GTA02 Audio issues

[Graeme Gregory]

I have been working on the problem of echo in GSM calls and I seem to
have boiled the issue down to a hardware problem. There is I think the
possibility there is a mechanical problem with the case design where
audio from the handset speaker ends up entering the handset mic far too
easily causing echos.

I suspect this issue also affects GTA01, its just no-one used that as a
phone much.

I have attached the private email thread that occurred to lead up to
this issue. It would be useful if more people had ideas.

Graeme
-------------- next part --------------
An embedded message was scrubbed...
From: Wolfgang Spraul <wolfgang at openmoko.com>
Subject: echo
Date: Sun, 2 Mar 2008 09:24:57 +0800
Size: 1942
Url: http://lists.openmoko.org/pipermail/openmoko-kernel/attachments/20080304/45f88ffb/attachment.eml 
-------------- next part --------------
An embedded message was scrubbed...
From: Wolfgang Spraul <wolfgang at openmoko.com>
Subject: Re: echo
Date: Sun, 2 Mar 2008 22:41:23 +0800
Size: 2883
Url: http://lists.openmoko.org/pipermail/openmoko-kernel/attachments/20080304/45f88ffb/attachment-0001.eml 
-------------- next part --------------
An embedded message was scrubbed...
From: Wolfgang Spraul <wolfgang at openmoko.com>
Subject: Re: echo
Date: Mon, 3 Mar 2008 11:39:00 +0800
Size: 3483
Url: http://lists.openmoko.org/pipermail/openmoko-kernel/attachments/20080304/45f88ffb/attachment-0002.eml 
-------------- next part --------------
An embedded message was scrubbed...
From: Sean Chiang <sean_chiang at openmoko.com>
Subject: Re: echo
Date: Tue, 04 Mar 2008 11:35:06 +0800
Size: 3664
Url: http://lists.openmoko.org/pipermail/openmoko-kernel/attachments/20080304/45f88ffb/attachment-0003.eml 
-------------- next part --------------
An embedded message was scrubbed...
From: John Lee <john_lee at openmoko.com>
Subject: Re: echo
Date: Tue, 4 Mar 2008 11:58:46 +0800
Size: 2396
Url: http://lists.openmoko.org/pipermail/openmoko-kernel/attachments/20080304/45f88ffb/attachment-0004.eml 
-------------- next part --------------
An embedded message was scrubbed...
From: Wolfgang Spraul <wolfgang at openmoko.com>
Subject: Re: echo
Date: Tue, 4 Mar 2008 17:55:23 +0800
Size: 2522
Url: http://lists.openmoko.org/pipermail/openmoko-kernel/attachments/20080304/45f88ffb/attachment-0005.eml 
-------------- next part --------------
An embedded message was scrubbed...
From: Wolfgang Spraul <wolfgang at openmoko.com>
Subject: Re: echo
Date: Tue, 4 Mar 2008 18:41:01 +0800
Size: 2943
Url: http://lists.openmoko.org/pipermail/openmoko-kernel/attachments/20080304/45f88ffb/attachment-0006.eml 
-------------- next part --------------
An embedded message was scrubbed...
From: Graeme Gregory <graeme at openmoko.org>
Subject: Re: echo
Date: Tue, 4 Mar 2008 11:44:21 +0000
Size: 2820
Url: http://lists.openmoko.org/pipermail/openmoko-kernel/attachments/20080304/45f88ffb/attachment-0007.eml 
-------------- next part --------------
An embedded message was scrubbed...
From: Graeme Gregory <graeme at openmoko.org>
Subject: Re: echo
Date: Tue, 4 Mar 2008 11:49:43 +0000
Size: 3120
Url: http://lists.openmoko.org/pipermail/openmoko-kernel/attachments/20080304/45f88ffb/attachment-0008.eml 
-------------- next part --------------
An embedded message was scrubbed...
From: Wolfgang Spraul <wolfgang at openmoko.com>
Subject: Re: echo
Date: Wed, 5 Mar 2008 00:35:21 +0800
Size: 3390
Url: http://lists.openmoko.org/pipermail/openmoko-kernel/attachments/20080304/45f88ffb/attachment-0009.eml