1200 bauds ?

src/main.rs

@@ -12,6 +12,7 @@ mod ted;
 mod units;
 mod windows;
 
+use cpal::traits::{DeviceTrait, HostTrait, StreamTrait};
 use egui_plot::{Legend, Line, Plot};
 use hound::WavWriter;
 use rand::{Rng, rand_core::le, seq::index::sample};
@@ -19,13 +20,22 @@ use std::{
     cell::{Cell, RefCell},
     collections::VecDeque,
     env::{self, args},
+    fmt::Display,
     fs::File,
-    io::{BufWriter, Sink, Write, stdout},
+    io::{BufWriter, Read, Sink, Write, stdout},
     ops::DerefMut,
-    sync::Arc,
+    sync::{Arc, atomic::AtomicU64, mpsc::RecvTimeoutError},
     time::Duration,
+    u64,
+};
+use tokio::{
+    io::{self, AsyncReadExt, AsyncWriteExt},
+    join,
+    net::{TcpSocket, TcpStream, UdpSocket},
+    select,
+    sync::mpsc::{UnboundedSender, error::TryRecvError, unbounded_channel},
+    time::timeout,
 };
-use tokio::{join, net::UdpSocket, select, sync::mpsc::error::TryRecvError, time::timeout};
 
 use crate::{
     bfsk::BFSKMod,
@@ -33,20 +43,23 @@ use crate::{
     filtering::{dc_block::DCBlocker, fir::FIRFilter},
     iq::IQSampler,
     nco::Nco,
+    squelch::Squelch,
     ted::elg::ELGate,
     units::frequency::hz_to_rad_per_sample,
 };
-use eframe::egui::{self, CentralPanel, Color32, debug_text::print};
+use eframe::egui::{self, CentralPanel, Color32, RichText};
 use tokio::sync::RwLock;
 use tokio::sync::mpsc::{Receiver, Sender, channel};
 
-const BAUD_RATE: u32 = 1000;
+const BAUD_RATE: u32 = 1200;
 const SAMPLE_RATE: u32 = 48000;
 
 // Modulation parameters
 const CENTER_FREQ: f32 = 1700.;
 const DEVIATION: f32 = 500.;
 
+static mut INSTANCE_ID: u32 = 0;
+
 pub enum SampleSenderCommand {
     Open,
     Close,
@@ -94,11 +107,97 @@ impl SampleSender for WavSampleSender {
     }
 }
 
+struct FSKReceiver {
+    eye_sender: Sender<Vec<f32>>,
+    phase_lowpass: FIRFilter,
+    elg: ELGate,
+    last_byte: u8,
+    frame_constructor: FrameConstructor,
+    bit_count: Option<u32>,
+    last_sample: Complex32,
+}
+
+impl FSKReceiver {
+    fn new(eye_sender: Sender<Vec<f32>>) -> Self {
+        let samples_per_symbol = (SAMPLE_RATE as f32) / (BAUD_RATE as f32);
+
+        let mut phase_lowpass = FIRFilter::new(&vec![
+            Complex32::new(1., 0.);
+            samples_per_symbol as usize / 2
+        ]);
+        phase_lowpass.normalize_dc();
+        //let mut dc_block = DCBlocker::new(0.999);
+        //let mut dc_block = DCBlocker::new(1.);
+
+        let loop_i = 0.03;
+        let loop_p = 0.1;
+        let mut loop_ir = vec![Complex32::new(loop_i, 0.); samples_per_symbol as usize / 2];
+        loop_ir.push(Complex32::new(loop_p, 0.));
+        let elg = ELGate::new(samples_per_symbol, FIRFilter::new(&loop_ir));
+        Self {
+            //iq_sampler: IQSampler::new(hz_to_rad_per_sample(CENTER_FREQ, SAMPLE_RATE as f32)),
+            phase_lowpass,
+            elg,
+            last_byte: 0x00u8,
+            frame_constructor: FrameConstructor::new(),
+            bit_count: None,
+            eye_sender,
+            last_sample: Complex32::new(1., 0.),
+        }
+    }
+
+    async fn receive(&mut self, iq: Complex32) -> Result<Option<Frame>, FrameConstructionError> {
+        // Frame reconstruction
+        let dphi = self
+            .phase_lowpass
+            .next_real((self.last_sample * iq.conj()).arg());
+        self.last_sample = iq;
+        if let Some((bit_sample, eye)) = self.elg.next_eye(dphi) {
+            let _ = self.eye_sender.send(eye).await;
+            self.last_byte >>= 1;
+            self.last_byte |= ((bit_sample > 0.) as u8) << 7;
+            //last_byte <<= 1;
+            //last_byte |= ((bit_sample < 0.) as u8);
+            self.bit_count = self.bit_count.map(|x| x + 1);
+
+            if let None = self.bit_count
+                && self.last_byte == 0xD8
+            {
+                // Potential frame starts
+                self.last_byte = 0;
+                self.frame_constructor = FrameConstructor::new();
+                self.bit_count = Some(0);
+            }
+
+            if let Some(8) = self.bit_count {
+                let frame_opt = self.frame_constructor.add_byte(self.last_byte);
+                self.bit_count = Some(0);
+                //print!("{}", last_byte as char);
+                print!(".{:x}.", self.last_byte);
+                let _ = std::io::stdout().flush();
+                return frame_opt;
+            }
+        }
+        return Ok(None);
+    }
+}
+
+#[derive(Debug)]
+enum TransceiverState {
+    Waiting,
+    Receiving,
+    EOT,
+    SendingAck,
+    Sending,
+    Listening,
+}
+
 struct Transceiver {
     tx_stream: Sender<Vec<u8>>,
     rx_stream: Receiver<Vec<u8>>,
 
     eye_receiver: Receiver<Vec<f32>>,
+    state_receiver: Receiver<TransceiverState>,
 }
 
 impl Transceiver {
@@ -118,159 +217,141 @@ impl Transceiver {
         self.eye_receiver.try_recv()
     }
 
-    pub fn start(
-        mut sample_stream: Receiver<f32>,
-        mut sample_sender: Sender<SampleSenderCommand>,
-    ) -> Self {
-        let (mut eyes_tx, eyes_rx) = channel::<Vec<f32>>(1024);
+    pub fn try_recv_state(&mut self) -> Result<TransceiverState, TryRecvError> {
+        self.state_receiver.try_recv()
+    }
 
-        let (rx_stream_sender, rx_stream_receiver) = channel::<Vec<u8>>(1024);
+    pub fn start(mut sample_stream: Receiver<f32>, mut sample_sender: Sender<Vec<f32>>) -> Self {
+        let mut resend: Option<Vec<u8>> = None;
+        let (mut eyes_tx, eyes_rx) = channel::<Vec<f32>>(1024);
+        let (mut state_tx, state_rx) = channel::<TransceiverState>(1024);
+        state_tx.try_send(TransceiverState::Waiting);
+
+        let (rx_stream_sender, mut rx_stream_receiver) = channel::<Vec<u8>>(1024);
         let (tx_stream_sender, mut tx_stream_receiver) = channel::<Vec<u8>>(1024);
 
+        let receiving = Arc::new(RwLock::new(false));
         tokio::spawn(async move {
-            let squelch_sum = 0.;
-            loop {}
+            let mut squelch = Squelch::new(200, 0.1);
+            let mut iq_sampler =
+                IQSampler::new(hz_to_rad_per_sample(CENTER_FREQ, SAMPLE_RATE as f32));
+
+            let mut current_message = None;
+            loop {
+                select! {
+                    _ = async {
+                            while squelch.next(iq_sampler.sample(sample_stream.recv().await.unwrap())).is_none() {}
+                    }
+                    =>
+                    {
+                        state_tx.try_send(TransceiverState::Receiving);
+                        // Wait for end of tranmission
+                        let mut recv = Some(FSKReceiver::new(eyes_tx.clone()));
+                        let mut send_ack = false;
+                        while let Some(iq) = squelch.next(iq_sampler.sample(sample_stream.recv().await.unwrap()))
+                        {
+                            if recv.as_ref().is_some()
+                            {
+                                match recv.as_mut().unwrap().receive(iq).await
+                                {
+                                    Ok(Some(Frame::Data(_))) => {println!("GOT DATA"); send_ack = true; recv = None; state_tx.try_send(TransceiverState::EOT);},
+                                    Ok(Some(Frame::Ack)) => {current_message = None; recv = None; state_tx.try_send(TransceiverState::EOT);},
+                                    Err(()) => {recv = None;},
+                                    _ => {}
+                                }
+                            }
+                        }
+                        if send_ack
+                        {
+                            state_tx.try_send(TransceiverState::SendingAck);
+                            Self::transmit(Frame::Ack, &mut sample_sender).await;
+                        }
+                        state_tx.try_send(TransceiverState::Waiting);
+                    },
+                    message = async
+                    {
+                        if current_message.is_none()
+                        {
+                            current_message = Some((tx_stream_receiver).recv().await.unwrap());
+                        }
+                        state_tx.try_send(TransceiverState::Listening);
+                        tokio::time::sleep(Duration::from_millis(500 * rand::random_range(1..6))).await;
+                        current_message.as_ref().unwrap()
+                    } =>
+                    {
+                        state_tx.try_send(TransceiverState::Sending);
+                        println!("Sending message");
+                        Self::transmit(Frame::Data(message.clone()), &mut sample_sender).await;
+                        //current_message = None;
+                        println!("Sent message");
+                        state_tx.try_send(TransceiverState::Waiting);
+                    }
+                };
+            }
         });
 
         Self {
             eye_receiver: eyes_rx,
+            state_receiver: state_rx,
 
             tx_stream: tx_stream_sender,
             rx_stream: rx_stream_receiver,
         }
     }
 
-    async fn squelch_detector(sample_stream: &mut Receiver<f32>) {
-        let length = 200;
-        let level = 0.4;
-        let mut iq_sampler = IQSampler::new(hz_to_rad_per_sample(CENTER_FREQ, SAMPLE_RATE as f32));
-        let mut squelch_sum = 0.;
-        let mut i = 0;
-        while let Some(smpl) = sample_stream.recv().await {
-            let iq = iq_sampler.sample(smpl);
-            squelch_sum += iq.mag() / length as f32;
-            i += 1;
-
-            if i >= length {
-                if squelch_sum >= level {
-                    return;
-                }
-                i = 0;
-                squelch_sum = 0.;
-            }
-        }
-    }
-
-    pub async fn transmit(frame: Frame, samples_sender: &mut Sender<SampleSenderCommand>) {
+    pub async fn transmit(frame: Frame, samples_sender: &mut Sender<Vec<f32>>) {
         let bytes = frame.bytes();
-        let mut bit_stream = bytes.iter().flat_map(|x| byte_to_bits(*x));
-        let modulator = BFSKMod::new(
-            (SAMPLE_RATE as f32 / BAUD_RATE as f32).round() as u32,
-            hz_to_rad_per_sample(DEVIATION, SAMPLE_RATE as f32),
-            &mut bit_stream,
-        );
+        let data = bytes
+            .iter()
+            .flat_map(|x| byte_to_bits(*x))
+            .collect::<Vec<_>>();
 
-        let up_lo = Nco::new(hz_to_rad_per_sample(CENTER_FREQ, SAMPLE_RATE as f32));
-        samples_sender.send(SampleSenderCommand::Open).await;
-        for (m, up) in modulator.zip(up_lo) {
-            let sample = m * up;
-            samples_sender
-                .send(SampleSenderCommand::Sample(sample.re))
-                .await;
-        }
-        samples_sender.send(SampleSenderCommand::Close).await;
-    }
-
-    async fn receive(
-        sample_stream: &mut Receiver<f32>,
-        eye_sender: &mut Sender<Vec<f32>>,
-    ) -> Result<Frame, FrameConstructionError> {
-        let mut iq_sampler = IQSampler::new(hz_to_rad_per_sample(CENTER_FREQ, SAMPLE_RATE as f32));
-
-        let samples_per_symbol = (SAMPLE_RATE as f32) / (BAUD_RATE as f32);
-
-        let correllator_length = samples_per_symbol as usize;
-        let mut pos_nco = Nco::new(hz_to_rad_per_sample(DEVIATION, SAMPLE_RATE as f32));
-        let mut neg_nco = Nco::new(hz_to_rad_per_sample(-DEVIATION, SAMPLE_RATE as f32));
-        let pos_ir = (0..correllator_length).map(|i| {
-            pos_nco.step();
-            pos_nco.cexp() * windows::blackmann(i as f32 / correllator_length as f32)
-        });
-        let neg_ir = (0..correllator_length).map(|i| {
-            neg_nco.step();
-            neg_nco.cexp() * windows::blackmann(i as f32 / correllator_length as f32)
-        });
-        let mut pos_correllator = FIRFilter::new(&pos_ir.collect::<Vec<_>>());
-        let mut neg_correllator = FIRFilter::new(&neg_ir.collect::<Vec<_>>());
-        pos_correllator.normalize_freq(hz_to_rad_per_sample(DEVIATION, SAMPLE_RATE as f32));
-        neg_correllator.normalize_freq(hz_to_rad_per_sample(-DEVIATION, SAMPLE_RATE as f32));
-
-        let mut matched_lowpass = FIRFilter::new(&vec![
-            Complex32::new(1., 0.);
-            samples_per_symbol as usize / 2
-        ]);
-        matched_lowpass.normalize_freq(hz_to_rad_per_sample(DEVIATION, SAMPLE_RATE as f32));
-        //let mut dc_block = DCBlocker::new(0.999);
-        let mut dc_block = DCBlocker::new(1.);
-
-        let loop_i = 0.0;
-        let loop_p = 0.1;
-        let mut loop_ir = vec![Complex32::new(loop_i, 0.); samples_per_symbol as usize];
-        loop_ir.push(Complex32::new(loop_p, 0.));
-        let mut elg = ELGate::new(samples_per_symbol, FIRFilter::new(&loop_ir));
-
-        // Frame reconstruction
-        let mut last_byte = 0x00u8;
-        let mut frame_constructor = FrameConstructor::new();
-        let mut bit_count: Option<u32> = None;
-        while let Some(sample) = sample_stream.recv().await {
-            let iq = iq_sampler.sample(sample);
-            let matched =
-                matched_lowpass
-                    .next_real(dc_block.next_real(
-                        pos_correllator.next(iq).mag() - neg_correllator.next(iq).mag(),
-                    ));
-            if let Some((bit_sample, eye)) = elg.next_eye(matched) {
-                let _ = eye_sender.send(eye).await;
-                last_byte >>= 1;
-                last_byte |= ((bit_sample > 0.) as u8) << 7;
-                //last_byte <<= 1;
-                //last_byte |= ((bit_sample < 0.) as u8);
-                bit_count = bit_count.map(|x| x + 1);
-
-                if let None = bit_count
-                    && last_byte == 0xD8
-                {
-                    // Potential frame starts
-                    last_byte = 0;
-                    frame_constructor = FrameConstructor::new();
-                    bit_count = Some(0);
-                }
-
-                if let Some(8) = bit_count {
-                    let frame_opt = frame_constructor.add_byte(last_byte);
-                    bit_count = Some(0);
-                    //print!("{}", last_byte as char);
-                    print!(".{:x}.", last_byte);
-                    let _ = std::io::stdout().flush();
-                    if let Ok(Some(Frame(ref frame_data))) = frame_opt {
-                        println!("Got data");
-                        return Ok(Frame(frame_data.to_vec()));
-                    }
-
-                    if let Err(()) = frame_opt {
-                        // Erroneous frame
-                        println!("Error");
-                        return Err(());
-                    }
-                }
+        let sample_per_symbols = SAMPLE_RATE / BAUD_RATE;
+        let bitstream = (0..(bytes.len() * 8 * sample_per_symbols as usize)).map(|i| {
+            if data[i / sample_per_symbols as usize] {
+                1.
+            } else {
+                -1.
             }
+        });
+
+        // Synthesise impulse response
+        let mut impulse_response =
+            vec![Complex32::zero(); sample_per_symbols as usize].into_boxed_slice();
+        for (i, x) in impulse_response.iter_mut().enumerate() {
+            *x = Complex32::new(
+                windows::gaussian(0.3, i as f32 / sample_per_symbols as f32),
+                0.,
+            );
         }
-        return Err(());
+
+        let mut gaussian_filter = FIRFilter::new(&impulse_response);
+        gaussian_filter.normalize_dc();
+        let filtered_bitstream = bitstream.map(|x| gaussian_filter.next_real(x));
+
+        let mut nco = Nco::new(0.);
+        let mut lo = Nco::new(hz_to_rad_per_sample(CENTER_FREQ, SAMPLE_RATE as f32));
+
+        // Generate passband
+        let samples = filtered_bitstream
+            .map(|f| {
+                nco.set_frequency(hz_to_rad_per_sample(f * DEVIATION, SAMPLE_RATE as f32));
+                nco.step_n(1);
+                lo.step_n(1);
+                (nco.cexp() * lo.cexp()).re
+            })
+            .collect::<Vec<_>>();
+
+        let len = samples.len();
+        samples_sender.send(samples).await.unwrap();
+        tokio::time::sleep(Duration::from_secs_f32(len as f32 / SAMPLE_RATE as f32)).await;
     }
 }
 
-struct Frame(Vec<u8>);
+enum Frame {
+    Data(Vec<u8>),
+    Ack,
+}
 
 type FrameConstructionError = ();
 pub struct FrameConstructor {
@@ -291,12 +372,17 @@ impl FrameConstructor {
     }
 
     pub fn add_byte(&mut self, byte: u8) -> Result<Option<Frame>, FrameConstructionError> {
-        if self.frame.is_empty() && byte != 0x4C && !self.started {
+        if self.frame.is_empty() && byte != 0xC4 && byte != 0x4C && !self.started {
             println!("Wrong type {:x}", byte);
             self.started = true;
             return Err(());
         }
 
+        if self.frame.is_empty() && byte == 0xC4 && !self.started {
+            self.started = true;
+            return Ok(Some(Frame::Ack));
+        }
+
         if self.frame.is_empty() && byte == 0x4C && !self.started {
             self.started = true;
             return Ok(None);
@@ -317,7 +403,9 @@ impl FrameConstructor {
         if self.frame_countdown.unwrap() == 0 {
             // All data has been received
             if self.checksum == byte {
-                return Ok(Some(Frame(self.frame.iter().skip(2).copied().collect())));
+                return Ok(Some(Frame::Data(
+                    self.frame.iter().skip(2).copied().collect(),
+                )));
             }
 
             println!("Checksum failed");
@@ -337,34 +425,51 @@ impl Frame {
         let mut output_bytes = vec![];
 
         // Initial training sequence
-        output_bytes.append(&mut vec![0b01010101; 64]);
+        output_bytes.append(&mut vec![0b01010101; 32]);
 
         // Preamble byte
         output_bytes.push(0xD8);
 
-        let x = &self.0;
-        assert!(x.len() < 65536, "Data size over MTU");
+        // Command
+        match self {
+            Frame::Data(x) => {
+                assert!(x.len() < 65536, "Data size over MTU");
 
-        output_bytes.push(0x4C); // DATA FRAME
+                output_bytes.push(0x4C); // DATA FRAME
 
-        let len_u16 = x.len() as u16;
-        output_bytes.push((len_u16 & 0xFF).try_into().unwrap());
-        output_bytes.push(((len_u16 >> 8) & 0xFF).try_into().unwrap());
+                let len_u16 = x.len() as u16;
+                output_bytes.push((len_u16 & 0xFF).try_into().unwrap());
+                output_bytes.push(((len_u16 >> 8) & 0xFF).try_into().unwrap());
 
-        let mut checksum = 0u8;
-        x.iter().for_each(|x| checksum ^= x);
-        output_bytes.extend(x.iter());
+                let mut checksum = 0u8;
+                x.iter().for_each(|x| checksum ^= x);
+                output_bytes.extend(x.iter());
 
-        output_bytes.push(checksum);
+                output_bytes.push(checksum);
+            }
+            Frame::Ack => {
+                output_bytes.push(0xC4); // ACK FRAME
+            }
+        }
 
         // SEND EOT
-        output_bytes.extend(std::iter::repeat_n(4, 32));
+        output_bytes.extend(std::iter::repeat_n(4, 16));
         output_bytes
     }
 }
 
 #[tokio::main]
 async fn main() {
+    // Read instance
+    let id = std::env::args().collect::<Vec<_>>()[1]
+        .parse::<u32>()
+        .expect("NO INPUT ID");
+    assert!(id == 0 || id == 1);
+
+    unsafe {
+        INSTANCE_ID = id;
+    };
+
     //Transceiver::transmit(Frame::Data("Skibditoilet".repeat(100).bytes().collect::<Vec<_>>()), &mut WavSampleSender{}).await;
     //Transceiver::transmit(Frame::Ack, &mut WavSampleSender::default()).await;
     //return;
@@ -388,99 +493,109 @@ impl SampleSender for DummySampleSender {
 }
 
 struct EguiApp {
-    a_transceiver: Transceiver,
-    b_transceiver: Transceiver,
+    transceiver: Transceiver,
 
-    eyes_a: VecDeque<Vec<f32>>,
-    eyes_b: VecDeque<Vec<f32>>,
+    eyes: VecDeque<Vec<f32>>,
+    current_state: TransceiverState,
 }
 impl EguiApp {
     fn new(_cc: &eframe::CreationContext<'_>) -> Self {
-        let (up_a_sender, mut up_a_receiver) = channel::<SampleSenderCommand>(1024);
-        let (down_a_sender, down_a_receiver) = channel::<f32>(1024);
+        let (up_sender, mut up_receiver) = channel::<Vec<f32>>(16);
+        let (down_sender, down_receiver) = channel::<f32>(1024);
 
-        let (up_b_sender, mut up_b_receiver) = channel::<SampleSenderCommand>(1024);
-        let (down_b_sender, down_b_receiver) = channel::<f32>(1024);
+        let transceiver = Transceiver::start(down_receiver, up_sender);
 
-        let (a2b_tx, mut a2b_rx) = channel::<f32>(1024);
-        let (b2a_tx, mut b2a_rx) = channel::<f32>(1024);
+        let instance_id = unsafe { INSTANCE_ID };
+        tokio::task::spawn(async move {
+            println!("Waiting for connection ...");
 
-        let a_txrx = Transceiver::start(down_a_receiver, up_a_sender);
-        let b_txrx = Transceiver::start(down_b_receiver, up_b_sender);
+            // let socket = Arc::new(
+            //     UdpSocket::bind(format!("0.0.0.0:{}", 9000 + instance_id))
+            //         .await
+            //         .unwrap(),
+            // );
+            // socket
+            //     .connect(format!("127.0.0.1:{}", 9000 + (1 - instance_id)))
+            //     .await
+            //     .unwrap();
 
-        // A dummy channel
-        tokio::spawn(async move {
-            //let rng = rand::thread_rng();
-            let mut sending = false;
-            loop {
-                let noise = rand::random::<f32>() * 0.1;
-                let mut sample = 0.;
+            // Receiving end
+            let host = cpal::default_host();
 
-                match up_a_receiver.try_recv() {
-                    Ok(SampleSenderCommand::Open) => {
-                        sending = true;
-                        println!("open");
-                    }
-                    Ok(SampleSenderCommand::Close) => {
-                        sending = false;
-                        println!("close");
-                    }
-                    Ok(SampleSenderCommand::Sample(x)) => {
-                        sample = x;
-                    }
-                    _ => {}
-                }
+            let device = host.default_input_device().expect("No input device");
+            let mut config = device
+                .supported_input_configs()
+                .unwrap()
+                .next()
+                .unwrap()
+                .with_sample_rate(cpal::SampleRate(48000));
 
-                if sending {
-                    // Flush receiver buffer but ignore
-                    while let Ok(_) = b2a_rx.try_recv() {}
+            let stream = device
+                .build_input_stream(
+                    &config.into(),
+                    move |data: &[f32], _| {
+                        for x in data.iter() {
+                            let _ = down_sender.blocking_send(*x * 30.); // non-blocking send
+                        }
+                    },
+                    move |err| eprintln!("Stream error: {}", err),
+                    None,
+                )
+                .unwrap();
+            stream.play().unwrap();
 
-                    // Send to other
-                    a2b_tx.send(sample + noise).await;
-                } else if let Ok(down_sample) = b2a_rx.try_recv() {
-                    down_a_sender.send(down_sample).await;
-                }
-            }
-        });
+            let device = host.default_output_device().unwrap();
+            let mut supported_configs_range = device.supported_output_configs().unwrap();
+            let supported_config = supported_configs_range
+                .find(|config| {
+                    config.sample_format() == cpal::SampleFormat::F32
+                        && config.min_sample_rate().0 <= 48000
+                        && config.max_sample_rate().0 >= 48000
+                })
+                .expect("Device does not support 48kHz f32 output");
+            let config = supported_config
+                .with_sample_rate(cpal::SampleRate(48_000))
+                .config();
 
-        // B dummy channel
-        tokio::spawn(async move {
-            let mut sending = false;
-            loop {
-                let noise = rand::random::<f32>() * 0.1;
-                let mut sample = 0.;
+            while let Some(stream) = up_receiver.recv().await {
+                let stream_len = stream.len();
+                let progression = Arc::new(AtomicU64::new(0));
+                let (finished_tx, mut finished_rx) = channel::<()>(16);
 
-                match up_b_receiver.try_recv() {
-                    Ok(SampleSenderCommand::Open) => {
-                        sending = true;
-                    }
-                    Ok(SampleSenderCommand::Close) => {
-                        sending = false;
-                    }
-                    Ok(SampleSenderCommand::Sample(x)) => {
-                        sample = x;
-                    }
-                    _ => {}
-                }
+                let send_stream = device
+                    .build_output_stream(
+                        &config,
+                        move |data: &mut [f32], _: &cpal::OutputCallbackInfo| {
+                            for d in data.iter_mut() {
+                                if progression.load(std::sync::atomic::Ordering::Relaxed) as usize
+                                    == stream.len()
+                                {
+                                    let _ = finished_tx.blocking_send(());
+                                    break;
+                                }
 
-                if sending {
-                    // Flush receiver buffer but ignore
-                    while let Ok(_) = a2b_rx.try_recv() {}
-
-                    // Send to other
-                    b2a_tx.send(sample + noise).await;
-                } else if let Ok(down_sample) = a2b_rx.try_recv() {
-                    down_b_sender.send(down_sample).await;
-                }
+                                *d = stream[progression
+                                    .fetch_add(1, std::sync::atomic::Ordering::Relaxed)
+                                    as usize]
+                                    * 0.1; // TODO
+                            }
+                        },
+                        move |err| {
+                            eprintln!("Stream error: {}", err);
+                        },
+                        None,
+                    )
+                    .unwrap();
+                send_stream.play().unwrap();
+                let _ = finished_rx.recv().await;
             }
         });
 
         EguiApp {
-            a_transceiver: a_txrx,
-            b_transceiver: b_txrx,
+            transceiver,
 
-            eyes_a: VecDeque::new(),
-            eyes_b: VecDeque::new(),
+            eyes: VecDeque::new(),
+            current_state: TransceiverState::Waiting,
         }
     }
 }
@@ -490,73 +605,51 @@ impl eframe::App for EguiApp {
         egui::CentralPanel::default().show(ctx, |ui| {
             let max_eyes = 100;
 
-            while let Ok(eye) = self.a_transceiver.try_recv_eye() {
-                self.eyes_a.push_back(eye);
+            while let Ok(eye) = self.transceiver.try_recv_eye() {
+                self.eyes.push_back(eye);
             }
-            while self.eyes_a.len() > max_eyes {
-                self.eyes_a.pop_front();
+            while self.eyes.len() > max_eyes {
+                self.eyes.pop_front();
+            }
+            if let Ok(new_state) = self.transceiver.try_recv_state() {
+                self.current_state = new_state;
             }
 
-            while let Ok(eye) = self.b_transceiver.try_recv_eye() {
-                self.eyes_b.push_back(eye);
-            }
-            while self.eyes_b.len() > max_eyes {
-                self.eyes_b.pop_front();
-            }
+            ui.horizontal(|ui| {
+                if ui.button("Start").clicked() {
+                    let snd = self.transceiver.get_sender();
+                    let data = (0..rand::random_range(50..250))
+                        .map(|_| rand::random::<char>() as u8)
+                        .collect::<Vec<_>>();
 
-            ui.columns(2, |uis| {
-                Plot::new("EyeA")
-                    .legend(Legend::default())
-                    .show(&mut uis[0], |plot_ui| {
-                        //plot_ui.set_auto_bounds(Vec2b { x: false, y: false });
-                        for eye in self.eyes_a.iter() {
-                            let line = Line::new(
-                                "EyeA",
-                                eye.iter()
-                                    .enumerate()
-                                    .map(|(i, x)| [i as f64, *x as f64])
-                                    .collect::<Vec<_>>(),
-                            )
-                            .color(Color32::LIGHT_GREEN);
-                            plot_ui.line(line);
-                        }
-                    });
-
-                if uis[0].button("Start").clicked() {
-                    let snd = self.a_transceiver.get_sender();
                     tokio::spawn(async move {
-                        let _ = snd
-                            .send("Skibditoilet".repeat(10).as_bytes().to_vec())
-                            .await;
+                        let _ = snd.send(data).await;
                     });
                 }
 
-                Plot::new("EyeB")
-                    .legend(Legend::default())
-                    .show(&mut uis[1], |plot_ui| {
-                        //plot_ui.set_auto_bounds(Vec2b { x: false, y: false });
-                        for eye in self.eyes_b.iter() {
-                            let line = Line::new(
-                                "EyeB",
-                                eye.iter()
-                                    .enumerate()
-                                    .map(|(i, x)| [i as f64, *x as f64])
-                                    .collect::<Vec<_>>(),
-                            )
-                            .color(Color32::LIGHT_GREEN);
-                            plot_ui.line(line);
-                        }
-                    });
-
-                if uis[1].button("Start").clicked() {
-                    let snd = self.b_transceiver.get_sender();
-                    tokio::spawn(async move {
-                        let _ = snd
-                            .send("Skibditoilet".repeat(10).as_bytes().to_vec())
-                            .await;
-                    });
-                }
+                ui.label(
+                    RichText::new(format!("{:?}", self.current_state))
+                        .size(35.)
+                        .color(Color32::LIGHT_GREEN),
+                );
             });
+
+            Plot::new("EyeA")
+                .legend(Legend::default())
+                .show(ui, |plot_ui| {
+                    //plot_ui.set_auto_bounds(Vec2b { x: false, y: false });
+                    for eye in self.eyes.iter() {
+                        let line = Line::new(
+                            "EyeA",
+                            eye.iter()
+                                .enumerate()
+                                .map(|(i, x)| [i as f64, *x as f64])
+                                .collect::<Vec<_>>(),
+                        )
+                        .color(Color32::LIGHT_GREEN);
+                        plot_ui.line(line);
+                    }
+                });
         }); // Central panel
 
         std::thread::sleep(Duration::from_millis(16));

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
+        }
+    }
+}

src/windows.rs

@@ -10,18 +10,20 @@ pub fn bartlett(t: f32) -> f32 {
     if t < 0.5 { 2. * t } else { 2. - 2. * t }
 }
 
-pub fn hann(t: f32) -> f32
-{
+pub fn hann(t: f32) -> f32 {
     0.5 - 0.5 * (2. * PI * t).cos()
 }
 
-pub fn hamming(t: f32) -> f32
-{
+pub fn hamming(t: f32) -> f32 {
     0.54 - 0.46 * (2. * PI * t).cos()
 }
 
-pub fn blackmann(t: f32) -> f32
-{
+pub fn blackmann(t: f32) -> f32 {
     let x = 2. * PI * t;
     0.45 - 0.5 * x.cos() + 0.08 * (2. * x).cos()
 }
+
+pub fn gaussian(sigma: f32, t: f32) -> f32 {
+    let sq = (t - 0.5) / sigma;
+    (-sq * sq).exp()
+}