# SNR of sigma delta modulator

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#### avinash

##### Full Member level 3
snr sigma delta matlab code

i have the simulated bitstream output of 16-bit sigma delta modulator.nor i want to check the SNR of the same by passing the bitstreams through a ideal low pass filter in matlab.can anyone tell me the commands of the matlab toi measure the SNR.

calculatesnr

make a digital down sampling filter first.
Why not use cooledit? It's a good software to analysis voice data.

sigma delta matlab

FFT
PSD

snr for sigma delta bitstream

dear sunking,
i know that FFT has to be performed.but please tell me the commands used in matlab.

### avinash

Points: 2
Assume that you the get the bitstream and read it to Array A in matlab.
get the number of data in A is N*f, which means that to total number is N times of the signal freq.
B=fft(A(1:N*f))
M=max(B);
N=sum(M)
SNR=db(M/(N-M))

### avinash

Points: 2
sunking said:
Assume that you the get the bitstream and read it to Array A in matlab.
get the number of data in A is N*f, which means that to total number is N times of the signal freq.
B=fft(A(1:N*f))
M=max(B);
N=sum(M)
SNR=db(M/(N-M))

thanks a lot sunking,
i will definetely try these commands in matlab.can you please tell me the brief description of these commands used by you.
moreover my bitstream file consists of table in which two columns are there.left column contains the time from zero to 4 times the period of signal having the incremental change at every time corresponding to oversampling freq.and right column consists of bit corresponding to every incremental oversampling time.i hope you understood the above explanation.now my question is does this file match the requirement of array A that was mentioned by you,or i have to modify the bitstream file.thanks in advance.

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