Note pulse rising and falling? (5)
I believe the answer is:
tidal
'rising and falling?' is the definition.
(I've seen this in another clue)
'note pulse' is the wordplay.
'note' becomes 'ti' (musical note as in do re mi fa so la ti).
'pulse' becomes 'dal' (I've seen this before).
'ti'+'dal'='TIDAL'
(Other definitions for tidal that I've seen before include "To do with sea movements of lunar origin" , "Ebbing and flooding" , "Pertaining to rise and fall of the sea" , "__ wave; tsunami" , "Concerning the rise and fall of the sea" .)