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optimize QAM decoder

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Roman Zeyde
2014-08-10 09:43:51 +03:00
parent 9358f7ba39
commit ecae434282
1 changed files with 20 additions and 6 deletions
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26
amodem/sigproc.py
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@@ -49,18 +49,32 @@ class QAM(object):
self.symbols = symbols
self.bits_per_symbol = bits_per_symbol
reals = np.array(list(sorted(set(symbols.real))))
imags = np.array(list(sorted(set(symbols.imag))))
self.real_factor = 2.0 / np.mean(np.diff(reals))
self.imag_factor = 2.0 / np.mean(np.diff(imags))
self.symbols_map = {}
for S in symbols:
real_index = round(S.real * self.real_factor)
imag_index = round(S.imag * self.imag_factor)
self.symbols_map[real_index, imag_index] = (S, self._dec[S])
def encode(self, bits):
for _, bits_tuple in common.iterate(bits, self.bits_per_symbol, tuple):
yield self._enc[bits_tuple]
def decode(self, symbols, error_handler=None):
for s in symbols:
index = np.argmin(np.abs(s - self.symbols))
S = self.symbols[index]
real_factor = self.real_factor
imag_factor = self.imag_factor
symbols_map = self.symbols_map
for S in symbols:
real_index = round(S.real * real_factor)
imag_index = round(S.imag * imag_factor)
decoded_symbol, bits = symbols_map[real_index, imag_index]
if error_handler:
error_handler(received=s, decoded=S)
yield self._dec[S]
error_handler(received=S, decoded=decoded_symbol)
yield bits
class Demux(object):
def __init__(self, src, freqs):