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florent_ba |
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%%% Finds light pulse bandwidth to estimate the needed RX BW
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lightpower = importdata("lightpulse_12V_100W.txt");
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frame_width = 10e-9;
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%% Crop of the original signal arround max. pulse value
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time = lightpower.data(:, 1);
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pwr = lightpower.data(:, 2);
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[peak_val, peak_index] = max(pwr);
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peak_time = time(peak_index);
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frame_start = peak_time - frame_width/2;
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frame_stop = peak_time + frame_width/2;
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[frame_start, frame_start_index] = min(abs(time - frame_start));
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[frame_stop, frame_stop_index] = min(abs(time - frame_stop));
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cropped_time = time(frame_start_index:frame_stop_index);
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cropped_time = cropped_time - cropped_time(1);
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cropped_pwr = pwr(frame_start_index:frame_stop_index);
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fprintf("Peak power : %f W at %f us\n", peak_val, peak_time*1e6)
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figure(1)
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plot(cropped_time*1e9, cropped_pwr, "-x")
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ylabel("Light power (W)")
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xlabel("Time (ns)")
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grid on
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figure(2)
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f = logspace(1, 10, 2000);
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Y = nufft(pwr, time, f);
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loglog(f.*1e-6, abs(Y));
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xlabel("Freq. (MHz)")
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grid on
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