lowpass: make it work for k=0

This commit is contained in:
Robert Jördens 2021-06-22 22:53:51 +02:00
parent 901d625764
commit 0253214810
1 changed files with 1 additions and 2 deletions

View File

@ -25,7 +25,6 @@ impl<const N: usize> Lowpass<N> {
/// Filtered output y.
pub fn update(&mut self, x: i32, k: u8) -> i32 {
debug_assert!(k & 31 == k);
debug_assert!((k - 1) & 31 == k - 1);
// This is an unrolled and optimized first-order IIR loop
// that works for all possible time constants.
// Note T-DF-I and the zeros at Nyquist.
@ -35,6 +34,6 @@ impl<const N: usize> Lowpass<N> {
*y += dy;
x = *y - (dy >> 1);
}
x.saturating_add((self.y.len() as i32) << (k - 1))
x.saturating_add((self.y.len() as i32) << (k - 1).max(0))
}
}