Flow-charts.md

@@ -43,7 +43,7 @@ graph TD
 
 ### Preprocessing
 
-**Processing that can be done separately on each channel**
+**Processing should be done separately on each channel**
 ```mermaid
 graph TD 
    h[(Data from channel)]
@@ -58,7 +58,8 @@ graph TD
    style F fill:#bbf,stroke:#bbf
 ```
 
-**Processing done on both channels
+### Cross correlation
+** Compute CSD and PSD as a function of time and frequency** 
 
 ```mermaid
 graph TD 
@@ -74,4 +75,21 @@ graph TD
    C-->D3[CSD]
 ```
 
+### Post processing
+
+```mermaid
+graph TD 
+   A1[PSD 1]
+   A2[PSD 2]
+   A3[CSD]
+   A1-->B(Compute sigma of f,t)
+   A2-->B
+   A3-->C(compute Y of f,t)
+   B-->|statistical checks|D(Combine segments to get Y and sigma of f)
+   C-->D
+   D-->O1[Main output]
+   D-->E(Combine frequency to get optimal estimates if needed)
+   E-->O2[Secondary output]
+```
+
 # Simulation
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