fm demod

src/fm_demod.rs

@@ -1,4 +1,6 @@
-use crate::iq_reader::{IqChunk, IqSample};
+use crate::iq_reader::IqSample;
+
+pub type Phase = f32;
 
 pub struct FmDemod<I> {
     pub inner: I,
@@ -13,9 +15,10 @@ impl<I> FmDemod<I> {
         }
     }
 
-    pub fn process_sample(&mut self, sample: IqSample) -> IqSample {
-        // TODO: FM Demodulation
-        todo!();
+    pub fn process_sample(&mut self, sample: IqSample) -> Phase {
+        let phase_diff = sample * self.prev_sample.conj();
+        self.prev_sample = sample;
+        phase_diff.arg()
     }
 }
 
@@ -23,7 +26,7 @@ impl<I, E> Iterator for FmDemod<I>
 where
     I: Iterator<Item = Result<IqSample, E>>,
 {
-    type Item = Result<IqSample, E>;
+    type Item = Result<Phase, E>;
 
     fn next(&mut self) -> Option<Self::Item> {
         match self.inner.next()? {