Re:Bessel Beam
by 0xfaded on Tuesday August 28, 2018 @11:10AM
(#17859367)
My first encounter with Bessel functions was from a professor who in his youth had built digital amplifiers -- before dsps could switch at 44k Hertz. (From memory he had a 1k pwm)
He did it by predicting the position of the magnet in the speaker coil by fitting a function over the last few known positions.
Bessel functions are othogonal, and their Fourier transforms are the base polynomials band limited between -pi and pi. His argument was that by fitting a sum of Bessel functions to a sequence captured periodic signals.
I've used this trick several times, and love the "what is this black magic" reaction I get when showing it to others. Guess the cat's out of the bag now...
He did it by predicting the position of the magnet in the speaker coil by fitting a function over the last few known positions.
Bessel functions are othogonal, and their Fourier transforms are the base polynomials band limited between -pi and pi. His argument was that by fitting a sum of Bessel functions to a sequence captured periodic signals.
I've used this trick several times, and love the "what is this black magic" reaction I get when showing it to others. Guess the cat's out of the bag now...