www.pudn.com > PSK.zip > my_speech.m

function my_speech(M, type_of_mod, fc, fs) 
 
% here i am going to test my speech through various QAM, and PSK mod-demod 
% techniques 
 
%santosh shah, The LNM IIT Jaipur (India)(santosh.jnt@gmail.com) 25/04/07 
 
if nargin < 4 
    fs = 128e3 ; % default value of sampling frequency 100kHz 
end 
if nargin < 3 
    fc = 20e3; % default value of carrier frequency 
end 
 
Down_samp = 2;  
test_data = 'E:\MATLAB\SDR_course\November7\my_speech.wav'; 
siz = wavread(test_data, 'size'); 
[data, fcar] = wavread(test_data); 
x = [data]' ; % coulnm to row vector conversion 
sound(x, fcar); 
tfplot(x, fs,' Voice', 'speech signal'); 
s_data = round((M-1)/2*(x + 1)) ; 
 
%converting this decimal data into binary data 
%b= my_de2bi(s_data1, 'right_msb',4); 
%s_data= my_bi2de(b,'right_msb'); 
 
%============================MODULATION=============================== 
if (type_of_mod == 'qam') 
y1 = my_qammod(s_data, M) ; 
elseif (type_of_mod == 'psk') 
    y1 = my_pskmod(s_data, M) ; 
end 
 
%tfplot(y, fs,' Voice', 'modulated signal'); 
 
%==================CHANNEL========================================== 
 
y = awgn(y1,20); 
 
 
%==================DEMODULATION=================================== 
if (type_of_mod == 'qam') 
z = my_qamdemod(y, M); 
elseif (type_of_mod == 'psk') 
    z = my_pskdemod(y, M); 
end 
z1 = (z - (M-1)/2) / M ;  
%filtering................ 
orig_sp = my_rrcosflt(z1, fcar, fs, .22, 3, 'fs'); 
sound(orig_sp, fcar); 
 
%==================SCATTER PLOT=================================== 
scale = modnorm(y,'peakpow',1); 
y = scale*y; % Scale the constellation. 
scatterplot(y); % Plot the scaled constellation. 
grid on; 
 
tfplot(orig_sp, fs,' Voice', 'de-modulated signal');