Looking for a simple and effective notch filter
i might also recommend a low-pass filter over a notch filter unless the OP is absolutely certain, in advance, what the frequency of the "noise" is.  if the OP has less information about the high-frequency noise that the OP desires to remove (leaving the moving average), then a LPF with DC gain of 1 (or 0 dB) and a cutoff frequency lower than the lowest expected frequency component in the noise is indicated.  not a notch filter.

whether it's a Kaiser-windowed-sinc FIR or an IIR LPF (perhaps a simple 2nd-order IIR suffices) is a design and performance issue.

but i would not recommend a notch unless it is known apriori that the "noise" is sinusoidal and what the frequency of the sinusoidal "noise" is.