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import SoapySDR
import numpy as np
from scipy.signal import blackmanharris
from stabilizer import InductionHeater
fs = 5e6
base_freq = 1086e6
threshold = 0.4
target_freq = 1088.3e6
k = 200e-6
def parabolic(f, x):
xv = 1/2. * (f[x-1] - f[x+1]) / (f[x-1] - 2 * f[x] + f[x+1]) + x
yv = f[x] - 1/4. * (f[x-1] - f[x+1]) * (xv - x)
return (xv, yv)
def fmt_range(x, m):
pos = int(round(x*80/m))
return " "*pos + "*"
def main():
induction = InductionHeater("/dev/ttyUSB0", 430e3, 445e3)
induction.start()
try:
sdr = SoapySDR.Device()
samples = np.array([0]*4096, np.complex64)
sdr.setSampleRate(SoapySDR.SOAPY_SDR_RX, 0, fs)
sdr.setFrequency(SoapySDR.SOAPY_SDR_RX, 0, base_freq)
rxStream = sdr.setupStream(SoapySDR.SOAPY_SDR_RX, SoapySDR.SOAPY_SDR_CF32)
sdr.activateStream(rxStream)
decimation = 0
try:
while True:
sr = sdr.readStream(rxStream, [samples], len(samples))
if sr.ret != len(samples):
print("!")
continue
freqs = np.abs(np.fft.fft(samples*blackmanharris(len(samples)))[0:len(samples)//2])
for i in range(len(freqs)//100):
freqs[i] = 0
freqs[-i] = 0
# https://gist.github.com/endolith/255291
i = np.argmax(freqs)
true_i = parabolic(freqs, i)[0]
freq = 0.5 * fs * true_i / len(freqs)
amplitude = freqs[i]
if amplitude > threshold:
actual_freq = base_freq + freq
print("{:8.3f} {:6.2f} {}".format(actual_freq/1e6, amplitude, fmt_range(freq, fs/2)))
induction_amt = (actual_freq - target_freq)*k
else:
print("<no signal>", amplitude)
induction_amt = 0.0
decimation += 1
if decimation == 30:
induction.set(induction_amt)
decimation = 0
finally:
sdr.deactivateStream(rxStream)
sdr.closeStream(rxStream)
finally:
induction.stop()
if __name__ == "__main__":
main()