hi, i am stuck halfway in my coursework. the question asked to combine 3 sine wave of different frequency and add a white noise of certain variance and then will have to go through an FIR filter to get back only one of the 3 sine wave. I was thinking to use bandpass FIR window filter. but i am stuck at coeficient calculations. how do i know what is my passband ripple, stopband magnitude? Should i look at the frequency response of my combined sine wave with noise to get all this information to filter and get the wanted sine wave? Attached is some of the things that i have worked out so far.