Design a 4-point Low-Pass Window-Sinc filter, h1 with a cut-off frequency of 1k Hz and signal sampling frequency 20k Hz. 1. Write down the Window-Sinc equation and clearly show how did you calculate the transition frequency 2. After applying a Hamming window to h1, sketch the magnitude of h1 frequency response. Clearly label the x-axis. 3. Is this a good filter? Explain