I'm recording motor cortex NIRS signals from the human brain where the heart
rate(~1.5Hz), respiration(~2Hz) and Mayer wave(~0.1Hz) cloud a lot of the motor
signal that is desired.
The filtering technique has to be very phase neutral (like FIR not IIR
filtering) unlike the filter.m where a dramatic affect occurs in phase
Filtfilt.m is the usual one that is used that is effectively phase neutral.
Another is polynomial fitting.
However neither are very satisfactory or consistantly successful and can differ
dramatically in terms of phase. The signal that we are trying to recover is
Is anyone aware of a successful filtering method in matlab for phase critical
physiological signals? Even for Physiological signals in general? Or simply a
filtering technique used for phase accuracy unrelated to physiological
Any comments, code or suggestions are welcome,