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https://github.com/romanz/amodem.git
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82 lines
2.0 KiB
Python
82 lines
2.0 KiB
Python
import subprocess as sp
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import numpy as np
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import os
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import time
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import signal
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import logging
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import itertools
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logging.basicConfig(level=0, format='%(message)s')
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log = logging.getLogger(__name__)
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import ecc
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import sigproc
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from common import *
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dev_null = open('/dev/null')
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def play(fd):
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args = ['aplay', fd.name, '-q', '-f', 'S16_LE', '-c', '1', '-r', str(int(Fs))]
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ret = sp.call(args=args)
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assert ret == 0
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def record(fname):
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args = ['arecord', fname, '-q', '-f', 'S16_LE', '-c', '1', '-r', str(int(Fs))]
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p = sp.Popen(args=args)
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p.stop = lambda: os.kill(r.pid, signal.SIGINT)
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return p
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class Symbol(object):
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t = np.arange(0, Nsym) * Ts
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carrier = [ np.exp(2j * np.pi * F * t) for F in frequencies ]
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sym = Symbol()
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data = open('data.send', 'r').read()
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def start(sig, c):
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sig.send(c*0, n=100)
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sig.send(c*1, n=300)
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sig.send(c*0, n=100)
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def train(sig, c):
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for i in range(20):
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sig.send(c*1, n=10)
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sig.send(c*0, n=10)
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sig.send(c*0, n=100)
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def modulate(sig, bits):
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symbols_iter = sigproc.modulator.encode(list(bits))
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symbols_iter = itertools.chain(symbols_iter, itertools.repeat(0))
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carriers = np.array(sym.carrier) / len(sym.carrier)
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while True:
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symbols = itertools.islice(symbols_iter, len(sym.carrier))
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symbols = np.array(list(symbols))
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sig.send(np.dot(symbols, carriers))
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if all(symbols == 0):
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break
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if __name__ == '__main__':
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bps = baud * sigproc.modulator.bits_per_symbol * len(sym.carrier)
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log.info('Running MODEM @ {:.1f} kbps'.format(bps / 1e3))
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with open('tx.int16', 'wb') as fd:
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sig = Signal(fd)
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start(sig, sym.carrier[carrier_index])
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for c in sym.carrier:
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train(sig, c)
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bits = to_bits(ecc.encode(data))
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modulate(sig, bits)
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r = record('rx.int16')
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start = time.time()
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p = play(fd)
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log.debug('Took %.2f seconds', time.time() - start)
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time.sleep(0.1)
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r.stop()
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