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recv: log SNR during demodulation

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This commit is contained in:
Roman Zeyde
2015-02-04 18:08:32 +02:00
parent 1c13671a4c
commit b39334bfe8
1 changed files with 27 additions and 14 deletions
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41
amodem/recv.py
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@@ -92,14 +92,9 @@ class Receiver(object):
'$F_c = {0} Hz$'.format(freq), index=i)
assert error_rate == 0, error_rate
def _demodulate(self, sampler, symbols):
def _bitstream(self, symbols, error_handler):
streams = []
symbol_list = []
errors = {}
def error_handler(received, decoded, freq):
errors.setdefault(freq, []).append(received / decoded)
generators = common.split(symbols, n=len(self.omegas))
for freq, S in zip(self.frequencies, generators):
equalized = []
@@ -108,15 +103,27 @@ class Receiver(object):
freq_handler = functools.partial(error_handler, freq=freq)
bits = self.modem.decode(S, freq_handler) # list of bit tuples
streams.append(bits) # stream per frequency
streams.append(bits) # bit stream per frequency
return common.izip(streams), symbol_list
def _demodulate(self, sampler, symbols):
symbol_list = []
errors = {}
noise = {}
def _handler(received, decoded, freq):
errors.setdefault(freq, []).append(received / decoded)
noise.setdefault(freq, []).append(received - decoded)
stream, symbol_list = self._bitstream(symbols, _handler)
self.stats['symbol_list'] = symbol_list
self.stats['rx_bits'] = 0
self.stats['rx_start'] = time.time()
log.info('Starting demodulation')
for i, block in enumerate(common.izip(streams), 1):
for bits in block:
for i, block_of_bits in enumerate(stream, 1):
for bits in block_of_bits:
self.stats['rx_bits'] = self.stats['rx_bits'] + len(bits)
yield bits
@@ -124,11 +131,7 @@ class Receiver(object):
self._update_sampler(errors, sampler)
if i % self.iters_per_report == 0:
log.debug(
'Got %10.3f kB, drift: %+5.2f ppm',
self.stats['rx_bits'] / 8e3,
(1.0 - sampler.freq) * 1e6
)
self._report_progress(noise, sampler)
def _update_sampler(self, errors, sampler):
err = np.array([e for v in errors.values() for e in v])
@@ -138,6 +141,16 @@ class Receiver(object):
sampler.freq -= 0.01 * err * self.Tsym
sampler.offset -= err
def _report_progress(self, noise, sampler):
e = np.array([e for v in noise.values() for e in v])
noise.clear()
log.debug(
'Got %10.3f kB, SNR: %5.2f dB, drift: %+5.2f ppm',
self.stats['rx_bits'] / 8e3,
-10 * np.log10(np.mean(np.abs(e) ** 2)),
(1.0 - sampler.freq) * 1e6
)
def run(self, sampler, gain, output):
symbols = dsp.Demux(sampler, omegas=self.omegas, Nsym=self.Nsym)
self._prefix(symbols, gain=gain)