def __transmitSignal(samplingError, offset, snr, attenuation, freqErr, phaseErr):
modulator = Modulator(__CARRIER_FREQ, __SYMBOL_LENGTH_IN_BITS, __FI, __SAMPLING_RATE)
demodulator = Demodulator(__CARRIER_FREQ, __SYMBOL_LENGTH_IN_BITS, __FI, __SAMPLING_RATE)
channel = RadioChannel(__SAMPLING_RATE)
frameSync = FrameSynchronization(modulator.modulate(__HEADER), modulator.modulate(__END_HEADER),
__SYMBOL_LENGTH_IN_BITS, __SAMPLING_RATE)
timeRecover = TimingRecovery(__SYMBOL_LENGTH_IN_BITS)
modulationStart = time.time()
modulatedSignal = modulator.modulate(__FRAME)
assert(time.time() - modulationStart < 1 / 25)
transmittedSignal = channel.transmit(modulatedSignal, signalOffset=offset, adcSamplingErr=samplingError, snr=snr,
channelAttenuation=attenuation, freqErr=freqErr, phaseErr=phaseErr)
synchronizationStart = time.time()
dataPosition = frameSync.synchronizeStartHeader(transmittedSignal)
dataEndPosition = frameSync.synchronizeStopHeader(transmittedSignal[dataPosition:])
transmittedSignal = frameSync.correctFreqAndPhase(transmittedSignal[dataPosition:dataPosition + dataEndPosition])
transmittedSignal = timeRecover.synchronizeTiming(transmittedSignal)
demodulatedBits = demodulator.demodulate(transmittedSignal)
assert (time.time() - synchronizationStart < 1 / 25)
return demodulatedBits
def __transmitSignalWithTimingSynchronization(samplingErr):
modulator = Modulator(__CARRIER_FREQ, __SYMBOL_LENGTH_IN_BITS, __FI,
__SAMPLING_RATE)
demodulator = Demodulator(__CARRIER_FREQ, __SYMBOL_LENGTH_IN_BITS, __FI,
__SAMPLING_RATE)
timeRecover = TimingRecovery(__SYMBOL_LENGTH_IN_BITS)
channel = RadioChannel(__SAMPLING_RATE)
signal = modulator.modulate(__BITS)
transmittedSignal = channel.transmit(signal,
adcSamplingErr=samplingErr,
snr=10)
transmittedSignal = timeRecover.synchronizeTiming(transmittedSignal)
demodulatedBits = demodulator.demodulate(transmittedSignal)
return demodulatedBits
def __transmitSignalWithFrameSynchronizationAndSamplingError(samplingError, offset, snr=None):
modulator = Modulator(__CARRIER_FREQ, __SYMBOL_LENGTH_IN_BITS, __SAMPLING_RATE)
demodulator = Demodulator(__CARRIER_FREQ, __SYMBOL_LENGTH_IN_BITS, __SAMPLING_RATE)
channel = RadioChannel(__SAMPLING_RATE)
frameSync = FrameSynchronization(modulator.modulate(__START_HEADER), modulator.modulate(__END_HEADER),
__SYMBOL_LENGTH_IN_BITS, __SAMPLING_RATE)
timeRecover = TimingRecovery(__SYMBOL_LENGTH_IN_BITS)
modulatedSignal = modulator.modulate(__FRAME)
transmittedSignal = channel.transmit(modulatedSignal, signalOffset=offset, adcSamplingErr=samplingError, snr=snr)
dataPosition = frameSync.synchronizeStartHeader(transmittedSignal)
dataEndPosition = frameSync.synchronizeStopHeader(transmittedSignal)
transmittedSignal = transmittedSignal[dataPosition:dataEndPosition]
transmittedSignal = timeRecover.synchronizeTiming(transmittedSignal)
demodulatedBits = demodulator.demodulate(transmittedSignal)
return demodulatedBits
class Receiver:
def __init__(self, sampleRate, carrierFreq, symbolLength, frameSize):
self.sampleRate = sampleRate
self.carrierFreq = carrierFreq
self.symbolLength = symbolLength
self.frameSizeInBits = frameSize * 8 / 2
self.headerStart = [
0, 0, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1,
1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 0, 0, 0, 0, 1, 1, 1, 1,
1, 1, 0, 0, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 0, 0
]
self.headerEnd = [
1, 1, 0, 0, 0, 0, 0, 1, 1, 0, 0, 1, 1, 1, 0, 0, 1, 1, 1, 0, 1, 0,
0, 1, 1, 1, 0, 0, 0, 0, 0, 1, 1, 0, 0, 1, 1, 1, 1, 1, 0, 1, 1, 0,
0, 1, 0, 0, 0, 0, 1, 1, 0, 1, 1, 0, 1, 0, 1, 1, 0, 0, 1, 1, 0, 1,
1, 0, 0, 1, 0, 0, 0, 0, 1, 1
]
self.rtl = RtlSdr()
self.rtl.sample_rate = self.sampleRate
self.rtl.center_freq = self.carrierFreq
self.demodulator = Demodulator(self.carrierFreq, self.symbolLength,
self.sampleRate)
self.modulator = Modulator(self.carrierFreq, self.symbolLength,
self.sampleRate)
self.frameSync = FrameSynchronization(
self.modulator.modulate(self.headerStart),
self.modulator.modulate(self.headerEnd), self.symbolLength,
self.sampleRate)
self.timeRecover = TimingRecovery(self.symbolLength)
self.rtlSamples = Queue()
self.frames = Queue()
self.previousData = Queue(1)
self.previousData.put([0])
self.data = Queue()
self.threads = []
self.threads.append(threading.Thread(target=self.receive))
self.threads.append(threading.Thread(target=self.findFrame))
self.threads.append(threading.Thread(target=self.processData))
self.threads.append(threading.Thread(target=self.playSound))
for th in self.threads:
th.start()
def receive(self):
def rtl_callback(samples, rtlsdr_obj):
self.rtlSamples.put(samples)
self.rtl.read_samples_async(rtl_callback, self.sampleRate / 10)
def findFrame(self):
currentData = self.rtlSamples.get()
prevData = self.previousData.get()
data = np.append(prevData, currentData)
dataPosition = self.frameSync.synchronizeStartHeader(data)
dataEndPosition = self.frameSync.synchronizeStopHeader(
data[dataPosition:])
if abs(dataEndPosition -
self.frameSizeInBits) <= self.frameSizeInBits / 10:
print("Frame found. Size = " + str(dataEndPosition))
self.previousData.put(data[dataPosition + dataEndPosition:])
self.frames.put(data[dataPosition:dataPosition + dataEndPosition])
else:
self.previousData.put(currentData)
def processData(self):
data = self.frames.get()
data = self.frameSync.correctFreqAndPhase(data)
data = self.timeRecover.synchronizeTiming(data)
data = self.demodulator.demodulate(data)
self.data.put(data)
def playSound(self):
dataToPlay = self.data.get()
#TODO: write func
return