Frequency shift avoid aliasing has been reworked. Previously included two additional LPF's, one after interpolation and one before decimation. The two additional LPF's have been removed because the necessary filtering is already implemented in the sample rate change.
The decimation has been reworked. Previously used scipy's resample_poly() and does a decimate by 2. The problem was that it still had a large amount of energy aliasing from +fs/2 to -fs/2. The new filter uses a lower cutoff frequency which allows better rejection of aliased energy at the cost of distorting the passband of the signal.
Implements #199 (link includes design notes and commentary on changes)
Frequency shift avoid aliasing has been reworked. Previously included two additional LPF's, one after interpolation and one before decimation. The two additional LPF's have been removed because the necessary filtering is already implemented in the sample rate change.
The decimation has been reworked. Previously used scipy's resample_poly() and does a decimate by 2. The problem was that it still had a large amount of energy aliasing from +fs/2 to -fs/2. The new filter uses a lower cutoff frequency which allows better rejection of aliased energy at the cost of distorting the passband of the signal.
Implements #199 (link includes design notes and commentary on changes)