diff --git a/src/dsp_common/carrier.rs b/src/dsp_common/carrier.rs
index e835823..37b98c0 100644
--- a/src/dsp_common/carrier.rs
+++ b/src/dsp_common/carrier.rs
@@ -1,5 +1,7 @@
 use cpal::Sample;
-use tracing::{trace};
+use tracing::trace;
+
+use super::sample::PcmSample;
 
 const TAU: f64 = 2.0 * std::f64::consts::PI;
 
@@ -11,47 +13,77 @@ pub struct TwoStateCarrier {
     phase_high: f64,
 }
 
-type PcmSample = i64;
-
 pub trait Carrier {
     fn byte_into_fsk_samples(&mut self, byte: &u8) -> Vec<PcmSample>;
+    fn idle(&mut self) -> [PcmSample; 8];
 }
 
 impl Carrier for TwoStateCarrier {
+    /// turn a u8 into bits &do FSK on the carrier for each, returning samples
     fn byte_into_fsk_samples(&mut self, byte: &u8) -> Vec<PcmSample> {
-        let mut bits: [u8; 8] = [0, 0, 0, 0, 0, 0, 0, 0];
-        let mut out: Vec<i64> = vec![];
+        //let mut bits: [u8; 8] = [0, 0, 0, 0, 0, 0, 0, 0];
+        let mut out: Vec<PcmSample> = vec![];
 
-        // MSb first
-        bits[0] = (byte     ) & 1;
-        bits[1] = (byte >> 1) & 1;
-        bits[2] = (byte >> 2) & 1;
-        bits[3] = (byte >> 3) & 1;
-        bits[4] = (byte >> 4) & 1;
-        bits[5] = (byte >> 5) & 1;
-        bits[6] = (byte >> 6) & 1;
-        bits[7] = (byte >> 7) & 1;
+        // LSb first
+        //        bits[0] = (byte     ) & 1;
+        //        bits[1] = (byte >> 1) & 1;
+        //        bits[2] = (byte >> 2) & 1;
+        //        bits[3] = (byte >> 3) & 1;
+        //        bits[4] = (byte >> 4) & 1;
+        //        bits[5] = (byte >> 5) & 1;
+        //        bits[6] = (byte >> 6) & 1;
+        //        bits[7] = (byte >> 7) & 1;
 
-        for (i, bit) in bits.into_iter().enumerate() {
-            if bit == 0 {
-                trace!("low bit {} in fsk code", i);
+        // for each bit in the byte (LSb..=MSb)...
+        for bit_place in 1..=8 {
+            // if the bit is high...
+            if (byte >> bit_place) & 1 == 0 {
+                // while the signal hasn't yet completed a single period...
                 while (self.phase_low) < self.sample_rate / self.freq_low {
-                    out.push((self.phase_low * TAU * self.freq_low / self.sample_rate).sin().to_sample::<i64>());
+                    // push the next sample of the relative sine wave
+                    out.push(PcmSample::F64(
+                        (self.phase_low * TAU * self.freq_low
+                            / self.sample_rate)
+                            .sin(),
+                    ));
+                    // next sample
                     self.phase_low += 1.0;
                 }
-                self.phase_low = self.phase_low % (self.sample_rate / self.freq_high);
-            } else if bit == 1 {
-                trace!("high bit {} in fsk code", i);
+                // if phase counter exceeds 1 period, drop it down again
+                self.phase_low =
+                    self.phase_low % (self.sample_rate / self.freq_low);
+            } else if (byte >> bit_place) & 1 == 1 {
                 while (self.phase_high) < self.sample_rate / self.freq_high {
-                    out.push((self.phase_high * TAU * self.freq_low / self.sample_rate).sin().to_sample::<i64>());
+                    out.push(PcmSample::F64(
+                        (self.phase_high * TAU * self.freq_high
+                            / self.sample_rate)
+                            .sin(),
+                    ));
                     self.phase_high += 1.0;
                 }
-                self.phase_high = self.phase_high % (self.sample_rate / self.freq_low);
+                self.phase_high =
+                    self.phase_high % (self.sample_rate / self.freq_high);
+            } else {
+                // this keeps happening
+                unreachable!("FSK bit math returned a value that isn't 0 or 1");
             }
         }
         //trace!("FSK calculations turned up {:?}", &out);
         out
     }
+
+    fn idle(&mut self) -> [PcmSample; 8] {
+        const INIT_VALUE: PcmSample = PcmSample::F64(0.0);
+        let mut out: [PcmSample; 8] = [INIT_VALUE; 8];
+        for i in 0..=7 {
+            out[i] = PcmSample::F64(
+                (self.phase_low * TAU * self.freq_low/ self.sample_rate).sin()
+            );
+            self.phase_low += 1.0;
+        }
+        self.phase_low = self.phase_low % (self.sample_rate / self.freq_low);
+        out
+    }
 }
 
 impl TwoStateCarrier {
@@ -64,6 +96,7 @@ impl TwoStateCarrier {
             phase_high: 0_f64,
         }
     }
+    // setters
     fn freq_low(mut self, freq_low: u32) {
         self.freq_low = freq_low.into();
     }
diff --git a/src/dsp_common/mod.rs b/src/dsp_common/mod.rs
index 8fe1f10..16bed84 100644
--- a/src/dsp_common/mod.rs
+++ b/src/dsp_common/mod.rs
@@ -1 +1,2 @@
 pub mod carrier;
+pub mod sample;
diff --git a/src/dsp_common/sample.rs b/src/dsp_common/sample.rs
new file mode 100644
index 0000000..042cd31
--- /dev/null
+++ b/src/dsp_common/sample.rs
@@ -0,0 +1,11 @@
+#[derive(Copy)]
+pub enum PcmSample {
+    U8(u8),
+    I8(i8),
+    U16(u16),
+    I32(i32),
+    F32(f32),
+    F64(f64),
+    U64(u64),
+    I64(i64),
+}
diff --git a/src/task_msg.rs b/src/task_msg.rs
index 371f539..69e8058 100644
--- a/src/task_msg.rs
+++ b/src/task_msg.rs
@@ -1,3 +1,3 @@
-pub type PcmFrameMessage = Vec<i64>;
+pub type PcmFrameMessage = Vec<crate::dsp_common::sample::PcmSample>;
 pub type PcmSampleMessage = i64;
 pub type RawEthFrameMessage = Vec<u8>;