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THE AMBIGUITY DIAGRAM |
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function ambiguity(pts, wfm, parm3) % Plots ambiguity diagram, frequency content, zero doppler cut, and % zero range cut % Function called with zero inputs
if nargin < 1 pts = 2000; end % Function called with zero or one inputs if nargin < 2 wfm = 2; end % Function called with zero, one or two inputs if nargin < 3 if wfm == 2 slope = 0.01; % Slope must be <= 0.5, 0.01 = narrowband chirp, 0.1 = wideband chirp
else slope = 0; end cycles = 10; % Any number of inputs
else if wfm == 2 slope = parm3; else slope = 0; end cycles = parm3; end % Call the function corresponding to the given waveform if wfm == 1 [reference, convolution] = waveform1(pts); elseif wfm == 2 [reference, convolution] = waveform2(pts,slope); elseif wfm == 3 [reference, convolution] = waveform3(pts,cycles); end % Convert the result to decibels scale = reference' * reference; convolution = 10 * log10(convolution / scale); % Plot everything % Frequency content of waveform reference = [reference; 0 * [1:(3 * pts)]']; reference = reference .* exp(0.25i * pi * [1:(4 * pts)]'); reffreq = fft(reference / scale); subplot(2, 2, 3); plot([1:(2*pts)], (10 * log10(abs(reffreq(1:(2 * pts), 1))))) title('Reference Waveform Frequency Content', 'FontWeight', 'bold'); axis([1, (2 * pts), -50, 0]); disp('convolution size = ') size(convolution) % Zero Doppler Cut t = 1:pts; x = 1:((2 * pts) - 1); subplot(2, 2, 2); plot(x, convolution(:, 501)) title('Zero Doppler Cut', 'FontWeight', 'bold'); axis([1, ((2 * pts) -1), -50, 0]); % Zero Range Cut frange = -5:0.01:5; subplot(2, 2, 4); plot(frange, convolution(pts, :)) title('Zero Range Cut', 'FontWeight', 'bold'); axis([-5, 5, -50, 0]); % Ambiguity Diagram subplot(2, 2, 1); 'SHADING FLAT'; colormap('jet'); surf(frange', x', convolution, 'EdgeColor', 'none'); title('Ambiguity Diagram', 'FontWeight', 'bold'); axis([-5, 5, 0, (2 * pts), -40, 0]); ^ back to top ^ |
MOTIVATION – Why this is important OBJECTIVE – What we hoped to achieve AMBIGUITY DIAGRAM - What it is AMBIGUITY DIAGRAM - How to read it WAVEFORMS – The signals we analyzed RESULTS – Results for CW and PCM CHIRP - A closer look POSSIBLE EXTENTIONS – What’s next CODE - Fascinating stuff ACKNOWLEDGMENTS - Who we have to thank |