Now working CSMA with TCP

src/squelch.rs

@@ -0,0 +1,34 @@
+use std::collections::VecDeque;
+
+use rand::seq::index::sample;
+
+use crate::complex::Complex32;
+
+pub struct Squelch {
+    window: VecDeque<f32>,
+    sum: f32,
+    level: f32,
+}
+
+impl Squelch {
+    pub fn new(length: usize, level: f32) -> Self {
+        Squelch {
+            window: VecDeque::from(vec![0.; length]),
+            sum: 0.,
+            level,
+        }
+    }
+
+    pub fn next(&mut self, sample: Complex32) -> Option<Complex32> {
+        let oldest = self.window.pop_back().unwrap();
+        self.window.push_front(sample.mag());
+        self.sum -= oldest;
+        self.sum += sample.mag();
+
+        if self.sum / (self.window.len() as f32) > self.level {
+            Some(sample)
+        } else {
+            None
+        }
+    }
+}