Highpass FIR Filter using Kaiser

Hi all. I am new to MatLab and am interested in designing a Highpass FIR filter using the Kaiser window method. The parameters for the filter is: Cutoff f = 1500Hs, Transition width = 1200Hz, Sampling f = 32000Hz, minimum passband ripple = 0.000275dB and stopband attenuation = 90dB.

My code does not seem to reflect the results and responses that would be expected from a highpass filter, any help will be greatly appreciated. Please forgive the awkwardness and messiness of my code.

   %%HIGH PASS FILTER

format long;    

% Filter parameters

fc = 1500;      % Cutoff frequency

Df = 1200;      % Transition bandwidth

fs = 32000;     % Sampling frequency

fp = fc-fs;     % Stopband frequency

B = 8.96;       % From kaiser window

% Normalised values

fcn = fc/fs;

fpn = fp/fs;

Dfn = Df/fs;

N = ceil(5.71/Dfn); % Rounds up the value to next integer

Nh = (N-1)/2;       % Calculating mid-point of order

Wcn = 2*pi*fcn;     % Angular frequency in radians

y = Nh*Wcn;         % Defines a variable for use with sinc

beta = 8.96; % From the given parameters of min. ripple

x = beta;    % and stopband attenuation >60dB

Io = 1;

% Kaiser window

% Bessel function for Io

for k = 1:12;

    Io = Io + (((x/2)^k)/factorial(k))^2; % Bessel function for the denom.

end

denominator = Io;

i =1;

for n = -Nh:Nh;

    x = beta*(1-(2*n/(N-1))^2)^0.5; % Calculate the num. of the window

    Io = 1;

    for k =1:12;

        Io = Io + (((x/2)^k)/factorial(k))^2;

    end

    Io_of_n(i) = Io;

    i = i + 1;

end

% Ideal filter impulse response

kaiser = Io_of_n/denominator; % Creates the Kaiser window

   hD = -2*fcn*sin(Nh*Wcn/Nh*Wcn);       

filt = hD*kaiser;

% Plots

figure(1)

subplot(3,1,1)

stem(kaiser)

ylabel('Kaiser Window Function')

grid on

subplot(3,1,2)

stem(abs(fft(hD))) % impulse_resp=filter(Hd,[1 zeros(1,31)]);

ylabel('Ideal Impulse Response')

grid on

subplot(3,1,3)

stem(filt)

ylabel('Filter Frequency Response')

grid on

figure(2)

freqz(filt,1)

% Save information to disc

fid = fopen('filter.asm','w');

fprintf(fid,';Sampling frequency =%d\n',fs);

fprintf(fid,';Cutoff frequency   =%d\n',fc);

fprintf(fid,';Transition bandwidth =%d\n',Df);

fprintf(fid,';Window type used = kaiser\n\n');

fprintf(fid,'ntaps EQU\t%d\n\n',N);

i=0;

for t=1:1:N

    i=i+1;

    fprintf(fid,'h_%d\tdc\t%1.8f\n',i,filt(i));

    end

fclose(fid)

end