%Daniel Linnen
%HW2 Half Duplex

clear all;
%declaring counting variables
l=1;
m=1;
count=1;
%initializing values to zero
xn=0;
sn=0;
dn=0;
echo=0;
Pxe1=0;
Pde1=0;
hang=0;
%declaring files
f1=fopen('C:\ELE 498D\testw.dat', 'r');
f2=fopen('C:\ELE 498D\test1.dat', 'r');
%initializing arrays
x=zeros(105,1);
p=zeros(11,1);
h=[-0.01,-0.05,0.1,0.3,0.2,-0.1,0.05,0.01];
%end of declaration

%start of program
while(count==1)
    %reading files
    [xn,count] = fread(f1, 1, 'short');
     if(count==0)
        break;
    end   
    [sn,count] = fread(f2, 1, 'short');
    
    l=l+1;
    %converting to integers
    xn = xn/32768;
    sn = sn/32768;
    %update the input buffer
    
    for i=105:-1:2
        x(i)=x(i-1);
    end %end for
    
    x(1)=xn;
    echo=0;
    
    %convolution (to make the echo)
    for i=98:105
        echo = echo + h(i-97) * x(i);
    end %end for
    
    %combining talker2's voice with echo, the only signal we have access too
    dn = echo + sn;
    
    %exponential
    Pxe1 = 0.95 * Pxe1 + (1-0.95) * xn * xn;
    Pde1 = 0.95 * Pde1 + (1-0.95) * dn * dn;
    
    
        
    %per 64 samples store one point
    if(l==65)        
        Pxe(m) = 10*log10(Pxe1); %converting to dB
        Pde(m) = 10*log10(Pde1);
        for(z=11:-1:2)  %shifting hang buffer
            p(z)=p(z-1);
        end
    p(1)=Pxe(m);
    
    if(Pde(m) < p(11)-3) %comparing with hang measurement in dB
        Pde(m) = Pde(m)-30; %attenuating in dB
    end
                m=m+1; %incrimenting
                Pxe1=0; %resetting values
                Pde1=0;
                l=1;
    end %end if
end % end while

%% plotting
figure(1)
plot(Pxe, 'r')
hold
plot(Pde, 'b')