def open(self, fname):
"""Open data with appropriate baseband reader"""
if self.dtype == 'vdif':
self.fh = vdif.open(fname, mode='rs', sample_rate=self.sample_rate)
if self.dtype == 'mark4':
self.fh = mark4.open(fname, mode='rs', decade=2010, ntrack=self.ntrack,
sample_rate=self.sample_rate, thread_ids=self.thread_ids)
if self.dtype == 'mark5b':
self.fh = mark5b.open(fname, mode='rs', nchan=self.nIF, ref_mjd=57000,
sample_rate=self.sample_rate, thread_ids=self.thread_ids)
def __init__(self,fn,t_gp): self.t_gp = t_gp fh = mark5b.open(fn, mode='rs', nchan=16, sample_rate=sample_rate, thread_ids=thread_ids, ref_mjd=57000) offset_gp = ((t_gp - fh.tell(unit='time')).to(u.s).value * fh.frames_per_second * fh.samples_per_frame) fh.seek(int(offset_gp) - size // 2) self.d_dispersed = fh.read(size) #start_time = time.time() #print start_time self.process_data() #print time.time()-start_time self.process_output()
def open(self, fname):
"""Open data with appropriate baseband reader"""
if self.dtype == 'vdif':
self.fh = vdif.open(fname, mode='rs', sample_rate=self.sample_rate)
if self.dtype == 'mark4':
self.fh = mark4.open(fname,
mode='rs',
decade=2010,
ntrack=self.ntrack,
sample_rate=self.sample_rate,
thread_ids=self.thread_ids)
if self.dtype == 'mark5b':
self.fh = mark5b.open(fname,
mode='rs',
nchan=self.nIF,
ref_mjd=57000,
sample_rate=self.sample_rate,
thread_ids=self.thread_ids)
return d * (1./f**2 - 1./fref**2)
else:
dang = (d * f * (1./fref-1./f)**2) * u.cycle
if kind == 'phase':
return dang
elif kind == 'complex':
return np.exp(dang.to(u.rad).value * 1j)
raise ValueError("kind not one of 'delay', 'phase', or 'complex'")
dm = DispersionMeasure(dm)
if __name__ == '__main__':
fh = mark5b.open(fn, mode='rs', nchan=16,
sample_rate=sample_rate, thread_ids=thread_ids, ref_mjd=57000)
offset_gp = ((t_gp - fh.tell(unit='time')).to(u.s).value *
fh.frames_per_second * fh.samples_per_frame)
fh.seek(int(offset_gp) - size // 2)
d = fh.read(size)
ft = np.fft.rfft(d, axis=0)
# Second half of IFs have Fedge at top, need to subtract frequencies,
# and not conjugate coherent phases
f = fedge + np.fft.rfftfreq(d.shape[0], dt1)[:, np.newaxis]
f[:,8:] = fedge[8:] - np.fft.rfftfreq(d.shape[0], dt1)[:, np.newaxis]
ft[:,:8] *= dm(f[:,:8], fref, kind='complex').conj()
ft[:,8:] *= dm(f[:,8:], fref, kind='complex')
d = np.fft.irfft(ft, axis=0)
# Channelize the data
dchan = np.fft.rfft(d.reshape(-1, 2*nchan, 16), axis=1)
dang = (d * f * (1. / fref - 1. / f)**2) * u.cycle
if kind == 'phase':
return dang
elif kind == 'complex':
return np.exp(dang.to(u.rad).value * 1j)
raise ValueError("kind not one of 'delay', 'phase', or 'complex'")
dm = DispersionMeasure(dm)
if __name__ == '__main__':
fh = mark5b.open(fn,
mode='rs',
nchan=16,
sample_rate=sample_rate,
thread_ids=thread_ids,
ref_mjd=57000)
for i in range(745):
print('step %s of %s' % (i, 745))
fh.seek(i * step)
t0 = fh.tell("time")
print(t0.isot)
d = pyfftw.empty_aligned((size, 16), dtype='float32')
d[:] = fh.read(size)
print('First FFT')
ft = fft_object_a(d)
#d = fh.read(size)