Leo is right
Depends on the application. Phase lock for 1pps to trigger say,
simultaneous capture of many radio telescopes around the globe is a good
need for phase lock to a source. Frequency lock might suit many . change
of phase between two sources might indicate frequency change, or duty
stability <= 1e-12
glen
On 7/07/2019 6:56 PM, Achim Gratz wrote:
Glen English VK1XX writes:
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RRR . you are right about drop and noise..
For others not familiar with this behaviour, one thing when looking is
PSRR etc on LDOs..take a good look at this value VERSUS dropout /
headroom . Most devices are in the toilet when dropout is nigh... In my
SDRs I (used) to run 2V around for 1.8V
with regard to phase angle and confusion over load and power flow ...
I think people getting confused with the phase of measured current to
the voltage .
the voltage phase is fixed, and should be consistent . when you measure
the current phase, relatve to the voltage, that tells you about
OK so I have the NGOCOMM program for the E1938A.
I see looking at the DLLs it was written in Borland OWL.
Does anyone have the C++ source code, or know what is in it ,
and also does anyone know exactly what is in the E2PROM?
all this for extending the MAINTAINABLE life of these excellent
This sounds like a shield is not connected , or broken on one of the
distribution cables.
The 10 MHz will not appreciably leak from half decent coax properly
terminated.
The 10 MHz should not be detectable unless a wire is coupled directly on
the coax braid.
That assumes the 10 MHz source
Bob, thanks for the info. I will immerse myself in the archives.
regards,
glen.
VK1XX / AI6UM
On 1/07/2019 11:15 PM, Bob kb8tq wrote:
Hi
There are a lot of posts back in the archives about various things on Cs
standards.
Beam current is probably the best way to see
Hi Bob
RRR.
In fact all my original GPSDOs in the '90s were FLLs, for radio comms
gear, essentially frequency counters with the error driving a PI loop.
They were controlling standard XOs. For new engineers, if they want a
project to teach them many skills, I recommend a GPSDO project from
.
I of course need the Rm number to acurately model loss.
73
glen english
VK1XX
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On Sep 18, 2019, at 2:35 PM, Glen English VK1XX
wrote:
I wonder if anyone can shed any light on this question, since this forum is
loaded with those who REALLY understand crystals.
I am modeling crystal filters (VHF) in SPICE. There are some specific acoustic
mode models for SPICE in some Post
well. thank you everyone for your contributions !
I had a good night in reading the references.
I agree the cascaded band-limited limiter strategy is eminently suitable.
That LT part looks like an excellent option, of course,
horses-for-courses caveat applies for freqs and risetimes...
On
OK research people...since this forum is loaded with bleeding edge
understanding, Is there such a thing in the lab as a material that can
store, in a 2 level (1 bit) format (or more) , a discrete time
representation of some event ?
In my simple example (dream), an arrangement of some
thanks all for the interesting answers on that one.
and the notes on ZCDs was most useful.
On 29/07/2019
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Hi
there is quite a bit done in this area of FPGAs, IDELAYS etc for this
application. and also quite a bit written already on TIMENUTS I find
from archives.
From my POV, the pressure on the design is the input circuitry...My gut
is to start with a ADCMP572 and drive several FPGA pins with
I'm currently getting schematics together for just such a box, to be
open source etc. maybe it can be a TAPR project I dunno.
I'll release round 1 schematics shortly.
Most of my ZCD work to this point usually uses LVDS receivers either
discrete or FPGA IOBUF
and more lately the ADCMP572
Anyone had a play with this device ? 1pps (or whatever) input,
http://www.ti.com/lit/ds/symlink/lmk05318.pdf
For those with a radio interest, or telecom interest..
I will order an eval board and see what its like...
Yeah, I know its easy to do with a micro or fpga , but the phase noise
from
So, is there anytime once a year or two years where members of this
group get together ?
I guess many of the professionals here go to their own respective
industry meetings . Like we all do.
Rub shoulders with Rubiola etc.
glen
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The F9T and F9P - are these interchangeable for stationary timing use
and stationary high performance position ?
From how I read the datasheets, :
>>the F9P has an internal RTK engine, and the F9T outputs the info RTCM
etc and that data can be run on a external RTK engine on a micro.
The P
Roy,
The passive frequency doubler is essentially perfect. It will add some
flicker noise. (There are documented methods like using CB connected
transistors etc however I suggest just build it unless you are after
doing better than the best labs in the world).
For all passive freq doublers,
running at
the time.
If you are trying to do some sort of master / slave setup, it’s best to dive
into just what is involved with
that task. For a system where both master and slave are mobile, the P is likely
the better choice.
Bob
On Jul 17, 2019, at 4:57 PM, Glen English VK1XX
wrote:
The F9T
good info Rick
ROY - I have spiced up in LTSPICE a doubler and 4 harmonics which you
can vary the amplitudes of the harmonics in the current sources I1, I2,
I3, I4. There is a basic tank circuit on the output which you can
connect/ disconnect etc.
www.cortexrf.com.au/5_meg_doubler.asc
Bernd, thanks for the excellent treatment on the subject
glen
On 21/09/2019 4:42 PM, Bernd Neubig wrote:
Hi,
There is nothing like a fixed ratio between R1 at 3rd or 5th overtone the R1
at fundamental mode. The best approach through C1 and Q.
C1 reduces with the square of overtone N (for
Bob, are there any URLs you can point to, or provide advice on, if
inspecting a Cesium for sale, is there an hour counter, or other metrics
that can be measured in the tube department ? (I am familiar with TWTs,
Klystrons etc so the HV doesnt bother me) in order to ascertain the
level of life
. The opamp was
chopper stabilized and I ensured the op amp never operated in the
crossover region of the opamp output driver. These were on AT cuts at
97 deg C ...
cheers
Glen. AI6UM / VK1XX
On 6/07/2019 2:37 PM, Richard (Rick) Karlquist wrote:
On 7/5/2019 8:20 PM, Glen English VK1XX
Has anyone got this , is the PIC read data prohibited ?
Is it still a closely guarded secret?, there were some very clever and
novel ideas used in that slab, in my opinion.
Glen
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Hi Rob
Thanks for the post. wow. OK thanks for the notes.
No expense spared anywhere on the quality of those parts used.
mine are Rev Bs
EEPROM. might need to read out that info while it is good.
Probably important parameters
what goes wrong with these babies ? or should I consult
In Australia, we have a national grid. It's big.
National meaning all but a few isolated towns like Darwin, Perth. Perth
might be connected via a 1800 km HVDC line in the future... which is a
different story DC interconnectors
So, I gather someone with their MASER in Adelaide
Hal, Good point.
and I have never seen a spec for phase stability for Cat-7 cable !
for RG58, OR OTHER polyethylene, might be up to 150ppm /deg C. maybe as
good as 10 ppm/deg C for some LMR.
With 1000 feet of cable might be an issue for fine stuff. a few nano
seconds each way over
for causing confusion.
---
(Mr.) Taka Kamiya
KB4EMF / ex JF2DKG
On Sunday, July 7, 2019, 12:00:52 AM EDT, Glen English VK1XX
wrote:
Hal, Good point.
and I have never seen a spec for phase stability for Cat-7 cable !
for RG58, OR OTHER
I thoroughly agree with Bob.
Suggest converting 1pps into something hardy like LVDS or LVPECL and
using twisted pair , Cat 7 (individually shielded pairs and controlled
skew cable) , or a pair of coax (balanced coax). The balanced signals
will deal with the chance of power supply
thanks Corby, and all, for their beam tube buying advice.
On 7/07/2019 4:34 AM, cdel...@juno.com wrote:
When evaluating an instrument with a used tube the beam current is not
the best indicator to look at!
For an HP instrument If the tube label has the EM voltage listed then
with the beam
OK, good info, thanks.
Well I have bought 7 x E1938As, with the intention of building a better
GPSDO.
My interest in the E1938A firmware hex was if I had to replace any of
the PICs at sometime in the future.
My intention is to use the average of multiple stationary mode GPS 1PPS
signals
functionality, you'd probably be better off training a
logistic classifier, and using it instead. That said, both methods would be
overkill, imo- I'd use a PID instead.
Best,
Chase
On Tue, Jul 9, 2019 at 10:00 PM Glen English VK1XX <
glenl...@pacificmedia.com.au> wrote:
Has anyone tried to use a
and non monitonicity in the device is the death of a control loops.
My attempts at building good OCXOs using cheap AT crystals in the 90s
was thwarted by non monotonic bending crystals !
And everytime they would wake up, the monitonicity would be in a
different part of the control
Has anyone tried to use a Neural net to control oven tmep, rather than
the ye olde PID ?
IE the algorithm learns from previous beheviour and successfully
predicts behaviour (or not).
I'm sure there are a few out there proficient with machine learning
algorithms.
Might make a good masters
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