diff --git a/utilities/at32f421_freertos_demo/src/TaskLoop.c b/utilities/at32f421_freertos_demo/src/TaskLoop.c
index afbe2d1..a8bc9d6 100644
--- a/utilities/at32f421_freertos_demo/src/TaskLoop.c
+++ b/utilities/at32f421_freertos_demo/src/TaskLoop.c
@@ -48,6 +48,7 @@ uint16_t g_origin_freeze_tick = 0;     // V4.36.26/32: 释放后 Origin 全冻
 uint16_t g_origin_lowlearn_tick = 0;    // V4.36.32: 冻结后降权低速补偿计数 (2s, 残余低值降权学入)
 uint16_t g_rel_band_cnt = 0;            // V4.36.30: 低Q 环带超时兜底计数 (离开触发深度持续 2.5s → 强制释放)
 uint32_t g_vacuum_ema = 0;              // V4.36.31: 真空 EMA 基线 (B3: 释放/触发参考与锚错 Origin 解耦)
+static int32_t  g_vac_frac   = 0;    // V4.37(D): EMA 余数累加器 (消 ±127 counts 整数死区)
 uint16_t g_ready_hold_tick = 0;          // V4.36.36: 判稳后就绪巩固期计数 (5ms tick, poll_green_led 递减; 按 Q 档置 5s/7s/10s)
 uint32_t loop1_Origin;
 uint32_t loop1_ORG_SUM;
@@ -562,6 +563,7 @@ void INIT_VD(void)
     g_origin_freeze_tick = 0; /* V4.36.26: 释放冻结计数清零 */
     g_rel_band_cnt = 0;      /* V4.36.30: 环带兜底计数清零 */
     g_vacuum_ema   = 0;      /* V4.36.31: 真空 EMA 清零 (判稳后重建) */
+    g_vac_frac     = 0;      /* V4.37(D): 余数累加器同步清零 */
     g_ready_hold_tick = 0;   /* V4.36.36: 就绪巩固期清零 (重建判稳时会再置) */
     g_origin_lowlearn_tick = 0;  /* V4.36.32: 降权期计数清零 */
     loop1_CAP_OK    = 0;
@@ -1244,6 +1246,7 @@ void vd1_task(void)
             g_stable_cnt  = 0;       // 计数退出时清零: 二次稳定期(安全复位)从零开始
             g_settle_cnt  = 0;
             g_vacuum_ema = loop1_Origin;   /* V4.36.31: 判稳完成建立真空基线 */
+            g_vac_frac   = 0;             /* V4.37(D): 余数累加器同步清零 */
             /* V4.36.36: 就绪巩固期按 Q 分档 (高Q 5s/中Q 7s/低Q 10s) — 绿灯继续慢闪期间系统收敛 */
             {
                 uint32_t _f0 = calc_freq_khz(loop1_Origin, loop1_LPCNT);
@@ -1315,10 +1318,18 @@ void vd1_task(void)
                         int32_t _ema_lim = (int32_t)(loop1_dlt_ORG * 3);
                         if (_ema_d > _ema_lim)  _ema_d = _ema_lim;
                         else if (_ema_d < -_ema_lim) _ema_d = -_ema_lim;
-                        if (_ema_d != 0)
+                        if (_ema_d != 0) {
                             /* V4.36.35: cast 顺序修复 — (uint32_t)负值/128 = +3355万/样本(爆炸源!)
                              * 必须 有符号先除: -10/128=0, -200/128=-1(wrap 减) — 20260908 实锤根因 */
-                            g_vacuum_ema += (uint32_t)(_ema_d / VACUUM_EMA_ALFA);
+                            /* V4.37(D): 余数累加 —— d/128 整数截断有 ±127 counts 死区
+                             * (|d|<128 步进=0 ⇒ EMA 常驻真空下方 ~127 counts ⇒ vac_ref 被拉低
+                             *  ⇒ 进入线偏低 ⇒ 触发高度漂移, 只能断电上电复位; 2026-09-11 单测实测 127) */
+                            g_vac_frac += _ema_d;
+                            {   int32_t _st = g_vac_frac / VACUUM_EMA_ALFA;
+                                g_vac_frac -= _st * VACUUM_EMA_ALFA;
+                                g_vacuum_ema += (uint32_t)_st;
+                            }
+                        }
                         if (((int32_t)loop1_Origin - (int32_t)g_vacuum_ema) > (int32_t)(loop1_Origin >> 2) ||
                             ((int32_t)g_vacuum_ema - (int32_t)loop1_Origin) > (int32_t)(loop1_Origin >> 2))
                             g_vacuum_ema = loop1_Origin;