def report_carrier(bufs, begin):
x = np.concatenate(tuple(bufs)[-CARRIER_THRESHOLD:-1])
Hc = sigproc.exp_iwt(-config.Fc, len(x))
Zc = np.dot(Hc, x) / (0.5*len(x))
amp = abs(Zc)
log.info('Carrier detected at ~%.1f ms @ %.1f kHz:'
' coherence=%.3f%%, amplitude=%.3f',
begin * config.Tsym * 1e3 / config.Nsym, config.Fc / 1e3,
np.abs(sigproc.coherence(x, config.Fc)) * 100, amp)
return amp
def find_start(buf, length):
Hc = sigproc.exp_iwt(config.Fc, len(buf))
P = np.abs(Hc.conj() * buf) ** 2
cumsumP = P.cumsum()
return np.argmax(cumsumP[length:] - cumsumP[:-length])
