Excellent. This may be one of the factors that gave the Triton IV through
the Corsair a reputation for fast QSK. Every millisecond counts! Now I
will need to re-modify my Omni C for the original sidetone and add the
filtering. Also, I will check to see where the sidetone triggering
originates. I believe it's the T voltage which is a product of some
timing components from the key line. If so, there may be another
opportunity to reduce delay. Trying to run a paddle at 40wpm isn't easy
and eliminating that sidetone delay will certainly help.
Of course, the type of keyer will have a huge bearing on this delay. I
use an old MFJ with the Curtis 8044 chip. I'm not sure what the delay is
between key closure and output nor have I ever heard this discussed but
it needs to be investigated.
Some guys use the sidetone in their keyers which is fine if you are using
a speaker but I like using my headphones at times. And of course, there
is a delay between the speaker and the ear :*)
-----Original Message-----
From: "Dr. Gerald N. Johnson, electrical engineer" <geraldj@isunet.net>
To: n4lq@iglou.com
To: <tentec@contesting.com>
Date: Mon, 15 Apr 2002 10:23:41 -0500
Subject: Re: [TenTec] Sidetone revisited
> The filtered sawtooth will always have the least delay. The filter can
> be a simple two or three pole low pass. The effect of the twin T is to
> make a narrow bandpass filter and its high Q in the feedback position
> of
> an op amp makes its output slow to change.
>
> If there's lots of signal from the sawtooth, a simple RC filter which
> looses amplitude rapidly with the increasing stages can clean the
> sawtooth adequately. No need for high Q components from either
> inductors
> or the feedback of an op amp.
>
> 73, Jerry, K0CQ
> --
> Entire content copyright Dr. Gerald N. Johnson. Reproduction by
> permission only.
>
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