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Re: SDR-1000 (was FT-847 discontinued?)
- Subject: Re: [amsat-bb] SDR-1000 (was FT-847 discontinued?)
- From: k0vty@xxxxxxxx
- Date: Thu, 15 Dec 2005 20:01:16 CST
If I recall correctly :
Quantizing any short duration signal to digitize it must be done fast
enough to be able to
re constitute the signal again
Quantizing a CW dit requires high speed sampling .
Higher than SSB voice.
I hope I am correct on this as it has been a long time ago that
quantizing received radar pulses was an every day event.
Like you I am trying to grasp new ways and equipment idea's.
Keep trying
Joe K0VTY
============================
On Thu, 15 Dec 2005 18:46:21 -0600 "John P. Toscano"
<tosca005@tc.umn.edu> writes:
> Dave G. wrote:
>
> > The problem for high speed CW lies in the inherent delay with
> > the DSP processing algorithms. IMHO because of that delay
> > it's not yet a serious contest rig YMMV!!
>
> Dave (or anyone else on the list who knows):
>
> Is the "slow" CW speed only a function of computer-generated CW? If
> so,
> couldn't you get around that problem by using an external keyer?
> The
> MFJ-495, for example, allows you to send CW via straight key,
> paddles, a
> PC keyboard plugged directly into it, or via a serial data stream
> from a
> computer. It handles speeds up to 990 WPM (or so they say), which
> oughta be fast enough for almost anyone. :) (Heck, if I could
> reliably
> work CW at a "mere" 20 WPM I'd be ecstatic!)
>
> Or is the SDR not able to send fast CW even if it doesn't have to
> synthesize the CW from keyboard commands on the same PC that is
> supporting the digital encoding/decoding process? It just seems odd
> to
> me that it could encode voice into an SSB or AM or FM signal, but
> simple
> "on/off" sequences of Morse code would be hard for it to do... But
> I'm
> certainly very uneducated (at least so far) about the whole SDR DSP
> process, so maybe I'm way off base...
>
> If the problem is the delay between hitting the dit or dah side of
> the
> paddle and the time that you hear feedback from the monitor speaker,
> it
> should be possible to listen to yourself send only from the output
> of
> the keyer, and have the SDR not echo what you send back to your
> ears.
> Then, it doesn't matter if it takes an extra 300ms for your CW to
> finish
> transmitting before the person on the other end can respond.
>
> Or am I still missing something totally? (These are honest
> questions,
> I'm not trying to take pot shots at anyone, I really don't know the
> answers to them. Since I've been tempted to step into the SDR-1000
> world "one of these days", I'd really like to know more about it.)
>
> 73 de W0JT
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