Determine ideal impulse response using inverse discrete-time Fourier transform.
An ideal low-pass filter is described in the frequency-domain by
H_d(e^(jw)) = 1 . e^(-jaw) , |w| <= w_c
0 , w_c < |w| <= PI
where w_c is called the cutoff frequency and a (denoting symbol alpha) is called the phase delay.
Determine the ideal impulse response h_d(n) using the inverse discrete-time Fourier transform.
Please note that notation X_y indicates "X subscript y" in above description.