4An analog signal xa(t), band-limited to 5 Hz, is sampled at a rate of 10 samples per second to give a discrete-time signal x(n) = xa(0.1n). The discrete-time signal x(n) is then filtered with an digital FIR filter, h.Find the shortest impulse response h(n) so that
(a) The filter completely rejects the frequencies 5 Hz and 2.5 Hz. (b) The DC gain of the filter is 1.
(c) The filter has linear-phase.