I have a signal that I want to interpolate 625 times, and then decimate 12 times to get the decired result. I've read that the best way of doing this is to use a polyphase FIR filter with zero stuffing. I was planning to use steps of 5 for the interpolation, and steps of 4 at the decimation. The problem is that I'm kind of new to digital signal processing, so I don't know how to find the coeffisients for the FIR filter. I have downloaded ScopeFIR, a program that can generate FIR filter coeffisients, but there are several parameters that I have to set:
-What type of filter: Simple Parks-McClellan, Advanced Parks-McClellan, Windowed Sinc, Raised Cosine, Lth-Band (Nyquist), Inport/Boxcar, Maximally Flat, CIC
-Passband upper frequency
-Stopband lower frequency
I would be very grateful if someone could help me with these parameters, or give me a guide for finding these coeffisients in another way!
The Attempt at a Solution
I've read an enormous amount of webpages regarding this, but I just don't understand it. I have already done the programming of the filter, the only problem is finding thos coeffisients.