Q1. Consider a system implementing a rational sampling rate change by 5/7: for this, we cascade upsampler by 5, a lowpass filter with cutoff frequency π/7 and a downsampler by 7. The lowpass filter is a 99-tap FIR.
Assume that the input works at a rate of 1000 samples per second. What is the number of multiplications per second required by the system? Assume that multiplications by zero do not count and round the number of operations to the nearest integer.
Please tell the approach on how to start this question.
The generic order of sampling rate change is "upsample", "filter", "downsample". That means that we need to run the filter at the upsampled rate, i.e 5000 but given that it is 99tap filter so shall i directly multiply 99*5000=495000. is it okay wrt the asked question or am i missing something