I've had some success with control programs done in Robot Basic
www.robotbasic.org .
the price is right, and it's designed for i/o with simple tools built-in.
Check it out.
Don
----- Original Message -----
From: "paul swed" <paulsw...@gmail.com>
To: "Discussion of precise time and frequency measurement"
<time-nuts@febo.com>
Sent: Tuesday, March 29, 2011 7:57 AM
Subject: Re: [time-nuts] WWVB Measurements using DSP recovery
Now you see I like these up to date solutions with cheap components. I
recently home brewed "YAGPSDO" yet another GPSDO, just to see how its
done.
When I look at things like a frontend and maybe a mixer thats easy stuff.
Even adding a nice A/D converter etc is easy if you can solder the darn
things.
What gets tricky is indeed the programming of the processor. I would have
to
say on the GPSDO its really not much more then a single loop pid with just
a
drop of smarts.
So back to this.
I have read the high level comments. But can we get deeper detail. Can it
be
done lets say in basic language etc. The comment I read that struck a cord
was that all you did was sample and put the information in roughly 1000
bins. Then I assume look for the bin with the most counts and called that
center frequency. Perhaps plotting that number out.
Is that really it??? Sure various filtering could also be done.
But if the above scenario were correct for me at least it gets interesting
and do-able.
By the way for definition my interest is indeed an alternate comparison
method to GPS. Kind of a second reference since we lost loran.
Having just wrapped up my project with VE2ZAZ for the HP3586 DSS its time
to
move on to the tracor 599 and wwvb.
Regards
Paul
On Tue, Mar 29, 2011 at 2:54 AM, Poul-Henning Kamp
<p...@phk.freebsd.dk>wrote:
In message <4d9129d8.4060...@comcast.net>, Greg Broburg writes:
>Can you show a circuit of what you have done?
Basically I have a 20MSPS PCI card in a PC and do it all in
software.
I did use similar principles to implement a LORAN-C receiver
in a aduc7216 (http://phk.freebsd.dk/AducLoran/) but that is
passe for US people now.
>Would you recommend the 7200 again or something
>else that is better suited?
The most user friendly way to do it, would be to have a small FPGA
which takes data from the ADC and averages it into a small piece
of multiplext or dual port RAM, and a microcontroller (ARM ?) on
the other port, doing all the high level stuff.
That way there is no real-time component to deal with in the
programming, and anybody should be able to play with the code.
The alternative is to use a DSP to read the ADC, do the
averaging and perform the high level functions. That would
be a lot harder to program for most people.
The ADC could be 16 bits, and run directly from a house standard
of 5 or 10 MHz (looks like that would cost $4 from analog.com, isn't
this future amazing ?)
Add a high resolution DAC for steering OCXO's and a serial port
or USB interface and we're done...
--
Poul-Henning Kamp | UNIX since Zilog Zeus 3.20
p...@freebsd.org | TCP/IP since RFC 956
FreeBSD committer | BSD since 4.3-tahoe
Never attribute to malice what can adequately be explained by
incompetence.
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