RTTY
[Top] [All Lists]

Re: [RTTY] Multipath, testing, soundcards

To: <RTTY@contesting.com>
Subject: Re: [RTTY] Multipath, testing, soundcards
From: Bill Turner <wrt@dslextreme.com>
Reply-to: wrt@dslextreme.com
Date: Thu, 22 Apr 2004 08:18:53 -0700
List-post: <mailto:rtty@contesting.com>
On Thu, 22 Apr 2004 09:57:32 -0500, Tom McDermott wrote:

>A repeating
>pattern (specifically:  RYRYRYRY...) is the worst possible pattern to
>utilize for such test. The pattern should have the most random-like pattern
>of bits. This is because badly-designed modem filters can pass the repeating
>pattern test with good results, yet yield poor copy with more random
>characters.

_________________________________________________________

Could you please explain this further?  It would seem to me that a
filter which only processes one bit at a time would have no *knowledge*
of what came before or what follows afterwards, and therefore would not
be capable of recognizing whether a pattern was repeating or not.  In
other words, would MARK MARK MARK MARK be processed differently than
MARK SPACE MARK SPACE?  Perhaps you are saying that a poorly designed
filter would not handle the transition from MARK to SPACE correctly?

Either way, this could be proven empirically pretty easily I would
think.  

--
Bill, W6WRT
QSLs via LoTW

_______________________________________________
RTTY mailing list
RTTY@contesting.com
http://lists.contesting.com/mailman/listinfo/rtty

<Prev in Thread] Current Thread [Next in Thread>