Check the Noise Audibly

← Older revision		Revision as of 10:51, 15 November 2011
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	endfunction		endfunction

	==Check the Noise Audibly==		===Check the Noise Audibly===

			% This script allows you to use your ear to see how much noise you have.
			Fs=48000;
			Fnyq = Fs/2;
			speed = 20;
			code_f = 440;
			x_length = 2^19;
			x=morse(' How r u?','morsecode.wav', 4, code_f, Fs, speed, x_length);
			soundsc(x,Fs);
			[b,a] = cheby1(4,2,[290/(Fnyq),690/(Fnyq)]);
			figure(1);
			clf;
			freqz(b,a,Fs);
			xfiltered = filter(b,a,x);
			soundsc(xfiltered,Fs);