diff --git a/content/signal_processing/algorithm/EMD/basic.md b/content/signal_processing/algorithm/EMD/basic.md
index 6f71df0a0..6a6d6b98b 100644
--- a/content/signal_processing/algorithm/EMD/basic.md
+++ b/content/signal_processing/algorithm/EMD/basic.md
@@ -7,7 +7,7 @@ tags:
   - signal
   - algorithm
   - math
-date: 2024-04-17
+date: 2024-04-24
 ---
 # Introduction
 
diff --git a/content/signal_processing/algorithm/advanced_statistic/autocorrelation/period_detection.md b/content/signal_processing/algorithm/advanced_statistic/autocorrelation/period_detection.md
index 0419fad36..ac3fdc9f0 100644
--- a/content/signal_processing/algorithm/advanced_statistic/autocorrelation/period_detection.md
+++ b/content/signal_processing/algorithm/advanced_statistic/autocorrelation/period_detection.md
@@ -3,6 +3,7 @@ title: Period Detection by Autocorrelation
 tags:
   - signal
   - signal-processing
+date: 2024-04-17
 ---
 
 
diff --git a/content/signal_processing/basic_knowledge/concept/linear.md b/content/signal_processing/basic_knowledge/concept/linear.md
index c0c512726..78ee6ef31 100644
--- a/content/signal_processing/basic_knowledge/concept/linear.md
+++ b/content/signal_processing/basic_knowledge/concept/linear.md
@@ -4,6 +4,7 @@ tags:
   - basic
   - signal
   - signal-processing
+date: 2024-04-17
 ---
 
 有一个系统$\mathcal{F}$,