OK I am use to traditional fsk that typically had a far wide shift then the
baud.
What you say would match what the tracor book says and the system is
designed for.
I still do not see why if I offset the LO to -150 hz I get a useful display
to judge timing. I am using the lissajous method.
Regards
Hi
Remember that one model for FSK is a pair of AM signals that “just happen” to
represent an FSK waveform. With normal FSK if you tune to one side, you will
get a nice AM carrier and sidebands. With MSK it’s a bit more complex since
they to do some cute stuff to cut down the bandwidth. It’s
: Saturday, September 13, 2014 6:18 PM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] NAA experiments as a reference
Thats what I am trying to understand. How good is good. Is it a useful
replacement for wwvb. Certainly kicks butt in signal strength.
Regards
Paul
WB8TSL
On 9/14/14, 8:23 AM, Bob Camp wrote:
Hi
Remember that one model for FSK is a pair of AM signals that “just
happen” to represent an FSK waveform. With normal FSK if you tune to
one side, you will get a nice AM carrier and sidebands. With MSK it’s
a bit more complex since they to do some cute
On Sun, Sep 14, 2014 at 10:20:48AM -0400, paul swed wrote:
I still do not see why if I offset the LO to -150 hz I get a useful display
to judge timing. I am using the lissajous method.
Consider that with the LO offset 150 Hz you will have a 100 Hz
beat note with the mark tone and a 200
David thanks what you say seems to be true. I could see the stable 100 Hz
and the 200 Hz was a typical 2 X lissajuo pattern within the 100 Hz pattern.
From your comments then I speculate the following from Tracor.
They used a LO 100 Hz below because the synthesizer was reasonable to
build. Adding
Paul wrote:
OK have been experimenting with a simple vlf receiver for 24 Khz.
Using an HP 3335a as the LO. The Tracor 900 d-msk-r
circuit. * * * I was hoping to see a 100 Hz somewhat steady
signal in phase relationship to my local 100 Hz reference. Thats
absolutely not apparent. Sorry
Charles I literally just sat down to do some math. What you say is the same
thoughts I have. The information I have on NAA says that for 200bit msk its
a total of a 100 hz shift +/-50 Hz. That makes no sense I would think it
would be at least +/- 100 Hz. They had in the past run a 100 bit msk. I
On 9/13/14, 7:33 AM, paul swed wrote:
Charles I literally just sat down to do some math. What you say is the same
thoughts I have. The information I have on NAA says that for 200bit msk its
a total of a 100 hz shift +/-50 Hz. That makes no sense I would think it
would be at least +/- 100 Hz.
The underlying NAA reference is UTC(USNO). How close they track it
I don't know.
--
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
Thats what I am trying to understand. How good is good. Is it a useful
replacement for wwvb. Certainly kicks butt in signal strength.
Regards
Paul
WB8TSL
On Sat, Sep 13, 2014 at 2:03 PM, Poul-Henning Kamp p...@phk.freebsd.dk
wrote:
The underlying NAA reference is UTC(USNO). How
Well it doesn't make any sense but by using a LO of + or-150hz I do get a
stable signal that at least allows me to get a sense of the stability of
the carrier. I am not using the tracor d-msk-r to see this. In fact I need
to relook at it may have an issue it does not seem to be doubling.
A big
On 9/13/14, 7:13 PM, paul swed wrote:
If NAA is transmitting 200 baud then I would expect the MSK carrier to be
+/- 100 Hz. Not +/-50 Hz.
I'd expect the total shift to be half the baud rate: 100 Hz..
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OK have been experimenting with a simple vlf receiver for 24 Khz. Using an
HP 3335a as the LO. The Tracor 900 d-msk-r circuit.
I have checked several different ways with locally locked sig gens and such
to insure that something was not running loose locally and I simply do not
see a coherent
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