The error shows not enough input arguments when use hanning window

i want to use welch method to do spectrum estimation, 50% overlap and divide data into 8 segment, however, when i use hanning window, the matlab always show error using hanning, specifically, it says not enough input arguments, i really do not know why, i hope someone can help me. Thanks

The code is like this

p1=0.99*(cos((88/180)*pi)+j*sin((88/180)*pi));

p11=0.99*(cos((88/180)*pi)-j*sin((88/180)*pi));

p2=0.98*(cos((92/180)*pi)+j*sin((92/180)*pi));

p22=0.98*(cos((92/180)*pi)-j*sin((92/180)*pi));

B=[1,0,0,0];  (zero)

a=[1,(-(p1+p11+p2+p22)),(p1*p11+p2*p22+(p1+p11)*(p2+p22)),-(((p1+p11)*p2*p22)+(p1*p11*(p2+p22))),p1*p11*p2*p22];   (pole)

x=randn(1,10000);

y=filter(B,a,x);

nfft=1024;

noverlap=0.5*nfft;

pxx=pwelch(y,hanning,noverlap);

Answer 1

[Walter Roberson]

You need to pass the window width to hanning()

http://www.mathworks.com/matlabcentral/answers/41903