diff --git a/src/bin/lockin-external.rs b/src/bin/lockin-external.rs
index b3b9d4f..f24f251 100644
--- a/src/bin/lockin-external.rs
+++ b/src/bin/lockin-external.rs
@@ -118,12 +118,12 @@ const APP: () = {
             .zip(Accu::new(sample_phase, sample_frequency))
             // Convert to signed, MSB align the ADC sample, update the Lockin (demodulate, filter)
             .map(|(&sample, phase)| {
-                let s = (sample as i16 as i32)
-                    << (15 - design_parameters::SAMPLE_BUFFER_SIZE_LOG2 + 1);
+                let s = (sample as i16 as i32) << (15 + 1);
                 lockin.update(s, phase, time_constant)
             })
             // Decimate
-            .sum();
+            .last()
+            .unwrap();
 
         let conf = "frequency_discriminator";
         let output = match conf {
diff --git a/src/bin/lockin-internal.rs b/src/bin/lockin-internal.rs
index 6913f0a..393130e 100644
--- a/src/bin/lockin-internal.rs
+++ b/src/bin/lockin-internal.rs
@@ -101,12 +101,12 @@ const APP: () = {
             .zip(Accu::new(sample_phase, sample_frequency))
             // Convert to signed, MSB align the ADC sample, update the Lockin (demodulate, filter)
             .map(|(&sample, phase)| {
-                let s = (sample as i16 as i32)
-                    << (15 - design_parameters::SAMPLE_BUFFER_SIZE_LOG2 + 1);
+                let s = (sample as i16 as i32) << (15 + 1);
                 lockin.update(s, phase, time_constant)
             })
             // Decimate
-            .sum();
+            .last()
+            .unwrap();
 
         for value in dac_samples[1].iter_mut() {
             *value = (output.arg() >> 16) as u16 ^ 0x8000;