FIR Filter Example

!SimpleWave.ipynb

fir.py

import numpy as np
import simpleaudio as sa
import time

# Set up audio params
sample_rate = 44100
sound_length = 5 #seconds
t = np.linspace(0, sound_length, sound_length * sample_rate, False)

# Define signals
wave1_freq = 4000
wave1_amplitude = 2
wave1_phi = 0
wave1 = wave1_amplitude * np.sin(wave1_freq * t * 2 * np.pi + wave1_phi)

wave2_freq = 1600
wave2_amplitude = 0.8
wave2_phi = 0
wave2 = wave2_amplitude * np.sin(wave2_freq * t * 2 * np.pi + wave2_phi)

wave3_freq = 600
wave3_amplitude = 1.2
wave3_phi = 0.4
wave3 = wave3_amplitude * np.sin(wave3_freq * t * 2 * np.pi + wave3_phi)

# Combine signals
signal = np.add(wave1, wave2)
signal = np.add(signal, wave3)

taps = np.array([
  0.0003745900908163193, \
  0.001035951933453526, \
  0.0007325310976027528, \
  0.0012734899113014343, \
  0.001505827537138896, \
  0.001906701284701609, \
  0.002255193914554153, \
  0.002622053674575616, \
  0.0029498890263962266, \
  0.0032316494614751663, \
  0.0034367455949670237, \
  0.003543326323203393, \
  0.0035271808853288783, \
  0.003366493641359242, \
  0.0030440547958260227, \
  0.002546845932748022, \
  0.0018699255183142716, \
  0.0010145993691660009, \
  -0.000007822740186522711, \
  -0.0011772398017138564, \
  -0.0024623894663077057, \
  -0.0038224245149365193, \
  -0.005207993967976202, \
  -0.006559950494834579, \
  -0.007813025767998694, \
  -0.00889630342344623, \
  -0.009737673508070597, \
  -0.010263527022136008, \
  -0.010403904283509603, \
  -0.010094690943920976, \
  -0.009281193138939584, \
  -0.007920352308374777, \
  -0.005982648536411453, \
  -0.0034573396113584203, \
  -0.0003501983730495297, \
  0.0033130673334052624, \
  0.007486572786566192, \
  0.012105787794150783, \
  0.017087762369887797, \
  0.022333435670723732, \
  0.027729793775114597, \
  0.0331544017002729, \
  0.03847753819629622, \
  0.04356671732492255, \
  0.04829283271615901, \
  0.0525316528144209, \
  0.05616977310170035, \
  0.059109496837266275, \
  0.061269060239080915, \
  0.06258934720612876, \
  0.06303403098445609, \
  0.06258934720612876, \
  0.061269060239080915, \
  0.059109496837266275, \
  0.05616977310170035, \
  0.0525316528144209, \
  0.04829283271615901, \
  0.04356671732492255, \
  0.03847753819629622, \
  0.0331544017002729, \
  0.027729793775114597, \
  0.022333435670723732, \
  0.017087762369887797, \
  0.012105787794150783, \
  0.007486572786566192, \
  0.0033130673334052624, \
  -0.0003501983730495297, \
  -0.0034573396113584203, \
  -0.005982648536411453, \
  -0.007920352308374777, \
  -0.009281193138939584, \
  -0.010094690943920976, \
  -0.010403904283509603, \
  -0.010263527022136008, \
  -0.009737673508070597, \
  -0.00889630342344623, \
  -0.007813025767998694, \
  -0.006559950494834579, \
  -0.005207993967976202, \
  -0.0038224245149365193, \
  -0.0024623894663077057, \
  -0.0011772398017138564, \
  -0.000007822740186522711, \
  0.0010145993691660009, \
  0.0018699255183142716, \
  0.002546845932748022, \
  0.0030440547958260227, \
  0.003366493641359242, \
  0.0035271808853288783, \
  0.003543326323203393, \
  0.0034367455949670237, \
  0.0032316494614751663, \
  0.0029498890263962266, \
  0.002622053674575616, \
  0.002255193914554153, \
  0.001906701284701609, \
  0.001505827537138896, \
  0.0012734899113014343, \
  0.0007325310976027528, \
  0.001035951933453526, \
  0.0003745900908163193])

# Execute the filter
output = np.zeros(signal.size - taps.size)
for i in range(output.size):
    output[i] = np.inner(taps, signal[taps.size + i:i:-1])


# Normalize audio level to 16 bit int for simpleaudio
signal *= 32767 / np.max(np.abs(signal))
signal = signal.astype(np.int16)

# Start playback then wait for finish
play_obj = sa.play_buffer(signal, 1, 2, sample_rate)
play_obj.wait_done()

# # Now wait one second
time.sleep(1)

# Normalize audio level to 16 bit int for simpleaudio
output *= 32767 / np.max(np.abs(output))
output = output.astype(np.int16)

# print(signal[:300])
# print(output[:300])

# Start playback then wait for finish
play_obj = sa.play_buffer(output, 1, 2, sample_rate)
play_obj.wait_done()