From 80055076b8b6af141543f466b45c9e29c0bf3b1d Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Robert=20J=C3=B6rdens?= <rj@quartiq.de>
Date: Sun, 31 Jan 2021 17:41:20 +0100
Subject: [PATCH] lockin: scale output

---
 src/bin/lockin.rs | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/src/bin/lockin.rs b/src/bin/lockin.rs
index 48c717a..f9e2f58 100644
--- a/src/bin/lockin.rs
+++ b/src/bin/lockin.rs
@@ -151,16 +151,14 @@ const APP: () = {
                 phase = iir_ch[1][j].update(&mut iir_state[1][j], phase);
             }
 
-            // TODO: IIR filter DC gain needs to be 1/(1 << 16)
-
             // Note(unsafe): range clipping to i16 is ensured by IIR filters above.
             // Convert to DAC data.
             for i in 0..dac_samples[0].len() {
                 unsafe {
                     dac_samples[0][i] =
-                        power.to_int_unchecked::<i16>() as u16 ^ 0x8000;
+                        (power.to_int_unchecked::<i32>() >> 16) as u16 ^ 0x8000;
                     dac_samples[1][i] =
-                        phase.to_int_unchecked::<i16>() as u16 ^ 0x8000;
+                        (phase.to_int_unchecked::<i32>() >> 16) as u16 ^ 0x8000;
                 }
             }
         }