Use single set of taps for positive and negative filters.
Reverse taps (since new samples are pushed into buffer from the high end).
Make complex multiply explicit to avoid fancy but irrelevant arithmetic checks.
Compute negative filter from conjugation of positive filter taps.
Move filter power and difference calculations into MatchedFilter.
Less than optimal for plain FSK, but flexible enough to also support GFSK/GMSK. Not at all optimized for SIMD instructions, so may not perform adequately at Bluetooth/GSM rates.
