44 lines
1,009 B
Racket
44 lines
1,009 B
Racket
#lang scribble/manual
|
|
@(require (for-label racket))
|
|
|
|
@title{subsample-offset}
|
|
|
|
|
|
|
|
demonstrate cubic subsample interpolation, an impulse train that can be moved between samples
|
|
|
|
@racketblock[
|
|
(with-sc3
|
|
(lambda (fd)
|
|
(send-synth
|
|
fd
|
|
"s"
|
|
(letc ((out 0)
|
|
(add-offset 0))
|
|
(let* ((i (mul (impulse 2000 0) 0.3))
|
|
(d sample-dur)
|
|
(x 4)
|
|
(o (add (sub 1 subsample-offset)
|
|
(mouse-x 0 add-offset 0 0.1)))
|
|
(r (delay-c i (mul d (add 1 x)) (mul d (add o x)))))
|
|
(offset-out out r))))))
|
|
]
|
|
|
|
Create two pulse trains one sample apart, move one relative to the
|
|
other. When cursor is at the left, the impulsese adjacent, on
|
|
the right, theye exactly 1 sample apart. View this with an
|
|
oscilloscope.
|
|
|
|
|
|
@racketblock[
|
|
(with-sc3
|
|
(lambda (fd)
|
|
(let ((t (utcr))
|
|
(dt (/ 1 (server-sample-rate-actual fd))))
|
|
(send fd (bundle (+ t 0.2)
|
|
(list (s-new1 "s" -1 1 1 "addOffset" 3))))
|
|
(send fd (bundle (+ t 0.2 dt)
|
|
(list (s-new1 "s" -1 1 1 "addOffset" 0)))))))
|
|
]
|
|
|
|
|