New file

Author: MarkRivers

docs/source/plot_quadem.pro

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+; Program to read HDF5 file for streamed quadEM data, plot it
+data = h5_getdata('J:\epics\scratch\quadEM_HDF5_001.h5', '/entry/data/data')
+help, data
+; Convert from a 3-D array [11, 2000, 200] to a 2-D array [11, 400000]
+data = reform(data, 11, 400000)
+; Extract the SumAll data
+sum_all = data[6, *]
+; Compute the time axis, 50 microseconds/sample
+time = findgen(400000) * 50e-6
+; Plot the first 0.5 second of data
+p1 = plot(time[0:9999], sum_all[0:9999], xtitle='Time (s)', ytitle='Sum of all diodes (nA)', $
+          title='Time Series', color='blue')
+p1.save, 'IDL_HDF5_time_plot.png'
+; Compute the FFT
+f = fft(sum_all)
+; Take the absolute value, first half of array
+f_abs = (abs(f))[0:199999]
+; Set the DC offset to 0
+f_abs[0] = 0
+; Compute the frequency axis. The sampling rate is 20 kHz so the Nyquist frequency is 10 kHz
+freq = findgen(200000)/199999. * 10000.
+; Plot the data out to 1 kHz
+p2 = plot(freq[0:19999], f_abs[0:199999], xtitle='Frequency (Hz)', ytitle='SumAll Intensity', $
+          title='Power Spectrum', color='red', /ylog, yrange=[.01,100])
+p2.save, 'IDL_HDF5_frequency_plot.png'
+end