t_offset= 0.65;

s1= y(t_offset * fs : ((t_offset + 0.03) * fs) - 1);

temp= zeros(16,1);

s1= cat(1, temp, s1);

s1= cat(1, s1, temp);

S= fft(s1);

S= S(1 : length(s)/2);

Smag= abs(S);

SmagdB= 20 .* log10(Smag);

Sphi= atan(imag(S)./real(S));

f= linspace(0, fs/2, length(SmagdB));

t= linspace(t_offset, t_offset + 0.03, length(s1));

subplot 311

plot(t, s1)

axis tight

xlabel('Time (sec)')

ylabel('Amplitude  ')

title('Voiced Vowel /a/, 0.65 to 0.68 seconds  ')

subplot 312

plot(f, SmagdB)

axis tight

xlabel('Freq (Hz)')

ylabel('dB')

title('Magnitude Response  ')

subplot 313

plot(f, Sphi)

axis tight

xlabel('Freq (Hz)')

ylabel('radians')

title('Phase Response ')