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Need help converting matrix of i2s values to sound

Latest activity Commented on by Walter Roberson
on 10 Sep 2019
Hi, I have a 32768x1 matrix in matlab, ( 32768 samples of a i2s microphone that i captured from an FPGA, values are currently in decimal but they represent a 18 bit vector of the i2s PCM sample from the microphone). I need to convert this matrix to sound to test the microphone, but i need help to get it done.
Thanks to everybody.

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I am need this help, as i too have captured the i2s microphone data, but dont know who can i playback the same to verify my recording.
Thnaks in advance for any help.
Is it linear PCM, LPCM ? If so then divide by 2^18, then multiply by 2 and then subtract 1 to get data suitable for playing.
(or just divide by 2^17 and subtract 1)
By the way, does the fi hint that the data is stored as FixedPoint instead of as int32 or uint32 ?

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1 Answer

Answer by Ted Shultz
on 10 Sep 2019

You could try to use the audioplayer function. You would need to scale your data, and know the sample frequency.
You code may look something like this:
Fs = 48000; % Hz (use your value here)
Y =2*( fi-min(fi)) / (max(fi)-min(fi))-1; % scale data
player = audioplayer(Y,Fs); %make audio player

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