Discrete function estimation from Parametric Audio Equalizer

Hello,

I am making a audio equalizer on a FPGA. The filtering is going fine but it would be nice to see the frequency response of the filter. I have checked the Parametric Audio Equalizer example and the Discrete function estimation is exactly what i need. But it is not working in my own matlab test. I checked the Discrete Transfer Function Estimator block from simulink but the methode described is not working. Can somone help me with this?

The code: (y is the output and xa the input)

N=1024; % 1024 test samples
window =  hamming(N)';
ywin = window .* y';
xawin = window .* xa;
Y = fft(ywin);
X = fft(xawin);
YPSD=zeros(N,1)';  
XPSD=zeros(N,1)';
YPSD=YPSD+abs(Y).^2;  
XPSD=XPSD+abs(X).^2; 
PYX = XPSD .* conj(YPSD);
f=[0:(N)-1]*Fs/(N);
figure; plot(f,10*log10(PYX)); title('welch');
xlabel('Frequency (Hz)')
ylabel('Magnitude (dB)')