From 2ff62ea900a246747fc3e974c38818a54a437064 Mon Sep 17 00:00:00 2001
From: LongHairedHacker <sebastian@sebastians-site.de>
Date: Thu, 24 Nov 2016 19:40:22 +0100
Subject: [PATCH] Squaring AM demodulator works

---
 src/amdemod.rs | 22 ++++++++++++++++++++++
 src/main.rs    | 12 +++++++-----
 2 files changed, 29 insertions(+), 5 deletions(-)
 create mode 100644 src/amdemod.rs

diff --git a/src/amdemod.rs b/src/amdemod.rs
new file mode 100644
index 0000000..359311e
--- /dev/null
+++ b/src/amdemod.rs
@@ -0,0 +1,22 @@
+pub struct SquaringAMDemodulator<'a> {
+    iterator: Box<Iterator<Item=f32> + 'a>,
+}
+
+impl<'a> SquaringAMDemodulator<'a> {
+    pub fn from<I>(iterator1: I) -> SquaringAMDemodulator<'a> where I: Iterator<Item=f32> + 'a {
+        SquaringAMDemodulator {
+            iterator: Box::new(iterator1),
+        }
+    }
+}
+
+impl<'a> Iterator for SquaringAMDemodulator<'a> {
+    type Item = f32;
+
+    fn next(&mut self) -> Option<Self::Item> {
+        match self.iterator.next() {
+            Some(x) => Some((x * x).sqrt()),
+            None => None
+        }
+    }
+}
diff --git a/src/main.rs b/src/main.rs
index 402532b..34c0217 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -5,18 +5,20 @@ mod sinegen;
 mod firfilter;
 mod resamplers;
 mod mixer;
+mod amdemod;
 
 use utils::float_sample_iterator;
 use sinegen::SineGenerator;
 use firfilter::FIRFilter;
 use mixer::Mixer;
+use amdemod::SquaringAMDemodulator;
 
 
 fn main() {
     let carrier_freq = 2400.0;
     let sample_freq = 48000.0;
 
-    let mut reader = match hound::WavReader::open("noaa19_short.wav") {
+    let mut reader = match hound::WavReader::open("noaa19_20160814_mono.wav") {
         Err(e) => panic!("Could not open inputfile: {}", e),
         Ok(r) => r
     };
@@ -28,6 +30,8 @@ fn main() {
     let sample_rate = reader.spec().sample_rate;
     println!("Samplerate: {}", sample_rate);
 
+    println!("{} Samples", reader.len());
+
     let samples = float_sample_iterator(&mut reader);
 
     let coeffs = vec![ -7.383784e-03,
@@ -95,10 +99,8 @@ fn main() {
         -7.383784e-03];
 
 
-
-    let sine_gen = SineGenerator::new(carrier_freq, 1.0, sample_freq);
-    let mixer = Mixer::from(sine_gen, samples);
-    let filter = FIRFilter::from(mixer, coeffs);
+    let demod = SquaringAMDemodulator::from(samples);
+    let filter = FIRFilter::from(demod, coeffs);
 
     let spec = hound::WavSpec {
         channels: 1,