170 lines
6.3 KiB
Python
170 lines
6.3 KiB
Python
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# -*- coding: iso-8859-1 -*-
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from numpy import *
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from scipy.signal import *
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from scipy.optimize import *
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from scipy.fftpack import fft, ifft
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from os import path, rename
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def result():
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measurement = MeasurementResult('Magnetization')
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measurement_range = [0.0, 10e-6]
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measurement_ranging = False
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suffix = '' # output file name's suffix and...
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counter = 0 # counter for arrayed 2D experiments
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# npts = 0
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# loop over the incoming results:
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for timesignal in results:
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if not isinstance(timesignal,ADC_Result):
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continue
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# read experiment parameters:
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pars = timesignal.get_description_dictionary()
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# ---------------- digital filter ------------------
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# get actual sampling rate of timesignal:
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sampling_rate = timesignal.get_sampling_rate()
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# get user-defined spectrum width:
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spec_width = pars['SW']
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# specify cutoff frequency, in relative units:
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cutoff = spec_width / sampling_rate
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if cutoff < 1: # otherwise no filter applied
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# number of filter's coefficients:
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numtaps = 29
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# use firwin to create a lowpass FIR filter:
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fir_coeff = firwin(numtaps, cutoff)
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# downsize x according to user-defined spectral window:
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skip = int(sampling_rate / spec_width)
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timesignal.x = timesignal.x[::skip]
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for i in range(2):
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# apply the filter to ith channel:
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timesignal.y[i] = lfilter(fir_coeff, 1.0, timesignal.y[i])
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# zeroize first N-1 "corrupted" samples:
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timesignal.y[i][:numtaps-1] = 0.0
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# circular left shift of y:
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timesignal.y[i] = roll(timesignal.y[i], -(numtaps-1))
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# downsize y to user-defined number of samples (SI):
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timesignal.y[i] = timesignal.y[i][::skip]
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# update the sampling_rate attribute of the signal's:
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timesignal.set_sampling_rate(spec_width)
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# ----------------------------------------------------
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# rotate timesignal according to current receiver's phase:
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timesignal.phase(pars['rec_phase'])
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# provide timesignal to the display tab:
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data['Current scan'] = timesignal
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# accumulate...
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if not locals().get('accu'):
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accu = Accumulation()
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# skip dummy scans, if any:
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if pars['run'] < 0: continue
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# add up:
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accu += timesignal
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# provide accumulation to the display tab:
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data['Accumulation'] = accu
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# check whether accumulation is complete:
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# ------------------------------------------------------------------------------------
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# The hypercomplex technique implies recording two data sets for each t1 value.
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# One dataset (a cosine-modulated signal) is stored in odd records as Re, while
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# the other dataset (a sine-modulated signal) in even records as Im, totally 2*SI1
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# records. Henceforth, accu represents one such a record.
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# ------------------------------------------------------------------------------------
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if accu.n == pars['NS']:
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# compute the initial phase of FID:
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phi0 = arctan2(accu.y[1][0], accu.y[0][0]) * 180 / pi
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if not 'ref' in locals(): ref = phi0
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print 'phi0 = ', phi0
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# rotate every other record by 90<39> so that States algorithm is applicable:
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rec = (accu.job_id/accu.n)%(2*pars['SI1']) + 1
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if rec%2 == 0:
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accu.phase(90)
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coeff = 1.5
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accu.y[0] *= coeff # XY-balancing
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accu.y[1] *= coeff
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else: # baseline correction )))))
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tmp = fft(accu.y[0]+1j*accu.y[1])
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[start, stop] = len(accu.y[0])*array([0.4, 0.6])
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tmp -= mean(tmp.real[start:stop])
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tmp = ifft(tmp)
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accu.y[0] = tmp.real
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accu.y[1] = tmp.imag
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# check whether it is an arrayed experiment:
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var_key = pars.get('VAR_PAR')
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if var_key:
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# get variable parameter's value:
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var_value = pars.get(var_key)
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# provide signal recorded with this var_value to the display tab:
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data['Accumulation'+"/"+var_key+"=%e"%(var_value)] = accu
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# measure signal intensity vs. var_value:
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if measurement_ranging == True:
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[start, stop] = accu.get_sampling_rate() * array(measurement_range)
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measurement[var_value] = sum(accu.y[0][int(start):int(stop)])
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else:
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# measurement[var_value] = sum(accu.y[0][0:31])
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measurement[var_value+counter*1e-6] = sum(accu.y[0][0:31])
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# provide measurement to the display tab:
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data[measurement.get_title()] = measurement
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# update the file name suffix:
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counter2D = counter/(2*pars['SI1'])+1
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suffix = '_' + str(counter2D)
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counter += 1
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# save accu if required:
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outfile = pars.get('OUTFILE')
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if outfile:
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datadir = pars.get('DATADIR')
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# write raw data in Tecmag format:
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filename = datadir+outfile+suffix+'.tnt'
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accu.write_to_tecmag(filename,\
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nrecords=2*pars['SI1'],\
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frequency=pars['SW']+pars['O1'])
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# write parameters in a text file:
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filename = datadir+outfile+suffix+'.par'
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if path.exists(filename):
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rename(filename, datadir+'~'+outfile+suffix+'.par')
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fileobject = open(filename, 'w')
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for key in sorted(pars.iterkeys()):
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if key=='run': continue
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if key=='rec_phase': continue
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fileobject.write('%s%s%s'%(key,'=', pars[key]))
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fileobject.write('\n')
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fileobject.close()
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# reset accumulation:
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del accu
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pass
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