I would be glad if someone could answer my question. I have a bit stream of data and I want to extract the low frequency component. When post processing the data I can calculate the average value over a certain number of samples with the MATLAB operation
Then I tired to build the equivalent LPF of this operation:
$$V_o(k) = \frac 1N \big[V_i(k-1) + V_i(k-2) + \ldots + V_i(k-N)\big]$$
Plotted the equivalent filter transfer function:
And it looks like a sort of first order LPF. Now if I filter the data I don't get the same results of the average operation,
So what am I missing? The purpose of this investigation is to look for a better filter that will be implemented on FPGA to do real time processing.