r5720 - trunk/gta02-core/docs/ecn

[werner at docs.openmoko.org]

Author: werner
Date: 2009-11-29 19:51:43 +0100 (Sun, 29 Nov 2009)
New Revision: 5720

Added:
   trunk/gta02-core/docs/ecn/ecn0043.txt
Modified:
   trunk/gta02-core/docs/ecn/STATUS
   trunk/gta02-core/docs/ecn/ecn0038.txt
Log:
- ECN0038: added review tag
- ECN0043: new ECN for assorted audio cleanup



Modified: trunk/gta02-core/docs/ecn/STATUS
===================================================================
--- trunk/gta02-core/docs/ecn/STATUS	2009-11-28 20:27:44 UTC (rev 5719)
+++ trunk/gta02-core/docs/ecn/STATUS	2009-11-29 18:51:43 UTC (rev 5720)
@@ -42,6 +42,7 @@
 0040	Discuss	Remove backup battery (BAT1701)
 0041	Discuss	Test points and 0R resistors for camera interface
 0042	Discuss	Changing internal microphone to symmetrical configuration
+0043	Discuss	Assorted audio cleanup
 
 
 Open ECNs
@@ -63,4 +64,4 @@
 0040	PMU, MODEM
 0041	CPU
 0042    AUDIO
-
+0043	AUDIO

Modified: trunk/gta02-core/docs/ecn/ecn0038.txt
===================================================================
--- trunk/gta02-core/docs/ecn/ecn0038.txt	2009-11-28 20:27:44 UTC (rev 5719)
+++ trunk/gta02-core/docs/ecn/ecn0038.txt	2009-11-29 18:51:43 UTC (rev 5720)
@@ -17,3 +17,4 @@
 Author: Rene Harder <rehar at saweb.de> 
 Review: Werner Almesberger <werner at openmoko.org>, SVN 5690
 Commit: SVN 5718
+Review: Werner Almesberger <werner at openmoko.org>, SVN 5719

Added: trunk/gta02-core/docs/ecn/ecn0043.txt
===================================================================
--- trunk/gta02-core/docs/ecn/ecn0043.txt	                        (rev 0)
+++ trunk/gta02-core/docs/ecn/ecn0043.txt	2009-11-29 18:51:43 UTC (rev 5720)
@@ -0,0 +1,18 @@
+Assorted audio cleanup
+
+
+A number of components are leftovers from earlier designs and experiments,
+and don't serve a purpose anymore. We can thus safely remove them.
+
+They are:
+
+- C4307: unlike the "buzzfix" capacitor C4306 that stabilizes MICBIAS in
+  the presence of interferences, the filter capacitor on MIC2 (C4307)
+  serves no purpose
+
+- R3004 and R3005: since we don't perceive a need to cut off the speaker,
+  these 0R resistors in the speaker audio path serve no real purpose and
+  should be removed
+
+
+Author: Werner Almesberger <werner at openmoko.org>