how to convert digital data into analog data using matlab code?

U=10; % range signal from 0 to 10
n=3 % number of bits
q=U/(2^n-1)  % quantization interval
t=0:0.1:10; % your time vector
y=abs(10*sin(t)); % your signal
% -------convert to a digital signal yd-----------
a=fix(y/q);
yd=dec2bin(a,n)
% ------you can calculate the signal yq ----------
yq=a*q 
%-------------------------------------------------
plot(t,y,'r')
hold on
plot(t,yq,'g')
hold off