59 lines
1.7 KiB
Matlab
59 lines
1.7 KiB
Matlab
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function txFrequency = findTxFrequency()
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% Setup:
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%
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% Place the HB100 in front of the Phaser - 0 degree azimuth.
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%
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% Notes:
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%
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% The frequency of the phaser is swept between 10 and 10.5 GHz. The peak
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% frequency is measured. This is assumed to be the frequency of the HB100.
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%
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% Setup the frequencies to scan.
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f_start = 10.e9;
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f_stop = 10.5e9;
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f_step = 5e6;
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fvec = f_start : f_step : f_stop;
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% Setup the antenna, setting the frequency to f_start.
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[rx,bf,~] = setupAntenna(f_start);
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% Setup variables for capturing scan amplitude and frequency.
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full_ampl = [];
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full_freqs = [];
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N = rx.SamplesPerFrame;
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% Loop through the frequency vector and save receive data at each center
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% frequency.
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for centerfrequency = fvec
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% The LO is set to 4x the Frequency setting.
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bf.Frequency = (centerfrequency + rx.CenterFrequency)/4;
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rx();
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% Capture the data, sum the channels, and convert to the frequency domain
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data = rx();
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data = sum(data,2);
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famplitude = mag2db(1/N * fftshift(abs(fft(data))));
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full_ampl = [full_ampl, famplitude];
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% Get the frequency span for this data sample
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df = rx.SamplingRate/N;
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band = (-rx.SamplingRate/2 : df : rx.SamplingRate/2 - df);
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freqspan = centerfrequency-band;
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full_freqs = [full_freqs, freqspan'];
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end
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% Get the max amplitude for each measurement
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[maxamplitudes,maxidxs] = max(full_ampl);
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% Get the max amplitude in the whole dataset
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[~,maxframeidx] = max(maxamplitudes);
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maxdatapointidx = maxidxs(maxframeidx);
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txFrequency = full_freqs(maxdatapointidx,maxframeidx);
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ax = axes(figure);
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plot(ax,full_freqs/1e9,full_ampl); xlabel('Frequency (GHz)'); ylabel('Amplitude (dB)');
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title(ax,['HB100 Frequency = ' num2str(txFrequency/1e9) 'GHz']);
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end
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