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Accomodate the zero baseline, reduce distortion

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Changed the array type to allow I2S signed values. Eliminated the baseline in the ``math.sin`` portion of the code. Updated the calculated value range to represent a maximum value of 32767 rather than 32678 to avoid distortion caused by value wrap-around.
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Cedar Grove Maker Studios 2018-08-06 18:10:02 -07:00 committed by GitHub
parent 6fe6d640b2
commit 0a2b0d3d51
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1 changed files with 2 additions and 2 deletions
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Adafruit_UDA1334A/CircuitPython_I2S_Tone.py
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@ -8,9 +8,9 @@ import audiobusio
tone_volume = 0.1 # Increase this to increase the volume of the tone. tone_volume = 0.1 # Increase this to increase the volume of the tone.
frequency = 440 # Set this to the Hz of the tone you want to generate. frequency = 440 # Set this to the Hz of the tone you want to generate.
length = 8000 // frequency length = 8000 // frequency
sine_wave = array.array("H", [0] * length) sine_wave = array.array("h", [0] * length)
for i in range(length): for i in range(length):
sine_wave[i] = int((1 + math.sin(math.pi * 2 * i / 18)) * tone_volume * (2 ** 15)) sine_wave[i] = int((math.sin(math.pi * 2 * i / length)) * tone_volume * (2 ** 15 -1))
# For Feather M0 Express, ItsyBitsy M0 Express, Metro M0 Express # For Feather M0 Express, ItsyBitsy M0 Express, Metro M0 Express
audio = audiobusio.I2SOut(board.D1, board.D0, board.D9) audio = audiobusio.I2SOut(board.D1, board.D0, board.D9)