Yeah.
Let 's  let 's hypothesize that it 's this frequency or that frequency , and  and , uh , maybe you  maybe you could use some other cute methods to , uh , short cut it by  by uh , making some guesses ,
Yeah.
but  but uh  uh  uh , I would , uh  I mean you could make some guesses from , uh  from the auto - correlation or something but  but then , given those guesses , try , um , uh , only looking at the energy at multiples of the  of that frequency , and  and see how much of the  take the one that 's maximum. Call that the