On Fri, Sep 2, 2016 at 12:51 AM, Charles Steinmetz
wrote:
> Now shorten the observation time to 20nS. We see 1/5 of a complete cycle
> (72 degrees, 0.4 pi radians) of the wave. No matter which particular 72
> degrees we see, we simply don't have enough information to reliably deduce
I do not se
At my amateur radio club we have Internet access via a WiFi dongle with a Pay
As You Go card. A Windows 10 PC is only powered up while we are there, so on
around 2-4 hours per week.
Does anyone have any thoughts on what might be the most suitable software to
run on our Windows 10 PC to set the
The problem is that "frequency" has more than one meaning. The main
dictionary definitions have to do with the frequency of occurrence of
some items in a category with respect to a larger set, or the frequency
of occurrence of some repeating event per unit of time. But we also use
mathematical repr
On 9/1/16 5:51 PM, Charles Steinmetz wrote:
Nick wrote:
On a theoretical basis, can one speak of the limit of the frequency
observed as tau approaches zero?
Might that in some way be the "instantaneous frequency" which people
often think of?
That is (or is "something like") what it *would* be
Nick wrote:
On a theoretical basis, can one speak of the limit of the frequency observed as
tau approaches zero?
Might that in some way be the "instantaneous frequency" which people often
think of?
That is (or is "something like") what it *would* be, but a little
thought experiment will sho
Hi
Unfortunately if you read a typical text on FM modulation, "instantaneous
frequency" comes up pretty fast. In that context it has a valid meaning. Once
out of context, it gets you in trouble. That point is never made when the term
is introduced.
Bob
> On Sep 1, 2016, at 8:51 PM, Charles St
Bert wrote:
maybe some one smarter than us can working with the parameters that Tbolt
makes available better performance can be achieved
I am quite sure of that
the frequency is being changed to compensate for time
Yes, the PPS is steered by making slight adjustments to the OCXO
frequency
Hi
Frequency is a "change over time". If delta time is zero it is undefined. As
you observe it in shorter time periods, the accuracy / stability gets worse.
Since the error bars expand there isn't much of a limit as you go shorter. They
are not quite the same thing, but they are related.
Bob
Just a stupid question...
On a theoretical basis, can one speak of the limit of the frequency observed as
tau approaches zero?
Might that in some way be the "instantaneous frequency" which people often
think of?
I rather suspect the answer is "no," but I'll ask anyway.
Sent from my iPhone
>
Tom wrote:
No, again it sounds like you have a bad TBolt. Or something is wrong (antenna?
reception? time constant? environment? China resoldered parts?). I appreciate
that Juerg did lots of testing -- do you happen to have his ADEV plot?
Your claim of 1e-10 is order(s) of magnitude worse tha
Hi
The problem with absolute frequency is the one they ran into in the 60’s (and
before):
There is no really good way to measure it.
You certainly can take data. The data can have lots of resolution. That part
has
always been fairly easy. The problem is that the more carefully you look, th
maybe some one smarter than us can working with the parameters that Tbolt
makes available better performance can be achieved but it is a fact that
the frequency is being changed to compensate for time and Tom's frequency
data matches our's and we do not care about ADEV, we care about the actu
For us it is absolute Frequency, to me it is a measure of true performance.
In a message dated 9/1/2016 4:52:35 P.M. Eastern Daylight Time,
kb...@n1k.org writes:
Hi
I think one issue here is that ADEV is being used by one “lab" and
absolute frequency is being used by the other.
They ver
Hi
I think one issue here is that ADEV is being used by one “lab" and absolute
frequency is being used by the other.
They very much are *not* the same thing. There isn’t even a really simple way
to convert one to the other.
There will always be a big delta between those two measures. For absol
On Thu, September 1, 2016 11:54 am, Bert Kehren via time-nuts wrote:
> All the power work will not improve the frequency performance
> of the unit because the frequency is constantly changed
> to correct time.
Can't you control that to a large extent with the damping and time
constant parameter
We have been following the Tbolt power discussions but what I am missing is
the main problem with Tbolts. All the power work will not improve the
frequency performance of the unit because the frequency is constantly changed
to correct time. Tbolt is an excellent time device but not good for
James wrote:
Is there a problem running more than one Thunderbolt off of the same linear
supply (assuming the supply can support the current demands) or does each
Thunderbolt require its’ own separate linear supply?
I do not anticipate that multiple Tbolts would interact in a negative
manne
Jim,
I use a HP 6236B triple power supply to drive 2 each T'Bolts. Works fine
after the T'Bolts warm up, with limitations on a cold start up.
But once they warm up all is OK.
Using a common outside puck antenna and a HP RF distribution block I can
run 3 T'Bolts and get essentially the same r
Am 01.09.2016 um 16:36 schrieb jimlux:
On 8/31/16 10:24 PM, Gerhard Hoffmann wrote:
Am 01.09.2016 um 06:07 schrieb Bruce Griffiths:
I have a quad LT3042 PCB that I must get around to assembling.One
potential issue with the LT3042 is the relatively high noise at low
frequencies when the capaciti
Hi
The easy answer for a couple dozen Tbolts is a +15 V high current linear supply
and a low power -15 V linear. Wire them to regulators mounted on chunks of perf
board.
Bob
> On Sep 1, 2016, at 12:24 AM, DaveH wrote:
>
> Someone could come out with a circuit board for a single configurable
Hi
The gotcha is that an OCXO acts as a negative resistance load (current goes up
as voltage goes down).
That makes wiring up multiple units problematic. It is not impossible to do,
but you can get in trouble. Putting
regulation at each device eliminates the problem. It may be overkill, but the
On 8/31/16 10:24 PM, Gerhard Hoffmann wrote:
Am 01.09.2016 um 06:07 schrieb Bruce Griffiths:
I have a quad LT3042 PCB that I must get around to assembling.One
potential issue with the LT3042 is the relatively high noise at low
frequencies when the capacititve bypassing of the resistor that sets
Dave wrote:
The problem on eBay is "tested" means something quite different to what I know as
"tested'
Well, yes, but that's well-known. Ebay is what it is and ebay sellers
are what they are. No use grousing about it, just deal with it. The
important thing is to make sure you have a righ
Hi
For multiple TBolts, the simple answer is local regulation. LT1764’s work fine
for the +12 and +5 side. A well bypassed 79L12 can
do the trick for the -12. Feed them all of of a bulk +15 (high current)
llinear supply and a -15 with the lowest output you can find.
The gotcha is that if you
Is there a problem running more than one Thunderbolt off of the same linear
supply (assuming the supply can support the current demands) or does each
Thunderbolt require its’ own separate linear supply? Jim Robbins
___
time-nuts mailing list -- time-nu
Mike wrote:
I use the TAPR HPSDR LPU
I was unfamiliar with the LPU, so I took a look at the docs. It
develops several voltages, all from a +13.8v source. This means that
the -12v supply necessarily is a switching supply (to get the polarity
reversal). It is unfortunate that the power sup
On 2016-09-01 05:35, Charles Steinmetz wrote:
Bruce wrote:
Low noise regulators for the +12V and +5V outputs would also be useful.
Very true. By focusing on the -12v supply, I did not intend to
suggest that low noise is unimportant on the +12v and +5v supplies.
The suggestion to use LT304
Am 01.09.2016 um 07:44 schrieb Charles Steinmetz:
The datasheet shows both NPN and PNP current multipliers. Just
curious -- did you choose the NPN circuit for theoretical
considerations, and if so what was your reasoning -- the lower
open-loop output impedance?
More belly feeling. The PNP
Original message
From: Charles Steinmetz
Date:09/01/2016 06:07 (GMT+00:00)
To: time-nuts@febo.com
Subject: Re: [time-nuts] Anybody want a Thunderbolt power supply?
Randall wrote:
> Tested and guaranteed samples of all of these can be bought for $25-100
if you are patien
Bruce wrote:
It will show up if the value of the voltage setting bypass capacitor is
reduced. Both the Johnson and excess noise in this resistor coupled with the
current source flicker noise should become evident. The datasheet graphs
indicate that the Johnson noise of the voltage setting res
Post should have been:
Acts like noise current flowing in the voltage setting network (R || C).Flicker
noise appears to kick in below 1Hz or so.
Bruce
On Thursday, 1 September 2016 8:23 PM, Bruce Griffiths
wrote:
Acts like current noise flowing in the voltage sett
On Thursday,
I wrote:
I have converted a number of them by replacing the DC-DC converters
and feeding the circuitry from a mains-operated linear DC supply
This should read, "I have converted a number of them by *removing* the
DC-DC converters and feeding the circuitry from a mains-operated linear
DC
Gerhard wrote:
I have made a stamp-sized layout for LT3042 + external npn power transistor
as shown in the data sheet. Not fabricated, let alone tested.
Nice!
The datasheet shows both NPN and PNP current multipliers. Just curious
-- did you choose the NPN circuit for theoretical considerat
Randall wrote:
Wow, given all the responses about the cleanliness of the power into a Thunderbolt, I would be even
more interested in a power supply that did *not* leave the "last mile" up to me. I would
be more interested in a "pretty clean" power supply that I could just plug in and go.
A
34 matches
Mail list logo