fs = 8000;
fpass = 2000;
fstop = 3500;

Fpass = fpass/fs;
Fstop = fstop/fs;

h = firpm(20,[0 Fpass Fstop 0.5]/0.5, [1 1 0 0]);

NFFT = 2^14;
F = [0:NFFT-1]/NFFT - 0.5;
f = F*fs;


% Ploting
subplot(221);
plot(F,abs(fftshift(fft(h,NFFT))));
axis([0 0.5 0 1.2]);
xlabel('F [cycles/sample]');
ylabel('Magnitude');
subplot(222);
plot(F,20*log10(abs(fftshift(fft(h,NFFT)))));
axis([0 0.5 -90 10]);
xlabel('f [cycles/second]');
ylabel('Magnitude (dB)');
subplot(223);
plot(f,abs(fftshift(fft(h,NFFT))));
axis([0 0.5*fs 0 1.2]);
xlabel('F [cycles/sample]');
ylabel('Magnitude');
subplot(224);
plot(f,20*log10(abs(fftshift(fft(h,NFFT)))));
axis([0 0.5*fs -90 10]);
xlabel('f [cycles/second]');
ylabel('Magnitude (dB)');

print -djpeg90 -r75 c2dfilter.jpg