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#
# Copyright (c) 2019 Analog Devices Inc.
#
# (see http://www.github.com/analogdevicesinc/libm2k).
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU Lesser General Public License as published by
# the Free Software Foundation, either version 2.1 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU Lesser General Public License for more details.
#
# You should have received a copy of the GNU Lesser General Public License
# along with this program. If not, see <http://www.gnu.org/licenses/>.
#
# This example assumes the following connections:
# W1 -> 100-ohm resistor in series with speaker
# W2 -> open
# 2+ -> Microphone
# GND -> 1-
# GND -> 2-
#
# The application will record a few seconds of audio on scope channel 2, reverse the order of the samples,
# Apply some filtering tricks to remove large DC offsets, then play back. Playback is at 75% of record speed just due
# to available sample rates.
import libm2k
import matplotlib.pyplot as plt
import time
import numpy as np
ctx = libm2k.m2kOpen()
if ctx is None:
print("Connection Error: No ADALM2000 device available/connected to your PC.")
exit(1)
ain = ctx.getAnalogIn()
aout = ctx.getAnalogOut()
trig = ain.getTrigger()
ps = ctx.getPowerSupply()
# Prevent bad initial config for ADC and DAC
ain.reset()
aout.reset()
ps.reset()
ctx.calibrateADC()
ctx.calibrateDAC()
ps.enableChannel(0, True) # Consider using for microphone power,
ps.pushChannel(0, 4.0) # unfortunately DC blocking cap takes forever to charge
print("waiting 1 second for mic to settle...")
time.sleep(1.0)
ain.enableChannel(0, True)
ain.enableChannel(1, True)
ain.setSampleRate(10000)
ain.setRange(1, -1, 1)
print("ain sample rate: " + str(ain.getSampleRate()))
print("ain range: " + str(ain.getRangeLimits(1)))
input("\nPress key to record")
print("Recording...")
time.sleep(0.1)
startime = time.time()
bufflen = 2 ** 16
data = ain.getSamples(bufflen)
captime = time.time() - startime
print("recorded time: " + str(captime))
print("playing back flipped...")
aout.setSampleRate(0, 7500)
aout.setSampleRate(1, 7500)
aout.enableChannel(0, True)
aout.enableChannel(1, True)
print("aout sample rate: " + str(aout.getSampleRate()))
audio = data[1]
gain = 100.0
dc = np.convolve(audio, (np.ones(64) / 64.0), mode='same') # Calculate running DC average
audio = audio - dc
audio[0:100] = [0] * 100 # get rid of edge effect
normal_audio = audio
audio = np.flip(audio) # Here's where the flip happens!!
audio = audio * gain # add some gain
# Push data
buffer = [audio, audio]
aout.setCyclic(True)
aout.push(buffer)
# Plot audio data
plt.plot(audio, label="flipped audio")
plt.plot(np.array(normal_audio * gain), label="normal audio")
plt.legend()
plt.show()
time.sleep(5)
libm2k.contextClose(ctx)
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