Hi Bob,
You say you are not ready to go GPS. I assume you mean a GPSDO. If you have a
'scope you can use just about any GPS with a 1pps output. trigger the scope
from the 1pps while monitoring the 20MHz sine wave and adjust for minimum drift
of the trace. A timing GPS module will be better (you
Thanks for all your thoughts on the subject. Let me play back what I
have learned and how it may apply to my challenge. One of my first
applications is to use a 10MHz output to phaselock a VCXO master clock
in a radio transceiver. The VCXO is the Christek CVHD-950 which has a
noise floor of
I've had the Rb on the shelf for a few days next to a few old 3.5" disk drives,
and it suddenly struck me that they're about the same size. External drive
cases and PSUs are "cheap as chips", as they say, so I was wondering how many
people are using an external drive case to hold their Rb stand
Hi Bob,
If you've got a stable SSB receiver and an AM receiver capable of 20MHz, here's
a trick to get an accurate beat: Tune both to WWV, and listen to the WWV
generated tone. Adjust the frequency on your SSB receiver to exactly beat the
tone on the AM receiver. That way, you're matching a
Hi,
Square wave outputs can be rather higher maintainance, with the whole
distribution system from the PCB design and layout through all the wiring to
the terminations and beyond all has to be up to the fast IC's/transitions.
10MHz sine waves are much more forgiving.
Square waves are useful fo
This is off topic but I'm unsure how to do it properly.
I am trying to 'discipline' a couple of sources. I zero beat with 20 MHz WWV
but can't tell the difference between fading and the beat, so I am stuck in the
vicinity of 1 Hz possible error. That's 50 ppb I think.
What can I do to take th
Hi Bob,
I should have mentioned that I added a new 5MHz output, and the coax ran within
1/8" of the single DAC wire going to the OCXO. I don't think anything else
changed, but of course there could be some flake of something on the DAC line
that I missed. I put on the RG-174 and I see that it
Hi
I suspect that you have a ground offset between the OCXO's ground return and
the DAC's ground reference. The signal *should* be DC, Shielding it won't hurt,
but it really should not help much. If anything is an issue a simple R/C
filter at the OCXO pin should nuke it better than coax will.
I made some minor hardware changes to my GPSDO today and I see that it's locked
to a new DAC voltage about 21mV higher. So, I was wondering about shielding
the short run to the OCXO. I have immediately available RG-174 and I'm putting
that in. But, should this be some sort of steel shelled se
Hi
Ok, the SN74LVC1G125 is 35 cents each at Mouser if you buy at least 10 pieces.
That's going to be $3.50. LM78L05 is 26.5 cents if you buy 10 pcs. You will
need some bypass caps and resistors, I'd assume you already have them.
Say you want 10 channels, that's 11 logic id's. At one IC per out
Bob,
Totally agree.
24mA of drive at 3.3V is pretty nice in a small footprint for the parts we
are discussing. Of course as you have pointed out you can drive them at 5V
too.
Mini-circuits is a good place to look too - especially for us hobbyists:
http://www.minicircuits.com/products/DesignerK
Hi
How clean is your clock source? If you have something that is -150 dbc at 1 Hz,
then you probably need some fancy analog gizmos. If you can make do with "only"
-110 to -120 dbc/Hz at 1 Hz, then properly driven LVC CMOS will do just fine.
That's true for a square or a sine output. Since you p
Tom,
If you are building your own board - I have used this part:
SN74LVC1G125 - Single Bus Buffer Gate with 3-State Output
and it is suitable for the job. I have measured the performance of the
logic family - and what I observed follows what is in the spec sheets from
TI. I did not officially
TV video distribution amps work very nicely. Even better if you open them
up and change the matching from 75ohm to 50. :)
Bob
On Thu, Sep 26, 2013 at 3:19 PM, Glenn Little WB4UIV <
glennmaill...@bellsouth.net> wrote:
> Would an analog video distribution amplifier work?
> These are available ch
Would an analog video distribution amplifier work?
These are available cheap.
TV stations used these eight or so in a frame.
The frame had a power supply and the BNC i/o connectors.
Each da would drive 6 or 8 outputs.
73
Glenn
WB4UIV
Retired TV CE.
At 01:28 PM 9/26/2013, you wrote:
I am looking
It seems you would need to think of the Pulsar as the clock behind the GPS sat.
You then have an algorithm to add the other need information at the rec end. To
make things easier add to the constellation one master clock signal with
corrections and other needed info from earth.
Thomas Knox
For low phase noise output at lower frequencies you should consider a
lambda divider feeding a low pass filter.
Although wideband opamps are convenient a discrete buffer amp can
produce a higher level output with lower additive phase noisee.
Bruce
Tom Minnis wrote:
I am looking into various de
I am looking into various degrees of craziness. The source is CMOS and
there are plenty of 1 in to N out parts designed to drive clocks on a
PCB but not much is said about driving clocks on to a random length of
coax to another piece of equipment and what additional precautions that
might warr
Interesting-Don
http://www.rdmag.com/news/2013/09/spirals-light-may-lead-better-electronics?
et_cid=3503053&et_rid=537232301&type=headline
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Hi
Standard high speed CMOS logic works pretty well. How crazy are you trying to
get?
Bob
On Sep 26, 2013, at 1:48 AM, Tom Minnis wrote:
> I am working on a small clock distributor and wanted to get some ideas on
> what works best for 10MHz and 1PPS driver circuits. I remember sifting
> th
On Thu, Sep 26, 2013 at 3:59 PM, REEVES Paul wrote:
> Some of them might be... you could certainly speculate that any
> culture that has attained sufficient technology to make interstellar travel
> possible (and need navigation beacons) would probably have sufficient power
> to 'engineer' th
If there is Alien life on this planet they are most assuredly Time-Nuts.
Thomas Knox
> From: paul.ree...@uk.thalesgroup.com
> To: m...@maxsmusicplace.com; time-nuts@febo.com
> Date: Thu, 26 Sep 2013 08:59:17 +0100
> Subject: Re: [time-nuts] Pulsars make a GPS for the cosmos
>
> Some of them mi
Some of them might be... you could certainly speculate that any culture
that has attained sufficient technology to make interstellar travel possible
(and need navigation beacons) would probably have sufficient power to
'engineer' the occasional neutron star into the correct configuration.
O
Please, tell about The Phase Comparator
http://www.qsl.net/z/zl1bpu//MICRO/VNGBOX/phase.htm
Среда, 25 сентября 2013, 6:49 +12:00 от "Murray Greenman"
:
>Nick,
>Tankyou for your interest in one of my older projects. You have seen the VNG
>in a Box web page, which should give you a link to a pa
I remember when pulsars were first discovered one speculation was that they
were interstellar navigation beacons established by intelligent life forms.
Regards.
Max. K 4 O DS.
Email: m...@maxsmusicplace.com
Transistor site http://www.funwithtransistors.net
Vacuum tube site: http://www.funwit
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