Hi all,
After a couple years not doing anything except letting it sit in my
den and provide time for my home network, I've decided to start
hacking on my hobby project again.
For reference, what I've got right now is a Freetronics EtherMega
(ATMega2560-based Arduino clone with integrated W5100 et
Recently I have been comparing the phase noise of the HOlzworth HX4210 and the
LTC7957-4.
I have found that the performance of these devices is comparable with a 10MHz
sinewave input with a PN noise floor below -160dBc/Hz.
For offsets below 100Hz the LTC6957-4 is quieter and for offsets below 50Hz
You alternate LTC7957-4 and LTC6957-4 and it is only the later that exists.
The LTC6957-4 has a single-stage amplifier stage input, with somewhat
programmable bandwidth. I assume you used the 50 MHz BW setting.
Cheers,
Magnus
On 07/29/2014 10:55 AM, br...@ko4bb.com wrote:
Recently I have bee
Sorry, I meant the LTC6957-4 of course._SELA = l
FILTA = L
FILTB = H
ie an input stage BW of 160MHz as recommended for a 10MHz + 10dBm input.
Input for the HX4210 was +14dBm.
Comparator was that used in David Partridge's programmable divider (includes the
74AC04 buffers).
Bruce
> On July 29, 20
Bruce,
Thank you, that was very useful information. If I ever do a re-spin of the
divider I will likely use the LTC6957-3 or -4 instead of the ADCMP600 (I
would need interest for at least 40 boards to be able to do this at anything
like an economic price).
Will you be putting the full details
Further to my previous post:
I note that the LTC6957 is 3.3V CMOS rather than 5V. Do you have a
recommmendation for a level converter to 5V logic? Would a 74AC04 using a
5V supply cope well enough in that role or is there a better solution?
Regards,
David Partridge
-Original Message-
F
Am 29.07.2014 um 13:38 schrieb David C. Partridge:
Further to my previous post:
I note that the LTC6957 is 3.3V CMOS rather than 5V. Do you have a
recommmendation for a level converter to 5V logic? Would a 74AC04 using a
5V supply cope well enough in that role or is there a better solution?
However that will increase the signal transition times to significanly greater
than the 300ps seen at the LTC6957 output.
Bruce
> On July 29, 2014 at 7:54 AM Gerhard Hoffmann wrote:
>
>
> Am 29.07.2014 um 13:38 schrieb David C. Partridge:
> > Further to my previous post:
> >
> > I note that the
I merely used the evaluation board which has a capacitively coupled input.
The transformer coupled input circuit using a 1:4 (turns ratio) step up
transformer
as depicted on the datasheet should reduce the PN floor by at least 3dB for
10MHz input.
Bruce
> On July 29, 2014 at 7:30 AM "David C. Part
Am 29.07.2014 um 14:47 schrieb br...@ko4bb.com:
However that will increase the signal transition times to significanly
greater than the 300ps seen at the LTC6957 output.
I had standard sot23/sc70 Fairchild single cmos gates with rise/fall
times faster than 500ps.
Gerhard
___
One could possibly use another transistor pair in front of this one.
For lower rate signals, it is a great "finalizer" solution to a
step-wise increase in bandwidth and slew-rate.
Cheers,
Magnus
On 07/29/2014 02:54 PM, br...@ko4bb.com wrote:
I merely used the evaluation board which has a cap
Hej Bruce,
Many thanks for the clarification!
This could be an alternate input stage to the TADD-2 too.
Cheers,
Magnus
On 07/29/2014 12:59 PM, br...@ko4bb.com wrote:
Sorry, I meant the LTC6957-4 of course._SELA = l
FILTA = L
FILTB = H
ie an input stage BW of 160MHz as recommended for a 10MHz
Hi,
What comparator did you use in your evaluation? An 74AC04, 74AC14 or other
LT, AD, etc?
Regards,
Vasco Soares
- Original Message -
From:
To:
Sent: Tuesday, July 29, 2014 9:55 AM
Subject: [time-nuts] Sine to square wave converter Phase Noise
Recently I have been comparing t
Fellow time-nuts,
Things will shift in the sky. Lot's of changes.
SVN-33 is being decommissioned after 17.5 years of operation, with a 7
years designed lifetime, that's 2.5 times the operational lifetime, and
it's being decommissioned in a controlled fashion. Respect.
Cheers,
Magnus
--
Hi Magnus et al - just FYI: 2 1/2 times the design lifetime is not unusual
for satellites. More of the Ham Oscar satellites have exceeded their
lifetime by that much or more. (Sorry, no facts handy).
It saves us USA taxpayers money when they last that long!
Regards, John K1AE
Original Mes
Hi John:
And the manufacturer gets an annual bonus.
Have Fun,
Brooke Clarke
http://www.PRC68.com
http://www.end2partygovernment.com/2012Issues.html
http://www.prc68.com/I/DietNutrition.html
John Allen wrote:
Hi Magnus et al - just FYI: 2 1/2 times the design lifetime is not unusual
for satell
John,
It has delayed the launching of birds, as the old ones does not die of
quick enough for the planned schematic to maintain 24 birds, instead we
see 30-32 birds active for many years, and some being "off air" backups.
On the other hand, it gives more time to adjust the new birds with new
Lasting longer should be no surprise. The design spec in years is NOT
the mean time before failure. It is more like the 4-sigma time before
failure.
It is so far out there that many times what kills them finally is
running out of propellent. "Design lifetime" is kind of a
misleading term.
O
Hi
Put an L network in front of a biased NC7SZ04 running off of 5V and you should
get a floor that’s ~ -170 dbc/Hz at 10 MHz. $0.34 each at quantity =1 at
Mouser. The L network is set up to “what ever it takes” to give you 5V p-p on
the gate input. The load termination on the L acts as the 50 o
Hi,
A followup on Tom's thread on blixtortnung (lightning location) and the
possible use of lightning as a time transfer method.
It seems Darpa is reseaching positioning based on lightning.
https://medium.com/war-is-boring/gps-not-working-try-using-lightning-to-find-your-way-e75144bcf4dd
/Björ
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