zer0square
Newbie level 2
A Linear Time-Invariant system with impulse response h1[n]h1[n] is an ideal lowpass filter with cutoff frequency ωc=π/2ωc=π/2. The frequency response of the system is H1(ejω)H1(ejω). Suppose a new LTI system with impulse response h2[n]h2[n] is obtained from h1[n]h1[n] by h2[n]=(−1)n⋅h1[n]h2[n]=(−1)n⋅h1[n]. Sketch the frequency response H2(ejω)H2(ejω).