On Sun, 4 Dec 2016 17:07:53 -0800
jimlux wrote:
> > Wouldn't it be better to use a ferrite bead instead, for this application?
> > The much lower series capacitance and thus higher self-resonance frequency
> > should help damping the spurs.
> >
> sure, if you can get enough L. The other thing is
Hi
I’d bet it’s an inventory label put on by their customer. If so a good bet
would be something
like China Unicom.
Bob
> On Dec 4, 2016, at 5:50 PM, Larry McDavid wrote:
>
> Does anyone know the origin of the "UCCM" designation for the Trimble GPSDO
> boards recently popular here?
>
> Is
Attila - I certainly do not differentiate between "ferrite bead" and "single
turn toroidal choke".
I think the SMT inductor manufacturers think of them in the same bucket too.
what I think of as a "ferrite core for winding a multi turn inductor on", is
invariably listed as a "ferrite bead" in t
Hi
The BLM18 gives you 300 ohms at zero current. It’s impedance at
zero current per the data sheet. If you look at other parts of similar
size, the impedance drops to nearly zero at the “rated current”. Great
if you have a signal lead and no current. Not so great if you have an
OCXO that is pull
Not impressed with the PCB layout, could have been much better. Input cap is
too far from regulator, connected to ground via longish (inductive) skinny
trace. Input might benefit from simple PI filter to reduce input ripple
current. Output caps should each have their own via, maybe even two each
In my experience the term ferrite bead is used more loosely today. Most "beads"
that I've designed with were 100% machine placeable surface mount parts from
smallish 0402 chips on up to 10A rated honkers. Admittedly any tubular "bead on
wire" is not machine placeable in a surface mount oriented
On 12/5/2016 12:00 PM, time-nuts-requ...@febo.com wrote:
This is exactly the PWM to PFM mode switch I described earlier.
The 850mA are probably high enough that the DC/DC converter works
in PWM mode, thus switching with a constant frequency, even if the
load changes. On the other hand 200mA of
Depending on the application, another possible application is to
sync up the DC/DC converter to the "main" clock source. This makes
the switching noise then coherent to the system, which either makes
it average out completely, or possible to filter it out in the digital
domain using a deep notc
The UCCM modules came from Samsung WiMAX radio systems. It looks like
they OEM'd the boards from both Trimble and Symmetricom. "UCCM =
Universal Core Clock Module" UCCM-P = "Universal Core Clock Module -
Plus". I managed to find a system description document that mentions it
two or three ti
On 12/5/16 9:13 AM, Dan Kemppainen wrote:
Depending on the application, another possible application is to
sync up the DC/DC converter to the "main" clock source. This makes
the switching noise then coherent to the system, which either makes
it average out completely, or possible to filter it
FWIW, you can snub the switch node to dampen parasitic ringing in exchange
of a loss in efficiency of a couple percent. I'm pretty sure I have seen
this outlined in a few app notes.
On Mon, Dec 5, 2016 at 1:22 PM, jimlux wrote:
> On 12/5/16 9:13 AM, Dan Kemppainen wrote:
>
>>
>>
>>> Depending on
I was trying to guess what acronym (or backronym) UCCM might stand for.
Then I did an E-bay search and found all the PC boards with "94V-0" in
their part numbers for sale E-bay. Ha! Literally thousands of hits.
Tim N3QE
On Mon, Dec 5, 2016 at 7:42 AM, Bob Camp wrote:
> Hi
>
> I’d bet it’s an in
94V-0 is a UL flame retardancy test, if I recall correctly.
Sent from my iPhone
> On Dec 5, 2016, at 12:34, Tim Shoppa wrote:
>
> I was trying to guess what acronym (or backronym) UCCM might stand for.
> Then I did an E-bay search and found all the PC boards with "94V-0" in
> their part number
This will be showing up in the popular press.
Zero dead time Ytterbium lattice clock, PR release:
"NIST Debuts Dual Atomic Clock - and a New Stability Record"
https://www.nist.gov/news-events/news/2016/11/nist-debuts-dual-atomic-clock-and-new-stability-record
Nature article (paywall, $3
Yes.
-Original Message-
From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Glen Hoag
Sent: Monday, December 5, 2016 12:14 PM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] UCCM GPSDO
94V-0 is a UL flame retardancy test, if I recall correctl
Almost every PC Board made in the last few decades is UL 94V-0.
John K1AE
-Original Message-
From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Van Horn, David
Sent: Monday, December 05, 2016 3:35 PM
To: Discussion of precise time and frequency measurement
Subject: Re: [time
Well, that actually helped a little. I dug a little further into the system
documentation, and while there is only a smattering of information on the UCCM
itself, I was able to find that the alarm parameters for them dictate a
5.2-5.8v supply range, so THAT finally definitively answers one of th
17 matches
Mail list logo