Started code for DSP final project

6th-Semester-Spring-2024/DSP/Labs/FinalProject/addnoisex.m

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+%*********************ADD FROM NOISEX DATABASE *******************
+% function [t] = addnoisex(sclean,snoise,snr,outfile)
+% add noise from a file in noisex database to signal
+% t - noisy signal - written in output wave file 
+% sclean - clean signal - read either as dat or wave file
+% snoise - name of noise file, example: white for 'white.dat'
+%       - read in as dat or wave file
+% snr - desired snr in db
+% outfile - The output file is written as a wav file
+% Example [t]=addnoisex('s.wav','street.dat',30,'s_noisy_snr30.wav')
+%****************************************************
+%
+function [t] = addnoisex(sclean,snoise,snr,outfile)
+
+% Read input clean sognal and noise file
+[s]=load_or_audioread(sclean);
+[nfile]=load_or_audioread(snoise);
+
+% Record length of speech signal and noise file
+nspeech=length(s);
+nns=length(nfile);
+
+% Randomly select starting sample of noise file and
+% read same number of samples as speech signal
+start=ceil(rand()*(nns-nspeech+1)); 
+finish=start+nspeech-1;
+noise=nfile(start:finish);
+
+% Calculate noise power and signal power
+powernoise=norm(noise,2);
+powersignal=norm(s,2);
+
+% Adjust noise level for desired SNR
+u=10^(snr/20);
+powerdesirednoise=powersignal/u;
+ratio=powerdesirednoise/powernoise;
+noise=ratio*noise;
+
+% Add the noise
+t=s+noise;
+
+% Display snr
+signaltonoise=20.0*log10(powersignal/norm(noise));
+
+% Write as wave file
+audiowrite(outfile,t,8000,'BitsPerSample',16);