dc bias cleaning

src/decoder/dc_bias.rs

 use crate::codec2::Complex;
 
-// 1 seconds @ 48KHz
+// 1 second @ 48KHz
 const AVERAGE_TIME: usize = 48_000;
 
 pub struct RemoveDcBias<I: Iterator<Item = Complex>> {
@@ -29,7 +29,7 @@ impl<I: Iterator<Item = Complex>> Iterator for RemoveDcBias<I> {
 
         self.sum += val;
         self.i += 1;
-        if self.i == AVERAGE_TIME {
+        if self.i >= AVERAGE_TIME {
             self.avg = self.sum / (self.i as f32);
             self.i = 0;
             self.sum = Complex::zero();