ti_mo
146 lines
4.4 KiB
Plaintext
146 lines
4.4 KiB
Plaintext
trace1 = load("traces/2412mhz.mat", "iq");
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trace2 = load("traces/2432mhz.mat", "iq");
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trace3 = load("traces/2452mhz.mat", "iq");
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trace4 = load("traces/2472mhz.mat", "iq");
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window = 512;
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overlap = 64;
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fft_precision = 2048;
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sample_rate = 20e6; % 20 MS/s -> 20e6 S/s
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% 1.
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duration1 = length(trace1.iq) / sample_rate;
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duration2 = length(trace2.iq) / sample_rate;
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duration3 = length(trace3.iq) / sample_rate;
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duration4 = length(trace4.iq) / sample_rate;
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% 2.
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% get all four plot values
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[S1,F1,T1] = spectrogram(trace1.iq, window, overlap, fft_precision, sample_rate, "centered");
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[S2,F2,T2] = spectrogram(trace2.iq, window, overlap, fft_precision, sample_rate, "centered");
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[S3,F3,T3] = spectrogram(trace3.iq, window, overlap, fft_precision, sample_rate, "centered");
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[S4,F4,T4] = spectrogram(trace4.iq, window, overlap, fft_precision, sample_rate, "centered");
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mag1 = abs(S1).^2;
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mag2 = abs(S2).^2;
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mag3 = abs(S3).^2;
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mag4 = abs(S4).^2;
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% begin calibrated color scale
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P1_dB = 10 * log10(mag1);
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P2_dB = 10 * log10(mag2);
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P3_dB = 10 * log10(mag3);
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P4_dB = 10 * log10(mag4);
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all_P_dB = [P1_dB(:); P2_dB(:); P3_dB(:); P4_dB(:)];
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p_dB_min = min(all_P_dB);
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p_dB_max = max(all_P_dB);
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% end power calibrated color scale
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if ~calculations_only
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% plot all figures like example shows
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figure(1);
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imagesc(T1, F1, P1_dB);
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axis ij;
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xlabel("Time [s]");
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ylabel("Freq. [Hz]");
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title("Spectrogram Trace 1");
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cb = colorbar;
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ylabel(cb, "Power [dB]");
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clim([p_dB_min p_dB_max]);
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xlim([0 0.05]);
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figure(2);
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imagesc(T2, F2, P2_dB);
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axis ij;
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xlabel("Time [s]");
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ylabel("Freq. [Hz]");
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title("Spectrogram Trace 2");
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cb = colorbar;
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ylabel(cb, "Power [dB]");
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clim([p_dB_min p_dB_max]);
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xlim([0 0.05]);
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figure(3);
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imagesc(T3, F3, P3_dB);
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axis ij;
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xlabel("Time [s]");
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ylabel("Freq. [Hz]");
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title("Spectrogram Trace 3");
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cb = colorbar;
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ylabel(cb, "Power [dB]");
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clim([p_dB_min p_dB_max]);
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xlim([0 0.05]);
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figure(4);
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imagesc(T4, F4, P4_dB);
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axis ij; % flip so its like the example fig
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xlabel("Time [s]");
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ylabel("Freq. [Hz]");
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title("Spectrogram Trace 4");
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cb = colorbar;
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ylabel(cb, "Power [dB]");
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clim([p_dB_min p_dB_max]);
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xlim([0 0.05]); % reduce view so its like the example fig
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end
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% 3.
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% taking the 10th percentile on the linear values or the logarithmic ones
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% should not make any difference
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noise_floor1_linear = prctile(mag1(:), 10);
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noise_floor2_linear = prctile(mag2(:), 10);
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noise_floor3_linear = prctile(mag3(:), 10);
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noise_floor4_linear = prctile(mag4(:), 10);
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noise_floor1 = 10 * log10(noise_floor1_linear);
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noise_floor2 = prctile(P2_dB(:), 10);
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noise_floor3 = prctile(P3_dB(:), 10);
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noise_floor4 = prctile(P4_dB(:), 10);
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% this is false -> linear avg on logarithmic values
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% noise_floor_avg = sum([noise_floor1 noise_floor2, noise_floor3, noise_floor4]) / 4;
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noise_floor_avg = 10 * log10(abs(sum([prctile(mag1(:), 10) prctile(mag2(:), 10) prctile(mag3(:), 10) prctile(mag4(:), 10)]) / 4));
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% 4.
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occupancy1 = sum(P1_dB(:) > noise_floor1 + 10) / numel(P1_dB) * 100;
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occupancy2 = sum(P2_dB(:) > noise_floor2 + 10) / numel(P2_dB) * 100;
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occupancy3 = sum(P3_dB(:) > noise_floor3 + 10) / numel(P3_dB) * 100;
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occupancy4 = sum(P4_dB(:) > noise_floor4 + 10) / numel(P4_dB) * 100;
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occupancies = [occupancy1 occupancy2 occupancy3 occupancy4];
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channels = [1 5 9 13];
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[occupancy_max, max_idx] = max(occupancies);
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busiest_channel = channels(max_idx);
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if ~calculations_only
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disp("Results Task 1:" + newline)
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disp("-- Trace duration ---")
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disp("Channel 1 duration: " + duration1 + "s")
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disp("Channel 5 duration: " + duration2 + "s")
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disp("Channel 9 duration: " + duration3 + "s")
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disp("Channel 13 duration: " + duration4 + "s" + newline)
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disp("--- Noise floor ---")
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disp("Distinct:")
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disp("Channel 1 noise floor: " + noise_floor1 + "dB")
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disp("Channel 5 noise floor: " + noise_floor2 + "dB")
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disp("Channel 9 noise floor: " + noise_floor3 + "dB")
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disp("Channel 13 noise floor: " + noise_floor4 + "dB" + newline)
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disp("Combined:")
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disp("Channel all noise floor: " + noise_floor_avg + "dB" + newline)
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disp("-- Occupancy ---")
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disp("Channel 1 occupancy: " + occupancy1 + "%")
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disp("Channel 5 occupancy: " + occupancy2 + "%")
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disp("Channel 9 occupancy: " + occupancy3 + "%")
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disp("Channel 13 occupancy: " + occupancy4 + "%" + newline)
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disp("Busiest channel: " + busiest_channel)
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end |