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import numpy as np
from scipy import signal, optimize
import sys
import matplotlib.pyplot as plt
import datetime
import logging
def phase_align(sig, ref_sig):
"""Do phase alignment for sig relative to the reference signal
ref_sig.
Returns the aligned signal"""
angle_diff = (np.angle(sig) - np.angle(ref_sig)) % (2. * np.pi)
real_diffs = np.cos(angle_diff)
imag_diffs = np.sin(angle_diff)
if logging.getLogger().getEffectiveLevel() == logging.DEBUG:
dt = datetime.datetime.now().isoformat()
fig_path = "/tmp/" + dt + "_phase_align.pdf"
plt.subplot(511)
plt.hist(angle_diff, bins=60, label="Angle Diff")
plt.xlabel("Angle")
plt.ylabel("Count")
plt.legend(loc=4)
plt.subplot(512)
plt.hist(real_diffs, bins=60, label="Real Diff")
plt.xlabel("Real Part")
plt.ylabel("Count")
plt.legend(loc=4)
plt.subplot(513)
plt.hist(imag_diffs, bins=60, label="Imaginary Diff")
plt.xlabel("Imaginary Part")
plt.ylabel("Count")
plt.legend(loc=4)
plt.subplot(514)
plt.plot(np.angle(ref_sig[:128]), label="ref_sig")
plt.plot(np.angle(sig[:128]), label="sig")
plt.xlabel("Angle")
plt.ylabel("Sample")
plt.legend(loc=4)
real_diff = np.median(real_diffs)
imag_diff = np.median(imag_diffs)
angle = np.angle(real_diff + 1j * imag_diff)
logging.debug(
"Compensating phase by {} rad, {} degree. real median {}, imag median {}".format(
angle, angle*180./np.pi, real_diff, imag_diff
))
sig = sig * np.exp(1j * -angle)
if logging.getLogger().getEffectiveLevel() == logging.DEBUG:
plt.subplot(515)
plt.plot(np.angle(ref_sig[:128]), label="ref_sig")
plt.plot(np.angle(sig[:128]), label="sig")
plt.xlabel("Angle")
plt.ylabel("Sample")
plt.legend(loc=4)
plt.tight_layout()
plt.savefig(fig_path)
plt.clf()
return sig
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