def plot_x_and_psd_with_estimated_omega(x, sample_step=1, dt=1.0):
y = x[::sample_step]
F = freq(x, sample_step, dt)
T = 1.0 / F
pylab.clf()
# plot PSD
pylab.subplot(211)
pylab.psd(y, Fs=1.0 / sample_step / dt)
ylim = pylab.ylim()
pylab.vlines(F, *ylim)
pylab.ylim(ylim)
# plot time series
pylab.subplot(223)
pylab.plot(x)
# plot time series (three cycles)
n = int(T / dt) * 3
m = n // sample_step
pylab.subplot(224)
pylab.plot(x[:n])
pylab.plot(numpy.arange(0, n, sample_step)[:m], y[:m], 'o')
pylab.suptitle('F = %s' % F)
def RMSfromPSD(data, samplerate, graph=True):
y, x = pylab.psd(data, NFFT=nfft, Fs=samplerate)
t = np.linspace(0, len(data) * samplerate, num=len(data))
# Calculate the RMS
# The energy returned by PSD depends on FFT size
freqbandwidth = x[1]
y = y * freqbandwidth
# The energy returned by PSD depends on Samplerate
y = y / float(samplerate)
# Summing the power in freq domain to get RMS
rms = scipy.sqrt(y.sum())
if graph == True:
pylab.subplot(311)
pylab.plot(t, data)
pylab.subplot(312)
pylab.plot(MovingAverage(data, 100))
pylab.subplot(313)
pylab.psd(data, nfft, samplerate)
pylab.show()
return rms
def main():
sdr = LimeSDR()
sdr.enable_channel(False, 0, True)
sdr.set_LO_frequency(False, 0, 434e6)
sdr.set_antenna(False, 0, 2)
sdr.set_sample_rate(10e6, 4)
a, b, c = sdr.get_LPF_BW_range(False)
sdr.set_LPF_BW(False, 0, 10e6)
sdr.set_normalized_gain(False, 0, 0.7)
sdr.calibrate(False, 0, 10e6, 0)
stream = sdr.setup_stream(0, 1024 * 1024, 0.5, False, 2)
sdr.start_stream(stream)
start_time = datetime.datetime.now()
current_time = datetime.datetime.now()
while ((current_time - start_time).seconds < 2):
iq = sdr.receive_stream_iq(stream, 1024, 1000)
mpl.figure()
mpl.psd(iq, NFFT=1024, Fc=434, Fs=10)
mpl.show()
print(' signal mean:', sum(iq) / len(iq))
current_time = datetime.datetime.now()
sdr.close()
def plotLFPSpectrum():
colorspsd=array([[0.42,0.67,0.84],[0.42,0.83,0.59],[0.90,0.76,0.00],[0.90,0.32,0.00],[0.34,0.67,0.67],[0.42,0.82,0.83],[0.90,0.59,0.00],[0.33,0.67,0.47],[1.00,0.85,0.00],[0.71,0.82,0.41],[0.57,0.67,0.33],[1.00,0.38,0.60],[0.5,0.2,0.0],[0.0,0.2,0.5]])
lfpv=[[] for c in range(len(f.lfppops))]
# Get last modified .mat file if no input and plot
for c in range(len(f.lfppops)):
lfpv[c] = f.lfps[:,c]
lfptot = sum(lfpv)
# plot pops separately
plotPops = 0
if plotPops:
figure() # Open a new figure
for p in range(len(f.lfppops)):
psd(lfpv[p],Fs=200, linewidth= 2,color=colorspsd[p])
xlabel('Frequency (Hz)')
ylabel('Power')
h=axes()
h.set_yticklabels([])
legend(['L2/3','L5A', 'L5B', 'L6'])
# plot overall psd
figure() # Open a new figure
psd(lfptot,Fs=200, linewidth= 2)
xlabel('Frequency (Hz)')
ylabel('Power')
h=axes()
h.set_yticklabels([])
show()
def main():
sdr = RtlSdr()
print 'Configuring SDR...'
sdr.rs = 2.4e6
sdr.fc = 100e6
sdr.gain = 10
print ' sample rate: %0.6f MHz' % (sdr.rs/1e6)
print ' center frequency %0.6f MHz' % (sdr.fc/1e6)
print ' gain: %d dB' % sdr.gain
print 'Reading samples...'
samples = sdr.read_samples(256*1024)
print ' signal mean:', sum(samples)/len(samples)
print 'Testing callback...'
sdr.read_samples_async(test_callback, 256*1024)
try:
import pylab as mpl
print 'Testing spectrum plotting...'
mpl.figure()
mpl.psd(samples, NFFT=1024, Fc=sdr.fc/1e6, Fs=sdr.rs/1e6)
mpl.show()
except:
# matplotlib not installed/working
pass
print 'Done\n'
sdr.close()
def analyze_data(data):
""" analyzes characteristics of the (input) data
"""
example = 4
pylab.figure()
pylab.subplot(2, 1, 1)
pylab.plot(data[:, example])
pylab.subplot(2, 1, 2)
pylab.psd(data[:, example])
example = 3
pylab.figure()
pylab.subplot(2, 1, 1)
pylab.plot(data[:, example])
pylab.subplot(2, 1, 2)
pylab.psd(data[:, example])
# nicht wirklich aussagekraeftig:
# pylab.figure()
# pylab.subplot(2,1,1)
# pylab.plot(data.flatten())
# pylab.subplot(2,1,2)
# pylab.psd(data.flatten())
pylab.show()
exit(0)
def test_waveletfilter(plot=False):
# make test signal
Fs = 44100
freqs = [100,1000,2000,3000,4000,5000,6000,7000,8000,9000,10000]
t = np.arange(Fs,dtype=np.float64) / float(Fs) # 1 second
x = np.zeros(len(t))
for f in freqs:
x += np.sin(t * f * 2. * np.pi)
x /= len(freqs)
# print t,x
filtered = pywaveclus.dsp.wavelet.filt(x, minlevel=3, maxlevel=6)
assert len(filtered) == len(x),\
"len(filtered)[%i] != len(x)[%i]" % (len(filtered), len(x))
# TODO: test effectiveness of cutoffs
if plot:
import pylab as pl
pl.subplot(221)
pl.plot(t,x)
pl.subplot(222)
pl.psd(x,Fs=Fs)
pl.subplot(223)
pl.plot(t,filtered)
pl.subplot(224)
pl.psd(filtered,Fs=Fs)
pl.show()
def test_waveletfilter(plot=False):
# make test signal
Fs = 44100
freqs = [100, 1000, 2000, 3000, 4000, 5000, 6000, 7000, 8000, 9000, 10000]
t = np.arange(Fs, dtype=np.float64) / float(Fs) # 1 second
x = np.zeros(len(t))
for f in freqs:
x += np.sin(t * f * 2. * np.pi)
x /= len(freqs)
# print t,x
filtered = pywaveclus.dsp.wavelet.filt(x, minlevel=3, maxlevel=6)
assert len(filtered) == len(x),\
"len(filtered)[%i] != len(x)[%i]" % (len(filtered), len(x))
# TODO: test effectiveness of cutoffs
if plot:
import pylab as pl
pl.subplot(221)
pl.plot(t, x)
pl.subplot(222)
pl.psd(x, Fs=Fs)
pl.subplot(223)
pl.plot(t, filtered)
pl.subplot(224)
pl.psd(filtered, Fs=Fs)
pl.show()
def main():
sdr = RtlSdr()
print 'Configuring SDR...'
sdr.rs = 2.4e6
sdr.fc = 100e6
sdr.gain = 10
print ' sample rate: %0.6f MHz' % (sdr.rs / 1e6)
print ' center frequency %0.6f MHz' % (sdr.fc / 1e6)
print ' gain: %d dB' % sdr.gain
print 'Reading samples...'
samples = sdr.read_samples(256 * 1024)
print ' signal mean:', sum(samples) / len(samples)
print 'Testing callback...'
sdr.read_samples_async(test_callback, 256 * 1024)
try:
import pylab as mpl
print 'Testing spectrum plotting...'
mpl.figure()
mpl.psd(samples, NFFT=1024, Fc=sdr.fc / 1e6, Fs=sdr.rs / 1e6)
mpl.show()
except:
# matplotlib not installed/working
pass
print 'Done\n'
sdr.close()
def plot_x_and_psd_with_estimated_omega(x, sample_step=1, dt=1.0):
y = x[::sample_step]
F = freq(x, sample_step, dt)
T = 1.0 / F
pylab.clf()
# plot PSD
pylab.subplot(211)
pylab.psd(y, Fs=1.0 / sample_step / dt)
ylim = pylab.ylim()
pylab.vlines(F, *ylim)
pylab.ylim(ylim)
# plot time series
pylab.subplot(223)
pylab.plot(x)
# plot time series (three cycles)
n = int(T / dt) * 3
m = n // sample_step
pylab.subplot(224)
pylab.plot(x[:n])
pylab.plot(numpy.arange(0, n, sample_step)[:m], y[:m], 'o')
pylab.suptitle('F = %s' % F)
def main():
ntone = 64
buflen = 65536
v = np.zeros(buflen,dtype=np.complex)
phase = 2*pi*np.random.uniform(size=ntone)
for i in range(ntone):
j = i * buflen/ntone
u = np.exp(1.j*phase[i])
v[j] = u
ts = np.fft.ifft(v)
re,im = ts.real,ts.imag
maxval = np.max(np.abs([re,im]))
re *= 0.2*32767./maxval
im *= 0.2*32767./maxval
re = np.round(re).astype(dtype=np.int16)
im = np.round(im).astype(dtype=np.int16)
ts = re + 1.0j*im
d = np.vstack((re,im)).T
print d.shape
np.savetxt('rf_in.dat',d,fmt='%d',header='%d'%buflen)
pl.psd(ts)
pl.show()
def PlotPsd(self): """ compute and plot the matplotlib psd """ py.psd(self.data,512,self.length) py.show()
def PlotPsd(self):
"""
compute and plot the matplotlib psd
"""
py.psd(self.data, 512, self.length)
py.show()
def main():
print ' '
# Space Frequency
f1 = -50000 #Hz
# Mark Freq
f2 = 50000 #Hz
# Sample Rate
sampleRate = 2.4e6#Hz
# Baud Rate
baud=1200.0 #sps
# Number of Samples
numSamples = 256*256
packet=[1,0,1,1,0]
samples=[]
timeVector=[]
bitNum=0
timePassed=0
for i in range(numSamples):
timePassed=timePassed+1/sampleRate
if (timePassed>(1/baud)):
timePassed=0
print(packet[bitNum])
bitNum=bitNum+1
if (bitNum==len(packet)):
bitNum=0
if(packet[bitNum]==0):
samples.append(numpy.power(numpy.e,1j*2*numpy.pi*f1*i/sampleRate))
if(packet[bitNum]==1):
samples.append(numpy.power(numpy.e,1j*2*numpy.pi*f2*i/sampleRate))
pylab.figure()
pylab.psd(samples, NFFT=1024, Fc=1, Fs=sampleRate/(1e6))
pylab.show()
pylab.figure()
pylab.plot(samples)
pylab.show()
print 'Creating IQ.csv...' + '\n'
f=open('IQ_gen.csv','w')
f.write('Sample Rate,' + str(sampleRate)+ '\nCenter Freq,'+str((f2+f1)/2)+ '\nGain,'+str(20)+ '\nSamples Per Sweep,'+str(numSamples)+'\nNumber of Sweeps,'+str(numSamples)+str('\n\n'))
f.write('Time Elapsed, Sample\n')
print 'Writing CSV data...' + '\n'
for j in range(numSamples):
f.write(str(j/sampleRate)+','+str(samples[j])+ '\n')
def test_psd():
from numpy import linspace,sin
from pylab import psd,show
x = linspace(0,100,10000)
y = sin(x*100)/100.
psd(y,NFFT=256,scale_by_freq=True)
show()
def plot_sample0(samp):
N = min(len(samp), 256)
fs = 48000
pl.subplot(211)
pl.grid()
pl.plot(samp)
pl.subplot(212)
pl.grid()
#pl.ylim((-50, 50))
pl.psd(samp, N, window=pl.blackman(N), Fs=fs)
def plot_psd(self,fc,samp_scale=256):
if self.sdr.center_freq != fc:
self.sdr.center_freq = fc
samples = self.sdr.read_samples(samp_scale*1024)
# use matplotlib to estimate and plot the PSD
psd(samples, NFFT=1024, Fs=self.sdr.sample_rate/1e6, \
Fc=self.sdr.center_freq/1e6)
xlabel('Frequency (MHz)')
ylabel('Relative power (dB)')
show()
def main():
sdr = RtlSdr()
print ' '
# Bandwidth/Sample Rate
sdr.rs = 2e6
# Center Freq
sdr.fc = 907.941e6
# Gain
sdr.gain = 20
numSamplesPerSweep = 256*256*8
numSweeps = 7
samples=[0]*numSweeps*numSamplesPerSweep
timeVector=[]
print 'Capturing data for ' + str(numSweeps) + ' sweeps...' + '\n'
for i in range(numSweeps):
samples[i*numSamplesPerSweep:(i+1)*numSamplesPerSweep-1]=(sdr.read_samples(numSamplesPerSweep))
timeVector.append(time.clock())
# print samples
print 'Creating IQ.csv...' + '\n'
f=open('IQ.csv','w')
print 'Writing CSV data...' + '\n'
f.write('Sample Rate,' + str(sdr.rs)+ '\nCenter Freq,'+str(sdr.fc)+ '\nGain,'+str(sdr.gain)+ '\nSamples Per Sweep,'+str(numSamplesPerSweep)+'\nNumber of Sweeps,'+str(numSweeps)+str('\n\n'))
f.write('Time Elapsed, Sample\n')
for i in range(numSweeps):
for j in range(numSamplesPerSweep-1):
f.write(str(timeVector[i]-timeVector[0]+j/sdr.rs)+','+str(samples[i*numSamplesPerSweep+j])+ '\n')
f.write(str(timeVector[i]-timeVector[0]+j/sdr.rs)+','+str(samples[(i+1)*numSamplesPerSweep-1]) + '\n')
f.close
print 'CSV file created; program terminating...' + '\n'
pylab.figure()
pylab.psd(samples, NFFT=1024, Fc=sdr.fc/(1e6), Fs=sdr.rs/(1e6))
pylab.show()
pylab.figure()
pylab.plot(samples)
pylab.show()
sdr.close()
def numsyls(path1):
fils1 = [x for x in os.listdir(path1) if x[-4:] == '.wav']
fils1 = fils1[:120]
filename1 = path1.split('/')[-2]
datano = 15000 # maximum number of syllables to be analyzed
# get syllables from all of the songs in folder
syls1 = []
objss1 = []
for file in fils1:
song = impwav(path1 + file)
if len(song[0]) < 1: break
syls, objs, frq = (getsyls(song))
objss1.append(objs)
syls1.append([frq] + syls)
# convert syllables so PSDs
segedpsds1 = []
for x in syls1[:datano]:
fs = x[0]
nfft = int(round(2 ** 14 / 32000.0 * fs))
segstart = int(round(600 / (fs / float(nfft))))
segend = int(round(16000 / (fs / float(nfft))))
psds = [psd(norm(y), NFFT=nfft, Fs=fs) for y in x[1:]]
spsds = [norm(n[0][segstart:segend]) for n in psds]
for n in spsds: segedpsds1.append(n)
if len(segedpsds1) > datano: break
segedpsds, sylno_bic = EMofgmmcluster(segedpsds1)
print(filename1 + '\t' + str(sylno_bic))
def psd(self,xstr,nfft=256,noverlap=0,coarsable=False):
"""Return the PSD(power spectral density) of the time-series
Positional parameter:
xstr -- string naming the observable, either 'A'or 'E'
Keyword parameters:
nfft -- length of the fast fourier transform (fft) (default 256)
noverlap -- number of data points overlapping between segments (default 0)
coarsable -- return the PSD as a Coarsable object (default False)
OUTPUT:
f -- frequencies
P -- PSD
Note:
The PSD is calculated using pl.psd() with an additional factor of dt in the normalisation.
This gives the correct dimension.
"""
x = getattr(self,xstr)
fs = 1. / x.Cadence1
P , f = pl.psd( x.data , nfft , fs , noverlap=noverlap , scale_by_freq=False )
P = P / fs
if coarsable:
scale = {'Offset1' : f[0] ,
'Cadence1': f[1] - f[0] }
f = ASI.Coarsable( f , **scale )
P = ASI.Coarsable( P , **scale )
return f , P
def psd(self, xstr, nfft=256, noverlap=0, coarsable=False):
"""Return the PSD(power spectral density) of the time-series
Positional parameter:
xstr -- string naming the observable, either 'A'or 'E'
Keyword parameters:
nfft -- length of the fast fourier transform (fft) (default 256)
noverlap -- number of data points overlapping between segments (default 0)
coarsable -- return the PSD as a Coarsable object (default False)
OUTPUT:
f -- frequencies
P -- PSD
Note:
The PSD is calculated using pl.psd() with an additional factor of dt in the normalisation.
This gives the correct dimension.
"""
x = getattr(self, xstr)
fs = 1. / x.Cadence1
P, f = pl.psd(x.data, nfft, fs, noverlap=noverlap, scale_by_freq=False)
P = P / fs
if coarsable:
scale = {'Offset1': f[0], 'Cadence1': f[1] - f[0]}
f = ASI.Coarsable(f, **scale)
P = ASI.Coarsable(P, **scale)
return f, P
def main():
f = open('TRAJEC.xyz','r')
t = []
dr = []
lines = f.readlines()
f.close()
dr = []
out = open('f_bond.dat','w')
for i in range(len(lines)/4):
natom = int(lines.pop(0))
out.write(str(int(lines.pop(0)))+' ')
typat1,x1,y1,z1 = lines.pop(0).split()
typat2,x2,y2,z2 = lines.pop(0).split()
r = ( (float(x1)-float(x2))**2 + (float(y1)-float(y2))**2 + (float(z1)-float(z2))**2 )**0.5
out.write(str(abs(r))+'\n')
dr.append(abs(r))
for i in range(natom-2): lines.pop(0)
out.close()
pxx, f = pylab.psd(dr,NFFT=32768)
pylab.savefig('psd.png')
out2 = open('psd.dat','w')
for i in range(len(pxx)):
out2.write(str(pxx[i])+' '+str(f[i])+'\n')
out2.close()
def do_it(filename):
dic1, _ = read_tiq(filename, 1, 1024, 1)
center1 = dic1['center']
fs1 = dic1['fs']
nframes_tot = dic1['nframes_tot']
naf = nacnt = np.array([])
for i in range(1, nframes_tot, 100):
dic1, _ = read_tiq(filename, 1, 1024, i)
x1 = dic1['data']
Pxx1, freqs1 = psd(x1, NFFT=1024, Fs=fs1, noverlap=512)
naf = np.append(naf, freqs1[Pxx1.argmax()])
nacnt = np.append(nacnt, i)
naf = naf + center1
fig = plt.figure()
ax = fig.add_subplot(1, 1, 1)
ax.plot(nacnt, naf, 'r.')
ax.annotate('ISO at: {} [MHz]'.format(naf.max() / 1.0e6), xy=(nacnt[naf.argmax()], naf.max()), xycoords='data',
xytext=(0.5, 0.5), textcoords='figure fraction',
arrowprops=dict(width=1, headwidth=5, edgecolor='blue', facecolor='blue', shrink=0.05))
plt.ylabel('Frequency [Hz]')
plt.xlabel('Frame Number')
plt.title('File: ' + filename.split('/')[3])
plt.grid(True)
fig.savefig(os.path.splitext(filename)[0] + '.pdf')
plt.show()
def importData(self, filename):
self.filename = filename
ifile = open(filename, "r")
reader = csv.reader(ifile)
for row in reader:
if len(row) > 1:
if row[1].lstrip() == "XXX":
break
#self.data_array = fromiter((int(row[1].lstrip(), 16) for row in reader), int)
self.raw_data = [[int(num.lstrip(),16) for num in row if num != ' '] for row in reader]
self.adc_int_values = [row[1] for row in self.raw_data]
self.adc_raw_values = [row[2:] for row in self.raw_data]
self.adc_raw_values = reshape(array(self.adc_raw_values), array(self.adc_raw_values).size, order='F').reshape(12,-1)
for i in arange(12):
for j in arange(len(self.adc_raw_values[0])):
self.adc_raw_values[i][j] = self.adc_raw_values[i][j] + 2*i
for i in range(len(self.adc_int_values)):
if self.adc_int_values[i] >= 2048:
self.adc_int_values[i] = self.adc_int_values[i] - 4096
self.data_psd = psd(self.adc_int_values, 2048, 50000000, label=self.filename)
def plot_x_and_psd_with_estimated_omega(self, x, sample_step=1, dt=1.0):
y = x[::sample_step]
F = self.freq(x, sample_step, dt)
pylab.clf()
# plot PSD
pylab.subplot(211)
pylab.psd(y, Fs=1.0 / sample_step / dt)
ylim = pylab.ylim()
pylab.vlines(F, *ylim)
pylab.ylim(ylim)
# plot time series
pylab.subplot(223)
pylab.plot(x)
def do_it(filename):
dic1, _ = read_tiq(filename, 1, 1024, 1)
center1 = dic1['center']
fs1 = dic1['fs']
nframes_tot = dic1['nframes_tot']
naf = nacnt = np.array([])
for i in range(1, nframes_tot, 100):
dic1, _ = read_tiq(filename, 1, 1024, i)
x1 = dic1['data']
Pxx1, freqs1 = psd(x1, NFFT=1024, Fs=fs1, noverlap=512)
naf = np.append(naf, freqs1[Pxx1.argmax()])
nacnt = np.append(nacnt, i)
naf = naf + center1
fig = plt.figure()
ax = fig.add_subplot(1, 1, 1)
ax.plot(nacnt, naf, 'r.')
ax.annotate('ISO at: {} [MHz]'.format(naf.max() / 1.0e6),
xy=(nacnt[naf.argmax()], naf.max()),
xycoords='data',
xytext=(0.5, 0.5),
textcoords='figure fraction',
arrowprops=dict(width=1,
headwidth=5,
edgecolor='blue',
facecolor='blue',
shrink=0.05))
plt.ylabel('Frequency [Hz]')
plt.xlabel('Frame Number')
plt.title('File: ' + filename.split('/')[3])
plt.grid(True)
fig.savefig(os.path.splitext(filename)[0] + '.pdf')
plt.show()
def main():
sdr = RtlSdr()
print('Configuring SDR...')
sdr.DEFAULT_ASYNC_BUF_NUMBER = 16
sdr.rs = 2.5e6 ## sampling rate
sdr.fc = 100e6 ## center frequency
sdr.gain = 10
print(' sample rate: %0.6f MHz' % (sdr.rs/1e6))
print(' center frequency %0.6f MHz' % (sdr.fc/1e6))
print(' gain: %d dB' % sdr.gain)
print('Reading samples...')
samples = sdr.read_samples(256*1024)
print(' signal mean:', sum(samples)/len(samples))
filter = signal.firwin(5, 2* array([99.5,100.5])/sdr.rs,pass_zero=False)
mpl.figure()
for i in range(100):
print('Testing spectrum plotting...')
mpl.clf()
signal2 = convolve(sdr.read_samples(256*1024),filter)
psd = mpl.psd(signal2, NFFT=1024, Fc=sdr.fc/1e6, Fs=sdr.rs/1e6)
mpl.pause(0.001)
#mpl.plot(sdr.read_samples(256*1024))
mpl.show(block=False)
print('Done\n')
sdr.close()
def WelchPeriodogram(data, NFFT=None, sampling=1., **kargs):
r"""Simple periodogram wrapper of numpy.psd function.
:param A: the input data
:param int NFFT: total length of the final data sets (padded
with zero if needed; default is 4096)
:param str window:
:Technical documentation:
When we calculate the periodogram of a set of data we get an estimation
of the spectral density. In fact as we use a Fourier transform and a
truncated segments the spectrum is the convolution of the data with a
rectangular window which Fourier transform is
.. math::
W(s)= \frac{1}{N^2} \left[ \frac{\sin(\pi s)}{\sin(\pi s/N)} \right]^2
Thus oscillations and sidelobes appears around the main frequency. One aim of t he tapering is to reduced this effects. We multiply data by a window whose sidelobes are much smaller than the main lobe. Classical window is hanning window. But other windows are available. However we must take into account this energy and divide the spectrum by energy of taper used. Thus periodogram becomes :
.. math::
D_k \equiv \sum_{j=0}^{N-1}c_jw_j \; e^{2\pi ijk/N} \qquad k=0,...,N-1
.. math::
P(0)=P(f_0)=\frac{1}{2\pi W_{ss}}\arrowvert{D_0}\arrowvert^2
.. math::
P(f_k)=\frac{1}{2\pi W_{ss}} \left[\arrowvert{D_k}\arrowvert^2+\arrowvert{D_{N-k}}\arrowvert^2\right] \qquad k=0,1,..., \left( \frac{1}{2}-1 \right)
.. math::
P(f_c)=P(f_{N/2})= \frac{1}{2\pi W_{ss}} \arrowvert{D_{N/2}}\arrowvert^2
with
.. math::
{W_{ss}} \equiv N\sum_{j=0}^{N-1}w_j^2
.. plot::
:width: 80%
:include-source:
from spectrum import WelchPeriodogram, marple_data
psd = WelchPeriodogram(marple_data, 256)
"""
from pylab import psd
spectrum = Spectrum(data, sampling=1.)
P = psd(data, NFFT, Fs=sampling, **kargs)
spectrum.psd = P[0]
#spectrum.__Spectrum_sides = 'twosided'
return P, spectrum
def test_NFFT(s):
from numpy import arange,power
from pylab import psd,show
import matplotlib.pyplot as plt
import seaborn as sns
sns.__version__
NFFTs = power(2,arange(6,10))
for NFFT in NFFTs[::-1]:
psd(s,NFFT,scale_by_freq=True,Fs=10000)
plt.xlim(200,5000)
plt.ylim(-45,-35)
plt.semilogx()
show()
def plot_frame(n=-1):
j=225 # z=10
k=28 # x=1
vis = netCDF4.Dataset('vis.nc')
#values
U = vis.variables['U'][n,0,:,:]
UHTS = vis.variables['U'][:,0,j,:]
UVTS = vis.variables['U'][:,0,:j,k]
#grid stuff
x = vis.variables['x'][:]
yf = vis.variables['yf'][:]
t = vis.variables['t'][:]
vis.close
interpolation = 'nearest'
aspect = 'auto'
dt = np.mean(np.diff(t))
plt.subplot(311)
#plt.plot(k,y,'k-',linewidth=2)
#plt.plot(x,j,'k-',linewidth=2)
plt.axhline(y=yf[j])
plt.axvline(x=x[k])
#plot horizontal velocity
plt.ylim(ymin=-7,ymax = 0)
plt.imshow(U, origin='lower', aspect=aspect,
interpolation=interpolation,
vmin = -UMAX, vmax = UMAX,
extent=[x[0], x[-1], yf[0], yf[-1]])
plt.colorbar()
plt.title('U, frame %d' % n)
plt.xlabel('x')
plt.ylabel('z')
#compute power spectral density x
plt.subplot(312)
plt.ylim(ymin=-230,ymax=10)
plt.xlim(xmin=0,xmax=10)
plt.psd(UHTS[n,:], NFFT=len(UHTS[n,:]), Fs=(2*np.pi)/(dt))
#compute power spectral density z
plt.subplot(313)
plt.ylim(ymin=-80,ymax=0)
#plt.xlim(xmin=0,xmax=10)
plt.psd(UVTS[n,:], NFFT=len(UVTS[n,:]), Fs=(2*np.pi)/(dt))
def main():
print ' '
# Space Frequency
f1 = -0.1e6 #Hz
# Mark Freq
f2 = 0.1e6 #Hz
# Sample Rate
sampleRate = 3e6#Hz
# Baud Rate
baud=2.0 #sps
# Number of Samples
numSamples = 3000000
packet=[1,0]
samples=[]
timeVector=[]
bitNum=0
timePassed=0
for i in range(numSamples):
timePassed=timePassed+1/sampleRate
if (timePassed>(1/baud)):
timePassed=0
print(packet[bitNum])
bitNum=bitNum+1
if (bitNum==len(packet)):
bitNum=0
if(packet[bitNum]==0):
samples.append(numpy.power(numpy.e,1j*2*numpy.pi*f1*i/sampleRate))
if(packet[bitNum]==1):
samples.append(numpy.power(numpy.e,1j*2*numpy.pi*f2*i/sampleRate))
pylab.figure()
pylab.psd(samples, NFFT=1024, Fc=0, Fs=sampleRate/(1e6))
pylab.show()
sampleArray=numpy.array(samples)
sampleArray.tofile('txData.bin')
def collectSignal(freq, freq_file_path, mag_file_path):
# Define function for writing signal data into file
def write_data(data_points, magnitudeData, frequencyData, mag_file,
freq_file):
i = 0
mag_file.write('[')
freq_file.write('[')
while i < data_points - 1:
mag_file.write("%s, " % magnitudeData[i])
freq_file.write("%s, " % frequencyData[i])
i += 1
mag_file.write('%s]\n' % magnitudeData[i])
freq_file.write('%s]\n' % frequencyData[i])
sdr = RtlSdr()
# Configure SDR
sdr.sample_rate = 2.4e6 # Hz
sdr.center_freq = freq # Hz
sdr.freq_correction = 60 # PPM
sdr.gain = 4 # 'auto'
# Initialize
data_points = 1024
samples = sdr.read_samples(256 * data_points)
mag_file_path = mag_file_path + "magdata.txt"
freq_file_path = freq_file_path + "freqdata.txt"
### *** IMPORTANT *** (for later, when optimizing)
### I'm not sure if we should leave this outside of the function
### and move it to the end of the main code, after the flight path
### ends. Idk the impact of leaving the SDR open/on for an extended
### period of time. If we move sdr.close() outside, we have to
### remember to also move the above code outside as well.
### Leaving this line within this function should be fine for now.
sdr.close()
# PSD plot data
psddata = psd(samples,
NFFT=data_points,
Fs=sdr.sample_rate / 1e6,
Fc=sdr.center_freq / 1e6)
# Extracting pertinent information from the PSD plot calculation
magnitudeData = psddata[0]
frequencyData = psddata[1]
# Check for .txt file and write data
# Magnitude has not been converted to dB yet. To convert, 10*log(magnitude). This comment is for Ron.
if Path(mag_file_path).is_file() and Path(freq_file_path).is_file():
with open(mag_file_path, 'a') as mag_file, open(freq_file_path,
'a') as freq_file:
write_data(data_points, magnitudeData, frequencyData, mag_file,
freq_file)
else:
with open(mag_file_path, 'w') as mag_file, open(freq_file_path,
'w') as freq_file:
write_data(data_points, magnitudeData, frequencyData, mag_file,
freq_file)
def get_psd(wav, fs, nfft=PSD_NFFT, plot=False): """ Given a wav, returns a tuple of the power spectral density using Welch's method and associated frequencies. """ (pxx, fxx) = pylab.psd(wav, nfft, fs) if plot: pylab.show() return (pxx, fxx)
def display_power_density(self,widget):
print 'trying'
from pylab import psd,show,figure,ion,title
nfft = int(self.builder.get_object('entry1').get_text())
srate = float(self.builder.get_object('entry2').get_text())
chind = self.chlabels.index(self.chan_sel);print 'chind',chind
data = self.data[:,chind]
figure()
pow,freq=psd(data, NFFT=nfft, Fs=srate);ion();
title('Spectral Power of Channel: '+self.chan_sel)
show()
def get_psd(wav, fs, nfft=PSD_NFFT, plot=False):
"""
Given a wav, returns a tuple of the power spectral density using Welch's method and associated frequencies.
"""
(pxx, fxx) = pylab.psd(wav, nfft, fs)
if plot:
pylab.show()
return (pxx, fxx)
def testDataRead():
channels = [0,1,2,3,4,5,6,7]
import pylab
for i in range(50):
print i
data = readFile(datfile,start=1*i,stop=1*(i+1))
for c in channels:
pylab.subplot(4,2,c+1)
px,freq = pylab.psd(data[c])
pylab.show()
def shifted_horizontal_psd(n=-1):
j1 = 225
j2 = 175
j3 = 125
vis = netCDF4.Dataset('vis.nc')
U1 = vis.variables['U'][:,0,j1,:]
U2 = vis.variables['U'][:,0,j2,:]
U3 = vis.variables['U'][:,0,j3,:]
x = vis.variables['x'][:]
yf = vis.variables['yf'][:]
t = vis.variables['t'][:]
vis.close
dt = np.mean(np.diff(t))
plt.subplot(311)
plt.ylim(ymin=-230,ymax=10)
plt.xlim(xmin=0,xmax=10)
plt.psd(U1[n,:], NFFT = len(U1[n,:]), Fs=(2*np.pi)/(dt))
plt.subplot(312)
plt.ylim(ymin=-230,ymax=10)
plt.xlim(xmin=0,xmax=10)
plt.psd(U2[n,:], NFFT = len(U2[n,:]), Fs=(2*np.pi)/(dt))
plt.subplot(313)
plt.ylim(ymin=-230,ymax=10)
plt.xlim(xmin=0,xmax=10)
plt.psd(U3[n,:], NFFT = len(U3[n,:]), Fs=(2*np.pi)/(dt))
def test_callback(samples, rtlsdr_obj):
#print(samples)
mpl.clf()
#dataset.extend(samples)
x = samples
yb1 = signal.convolve(x, filterB1)
#mpl.psd(yb1, NFFT=1024, Fc=0, Fs=48e3)
yn1 = downsample(yb1, 10)
#mpl.psd(yn1, NFFT=1024, Fc=0, Fs=sdr.rs/10)
zdis = discrim(yn1)
#mpl.psd(zdis, NFFT=1024, Fc=0, Fs=sdr.rs/10)
zb2 = signal.convolve(zdis, filterB2)
zn2 = downsample(zb2, 5)
mpl.psd(x)
mpl.psd(zn2, NFFT=1024, Fc=0, Fs=48e3)
mpl.plot(zdis)
mpl.pause(0.0001)
mpl.show(block=False)
zn2 /= npmax(abs(zn2),axis=0)
# complex2wav("teste.wav",48e3,zn2)
play(zn2, fs=48e3)
def testReadAndDetrendAndBP(detrend_length=10,s_freq=100000):
import copy,pylab
channels = [0,1,2,3,4,5,6,7]
data = readFile(datfile,start=0,stop=1,sfreq = s_freq)
#detrendData = copy.deepcopy(data)
bipolar = generateBipolar(data)
pylab.plot(bipolar)
detrend(data,detrend_Kernel_Length = detrend_length,sampling_Frequency = s_freq)
bipolar = generateBipolar(data)
pylab.psd(bipolar[0])
pylab.psd(bipolar[1])
pylab.psd(bipolar[2])
pylab.psd(bipolar[3])
pylab.show()
def get_fft_data(self, scan=False):
try:
[Y, F] = plt.psd(self.read_samples(), NFFT=1024, Fs=int(self.sample_rate)/1e6, \
Fc=int(self.center_freq)/1e6, color='k')
if scan: max_freqs = self.find_peaks(plt, Y, F, n=self.sensivity)
plt.xlabel('Frequency (MHz)')
plt.ylabel('Relative power (dB)')
plt.savefig(self.static_dir + '/img/fft.png', bbox_inches='tight', pad_inches = 0)
plt.clf()
encoded = base64.b64encode(open(self.static_dir + '/img/fft.png', "rb"). \
read()).decode("utf-8")
return encoded if not scan else [encoded, max_freqs]
except Exception as e:
self.logcl.log("Failed to get graph data.\n" + str(e), 'error')
def test(sdr=None):
if sdr is None:
if is_travisci():
sdr_cls = DummyRtlSdr
else:
sdr_cls = RtlSdr
sdr = build_test_sdr(sdr_cls)
print('Configuring SDR...')
sdr.rs = 2.4e6
sdr.fc = 100e6
sdr.gain = 10
print(' sample rate: %0.6f MHz' % (sdr.rs/1e6))
print(' center frequency %0.6f MHz' % (sdr.fc/1e6))
print(' gain: %d dB' % sdr.gain)
print('Reading samples...')
samples = sdr.read_samples(256*1024)
print(' signal mean:', sum(samples)/len(samples))
print('Testing callback...')
async_read_test(sdr, 256*1024)
try:
import pylab as mpl
print('Testing spectrum plotting...')
mpl.figure()
mpl.psd(samples, NFFT=1024, Fc=sdr.fc/1e6, Fs=sdr.rs/1e6)
mpl.show()
except:
# matplotlib not installed/working
pass
print('Done\n')
sdr.close()
def test(sdr=None):
if sdr is None:
if is_travisci():
sdr_cls = DummyRtlSdr
else:
sdr_cls = RtlSdr
sdr = build_test_sdr(sdr_cls)
print('Configuring SDR...')
sdr.rs = 2.4e6
sdr.fc = 100e6
sdr.gain = 10
print(' sample rate: %0.6f MHz' % (sdr.rs / 1e6))
print(' center frequency %0.6f MHz' % (sdr.fc / 1e6))
print(' gain: %d dB' % sdr.gain)
print('Reading samples...')
samples = sdr.read_samples(256 * 1024)
print(' signal mean:', sum(samples) / len(samples))
print('Testing callback...')
async_read_test(sdr, 256 * 1024)
try:
import pylab as mpl
print('Testing spectrum plotting...')
mpl.figure()
mpl.psd(samples, NFFT=1024, Fc=sdr.fc / 1e6, Fs=sdr.rs / 1e6)
mpl.show()
except:
# matplotlib not installed/working
pass
print('Done\n')
sdr.close()
def transform_target_data_old(audiofile,analyze=0):
""" Calculates the target data (in MIDI pitch classes) out of the REF.txt files.
(for the old datasets of Ellis and MIREX)
"""
target_file = DATA_PATH + audiofile[:-4] + "REF.txt"
data = read_array(target_file)
# remove time axes and convert to midi
data = data[:,1]
midi_data = audiotools.freq_to_midi(data)
midi_data = np.round(midi_data)
if analyze:
pylab.plot(midi_data)
# get the unique element (nr. of different notes) of the piece
unique = list(set(midi_data))
target = np.zeros((len(midi_data), len(unique)))
for n in range( len(midi_data) ):
ind = unique.index( midi_data[n] )
target[n,ind] = 1
if analyze:
print "classes:",len(unique)
pylab.figure()
pylab.psd(target.flatten())
pylab.show()
exit(0)
savefile = OUTPUT_DIR + audiofile[:-4] + "_STFT.dat"
data = shelve.open(savefile)
lenge = data["features"].shape[0]
data["targets"] = target[:lenge]
data["target_midi"] = midi_data[:lenge]
data["pitch_classes"] = unique
data.close()
def main(): print ' ' # Space Frequency f1 = 2e4 #Hz # Sample Rate sampleRate = 2e6#Hz # Number of Samples numSamples = 256 packet=[0] samples=[] timeVector=[] bitNum=0 timePassed=0 for i in range(numSamples): samples.append(numpy.power(numpy.e,1j*2*numpy.pi*f1*i/sampleRate)) pylab.figure() pylab.psd(samples, NFFT=256, Fc=1, Fs=sampleRate/(1e6)) pylab.show() pylab.figure() pylab.plot(samples) pylab.show() pylab.figure() pylab.plot(numpy.fft.fft(samples,8)) pylab.show()
def plotpsd():
colorspsd = array([[0.42, 0.67, 0.84], [0.42, 0.83, 0.59],
[0.90, 0.76, 0.00], [0.90, 0.32, 0.00],
[0.34, 0.67, 0.67], [0.42, 0.82, 0.83],
[0.90, 0.59, 0.00], [0.33, 0.67, 0.47],
[1.00, 0.85, 0.00], [0.71, 0.82, 0.41],
[0.57, 0.67, 0.33], [1.00, 0.38, 0.60], [0.5, 0.2, 0.0],
[0.0, 0.2, 0.5]])
lfpv = [[] for c in range(len(s.lfppops))]
# Get last modified .mat file if no input and plot
for c in range(len(s.lfppops)):
lfpv[c] = s.lfps[:, c]
lfptot = sum(lfpv)
# plot pops separately
plotPops = 0
if plotPops:
figure() # Open a new figure
for p in range(len(s.lfppops)):
psd(lfpv[p], Fs=200, linewidth=2, color=colorspsd[p])
xlabel('Frequency (Hz)')
ylabel('Power')
h = axes()
h.set_yticklabels([])
legend(['L2/3', 'L5A', 'L5B', 'L6'])
# plot overall psd
figure() # Open a new figure
psd(lfptot, Fs=200, linewidth=2)
xlabel('Frequency (Hz)')
ylabel('Power')
h = axes()
h.set_yticklabels([])
show()
def plot_fft(self, reals, imags, timea, sample_rate, fc, NFFT, myfile):
M = len(reals) / NFFT
for i in range(0, int(M)):
iq_samples = np.array([
(re + 1j * co) for re, co in zip(reals, imags)
])[i * NFFT:(i + 1) * NFFT]
x = pylab.psd(iq_samples,
NFFT=NFFT,
Fs=sample_rate / 1e6,
Fc=fc,
window=mlab.window_hanning)
totalpower = self.totalpower(x[0])
#print i, totalpower
myfile.write("%s\n" % totalpower)
myfile.flush()
pylab.close()
def EMofgmmcluster(array_of_syls):
"""takes an array of segmented sylables, fits a series of
gaussian mixture models with an increasing number of mixtures,
and identifies the best number of mixtures to describe the data
by BIC. If data is limiting, we don't recommend using cross validation
for BIC. If you have sufficient data 3 fold cross validated BIC values
compare well with un-cross validated values and human assesment of syllable
number. If data are limiting, cross validated values underestimate
the number of syllables relative to human assessment or non-cross
validated BIC values.
"""
nfft = 2 ** 14
fs = 32000
segstart = int(600 / (fs / nfft))
segend = int(16000 / (fs / nfft))
welchpsds = [psd(x, NFFT=nfft, Fs=fs) for x in array_of_syls]
segedpsds1 = [norm(x[0][segstart:segend]) for x in welchpsds]
models = range(2, 22)
# select the first 50 syllables of the reference song as the basis set
basis_set = segedpsds1[:50]
# select a random set of 50 syllablse as the basis set
# basis_set=[segedpsds1[rnd.randint(0,len(segedpsds1))] for x in range(50)]
d = sc.spatial.distance.cdist(segedpsds1, basis_set, 'sqeuclidean')
s = 1 - d / np.max(d) * 1000
bic = []
# xv=3
for x in models:
bics = []
# this commented section implements cross validation for the BIC values
'''ss=chunks(s,len(s)/xv)
for y in range(len(ss)):
testset=ss[y]
trainset=[]
[trainset.extend(ss[n]) for n in [z for z in range(len(ss)) if z!=y]]
gmm = mixture.GMM(n_components=x, n_iter=100000,n_init=5, covariance_type='full')
gmm.fit(np.array(s))
bics.append(gmm.bic(np.array(s)))
bic.append(np.mean(bics))'''
gmm = GMM(n_components=x, max_iter=100000, n_init=5, covariance_type='full')
gmm.fit(np.array(s))
bic.append(gmm.bic(np.array(s)))
return segedpsds1, bic.index(min(bic)) + 2
def display_power_density(self,widget):
#self.create_draw_frame(widget)
#return
print 'trying'
from pylab import psd,show,figure,ion,title
nfft = int(self.builder.get_object('entry1').get_text())
srate = float(self.builder.get_object('entry2').get_text())
chind = self.chlabels.index(self.chan_sel);print 'chind',chind
data = self.data[:,chind]
print 'NFFT',nfft,'SRATE',srate
#figure()
f = figure(figsize=(20,10), dpi=45)
#title('Spectral Power of Channel: '+self.chan_sel)
a = f.add_subplot(111)
pow,freq=psd(data, NFFT=nfft, Fs=srate)
f.show()
def psd(data, dt=0.005, NFFT=512, plot=1):
"""
Compute power spectrum destinity for input time array.
This function just wraper for pylab.psd implementation
Paramters:
----------
data: array
input time series
dt: float
Sample time (1/fs). It is used to calculate the Fourier frequencies,
freqs, in cycles per time unit. The default value is 0.005
NFFT: The number of data points used in each block for the FFT.
Must be even; a power 2 is most efficient. The default value is 256.
Returns:
-------
Pxx: array
power spectral destinity
freqs: array
coresponding frequencies
References:
----------
[1] http://matplotlib.sourceforge.net/api/pyplot_api.htmld
[2] IEEE Std 647-1995, IEEE Standard Specification Format Guide and Test
Procedure for Single-Axis. Laser Gyros
"""
(Pxx, freqs) = pylab.psd(data, NFFT, dt)
## Total number of samples
N = np.shape(data)[0]
time = np.arange(0,(N))
pylab.subplot(211)
pylab.plot(time,data)
pylab.subplot(212)
if plot == 1:
pylab.show()
return Pxx, freqs
def testDataVariance():
class varState:
n = 0.0
mean = 0.0
M2 = 0.0
var = 0.0
def online_variance(x,S):
S.n = S.n + 1.0
delta = x - S.mean
S.mean = S.mean + delta/S.n
if S.n > 1:
S.M2 = S.M2 + delta*(x - S.mean)
S.var = S.M2/(S.n)
return S
channels = [0,1,2,3,4,5,6,7]
varChannels = [[varState() for j in range(129)] for i in channels]
import pylab
pylab.figure()
for i in range(50):
print i
data = readFile(datfile,start=1*i,stop=1*(i+1))
for c in channels:
pylab.subplot(4,2,c+1)
px,freq = pylab.psd(data[c])
varChannels[c] = [online_variance(px[i],varChannels[c][i] ) for i in range(129)]
#fftX = pylab.fft(data[c])
#filter(lambda x: (x>100 and x<10000),fftX)
#print min(fftX),max(fftX)
#pylab.semilogx(fftX)
pylab.show()
pylab.figure()
for v in varChannels:
print sum([v[c].var for i in range(129)])/129.0
pylab.plot([v[c].var for i in range(129)])
pylab.show()
def plot_fft(self, reals, imags, time, sample_rate, fc, nfft, tfile):
m = len(reals) / nfft
dfs = []
for i in range(0, int(m)):
iqs = np.array([(re + 1j * co) for re, co in zip(reals, imags)
])[i * nfft:(i + 1) * nfft]
x = pylab.psd(iqs,
NFFT=nfft,
Fs=sample_rate / 1e6,
Fc=fc,
window=mlab.window_hanning)
total_power = self.total_power(x[0])
y = list(10 * np.log10(x[0]))
dfs.append(y)
self.total_i += 1
#print(myfile, self.total_i, total_power)
tfile.write("%s\t" % (self.total_i))
tfile.write("%s\n" % total_power)
tfile.flush()
pylab.close()
def harmonic_spectrum(a, Fs = 32000):
n_harmonics = 2
spectrum, faxis = psd(a, Fs=Fs, NFFT=500)
f_idxs = np.arange(0,len(spectrum),1)
f_idxs = f_idxs.astype(int)
max_freq = np.floor(float(faxis[-1])/n_harmonics)
max_idx = f_idxs[faxis>max_freq][0]-1
f1_idxs = np.arange(0, max_idx, 1)
f1_idxs = f1_idxs.astype(int)
f1 = faxis[f1_idxs]
f2_idxs = [ f_idxs[faxis >= 2*faxis[idx]][0] for idx in f1_idxs]
f2 = faxis[f2_idxs]
fig = plt.figure()
ax = fig.add_subplot(2,1,1)
plt.plot(f1, spectrum[f1_idxs])
plt.plot(f1, spectrum[f2_idxs])
plt.show()
def plot_fft(self, reals, imags, timea, sample_rate, fc, NFFT, myfile):
M = len(reals) / NFFT
# Open a file
text_file = open(myfile + "_energyfft.txt", "w")
for i in range(0, int(M)):
iq_samples = np.array([
(re + 1j * co) for re, co in zip(reals, imags)
])[i * NFFT:(i + 1) * NFFT]
x = pylab.psd(iq_samples,
NFFT=NFFT,
Fs=sample_rate / 1e6,
Fc=fc,
window=mlab.window_hanning)
totalpower = self.totalpower(x[0])
print myfile, i, totalpower
text_file.write("%s\n" % totalpower)
text_file.flush()
#pylab.show()
pylab.close()
text_file.close()
y1r = n1r + hr ; y2r = n2r + hr
""" Straight cross-correlation """
Ometer = np.mean( y1 * y2 )
Ometer_ana , var_Ometer_ana = Omega , ( var_n1 + Omega )*( var_n2 + Omega ) / N + Omega**2/N
""" Cross-correlation with filtering """
Y1 = stime * np.fft.fft( y1 ) ; Y2 = stime * np.fft.fft( y2 ) ; df_c12 = 1. / ( N*stime )
if N % 2 == 0 :
c12 = 2 * np.conj( Y1[ : N/2+1 ] ) * Y2[ : N/2+1 ] / (N*stime) ; f_c12 = df_c12 * np.arange( N/2+1 )
else :
c12 = 2 * np.conj( Y1[ : (N+1)/2 ] ) * Y2[ : (N+1)/2 ] / (N*stime) ; f_c12 = df_c12 * np.arange( (N+1)/2 )
Qc12 = AS.Coarsable( c12 , Offset1=f_c12[0] , Cadence1=df_c12 )
Qf_c12 = AS.Coarsable( f_c12 , Offset1=f_c12[0] , Cadence1=df_c12 )
p11l , f_p11l = pl.psd( y1l , nfft , fs , noverlap=noverlap )
p11r , f_p11r = pl.psd( y1r , nfft , fs , noverlap=noverlap )
p11 = ( p11l + p11r ) / 2 ; f_p11 = np.copy( f_p11l ) ; df_p11 = f_p11[1] - f_p11[0]
Qp11 = AS.Coarsable( p11 , Offset1=f_p11[0] , Cadence1=df_p11 )
Qf_p11 = AS.Coarsable( f_p11 , Offset1=f_p11[0] , Cadence1=df_p11 )
p22l , f_p22l = pl.psd( y2l , nfft , fs , noverlap=noverlap )
p22r , f_p22r = pl.psd( y2r , nfft , fs , noverlap=noverlap )
p22 = ( p22l + p22r ) / 2 ; f_p22 = np.copy( f_p22l ) ; df_p22 = f_p22[1] - f_p22[0]
Qp22 = AS.Coarsable( p22 , Offset1=f_p22[0] , Cadence1=df_p22 )
Qff = AS.coarsefrequency( Qf_c12 , Qf_p11 ) ; Nf = Qff.data.shape[0]
Qcc12 = Qc12.coarsegrain( Offset1=Qff.Offset1 , Cadence1=Qff.Cadence1 , N1=Qff.data.shape[0] )
Qpp11 = Qp11.coarsegrain( Offset1=Qff.Offset1 , Cadence1=Qff.Cadence1 , N1=Qff.data.shape[0] )
Qpp22 = Qp22.coarsegrain( Offset1=Qff.Offset1 , Cadence1=Qff.Cadence1 , N1=Qff.data.shape[0] )
n1 , n2 , n3 = tsdict['s1'].data , tsdict['s2'].data , tsdict['s3'].data
stime = t[1] - t[0] ; inittime = t[0] ; N = t.shape[0]
fs = 1. / stime
power_max = 3
Nsegs = 10**np.arange( power_max + 1 )
P12s = [] ; P12s_legend = [] ; C12s = [] ; C12s_legend = []
P13s = [] ; P13s_legend = [] ; C13s = [] ; C13s_legend = []
P23s = [] ; P23s_legend = [] ; C23s = [] ; C23s_legend = []
for i , Nseg in enumerate( Nsegs ) :
print "Taking %d averages to esimate spectral densities ... " % ( 2*Nseg )
nfft = int( np.round( N / Nseg ) )
noverlap = nfft / 2
P11 , f = pl.psd( n1 , nfft , fs , noverlap = noverlap )
P22 , f = pl.psd( n2 , nfft , fs , noverlap = noverlap )
P33 , f = pl.psd( n3 , nfft , fs , noverlap = noverlap )
P12 , f = pl.csd( n1 , n2 , nfft , fs , noverlap = noverlap )
P23 , f = pl.csd( n2 , n3 , nfft , fs , noverlap = noverlap )
P13 , f = pl.csd( n1 , n3 , nfft , fs , noverlap = noverlap )
C12 = np.abs( P12 )**2 / ( P11*P22 )
C23 = np.abs( P23 )**2 / ( P22*P33 )
C13 = np.abs( P13 )**2 / ( P11*P33 )
for k in range( C12.shape[0] ) :
if C12[k] < 0 :
print 'C12[%d] < 0' % k
P12s += [ f , np.abs( P12 ) ] ; C12s += [ f , C12 ] ; C12s_legend += [ '%d' % Nseg ]
P23s += [ f , np.abs( P23 ) ] ; C23s += [ f , C23 ] ; C23s_legend += [ '%d' % Nseg ]
Count = 2000
Rate = 10000
Options = UL.CONVERTDATA
ADData = Numeric.zeros((Count,), Numeric.Int16)
ActualRate = UL.cbAInScan(BoardNum, LowChan, HighChan, Count,
Rate, Gain, ADData, Options)
time = Numeric.arange( ADData.shape[0] )*1.0/ActualRate
# convert to Volts
data_in_volts = [ UL.cbToEngUnits(BoardNum, Gain, y) for y in ADData]
data_in_volts = Numeric.array(data_in_volts) # convert to Numeric array
pxx, freqs = pylab.psd( data_in_volts, Fs=ActualRate )
decibels = 10*Numeric.log10(pxx)
pylab.subplot(2,1,1)
pylab.plot(time[100:200],data_in_volts[100:200],'o-') # plot a few samples
pylab.xlabel('time (sec)')
pylab.ylabel('Volts')
pylab.subplot(2,1,2)
pylab.plot(freqs, decibels, 'o-')
pylab.xlabel('frequency')
pylab.ylabel('Power (decibels)')
pylab.savefig('example4.png',dpi=72)
pylab.show()
# <markdowncell>
# For this example, I've turned up the frequency on the function generator