That sounds like phase-locking the oscillators to a local radio transmitter.
Not sure there is any difference post-processing vs. real time. - Lifespeed
Hi
A far more common approach is to let the two oscillators free run and to record
something like a local broadcast station. You then
I was afraid of that, I guess it doesn't hurt to ask. Perhaps I could
implement an ISM band radio link for the purpose of locking the two
oscillators. Of course that wouldn't reach a couple miles either. - Lifespeed
Hi
A *lot* depends on your definition of “phase locked”. If indeed
I may already know the answer to this, but I figured I would ask the time nuts
anyway. I have an application where I would like to phase-lock two oscillators
together, probably 10MHz OCXOs as they have particularly good Allen Deviation
compared to what I would ultimately like to use, a 100MHz
Hi,
Been a while since I visited, I recall there are many, well, time nuts here. I
am trying to track down a source of phase noise in a frequency synthesizer
design. One part of the frequency reference upconverts a DDS and then divides
it down again using a digital divider - standard
Hi Guys. It has been a while since I posted, hope you can help with a slightly
time-related topic. Can't have frequency without amplitude . . .
I recently designed an Automatic Level Control circuit consisting of dual-slope
detector logger, open and closed loop references with AM modulation,
Date: Tue, 20 Apr 2010 18:59:20 -0700
From: jimlux jim...@earthlink.net
Subject: Re: [time-nuts] GPS 1 PPS accuracy limits
Do they have other requirements (Allan deviation? phase noise?)
Over what time span do they want 4E-11 accuracy? 1 second, 1000 seconds,
days?
A synthesizer locked to a
Why would flicker noise be a concern if there is no dc current flowing
in the switches?
Bruce
Hi Bruce,
Does it matter if the current is DC or AC? I expect to see +/-20 mA current
due to the signal level.
Clay
From: Bob Camp li...@rtty.us
Subject: Re: [time-nuts] 10 MHz reference
From: Bob Camp li...@rtty.us
Subject: Re: [time-nuts] Realistic Tbolt phase noise
Hi
I think you will find that the noise floor of the ADF4107 (dividers and
phase detector) is a bit higher than -150 at 100 Hz offset at 10 MHz. It
should get you past the -120 level though. That's still much
Hello Time Nuts,
I'm back again. I designed bandwidth-limited (30 MHz) ADA4899-1 opamp circuits
to buffer the 10 MHz reference, with theoretical noise of less than 3 nV/rtHz.
Oscillator noise is about -155 dBc/rtHz from 1 KHz to 10 KHz, and -160 dBc/rtHz
from 10 KHz to 100 KHz.
From: Henry Hallam he...@pericynthion.org
Subject: Re: [time-nuts] Are the days of buying a crystal numbered?
Anybody know what its performance is like under vibration?
Henry
Just guessing here . . . poor
Unless it is a specifically G-hardened device, it is sure to be microphonic.
All
Date: Fri, 19 Feb 2010 17:38:50 -0700
Subject: [time-nuts] OT: HP 8590A
Since the list members are familiar with lots of test equipment, I'd
like to ask what the folks here think about the HP 8590A Spectrum
Analyzer. Is this model ok? Are there any particular failures I should
be aware of in this
From: Bruce Griffiths bruce.griffi...@xtra.co.nz
Subject: Re: [time-nuts] Advice on 10 MHz isolation/distribution
Its easy to calculate a lower bound to the amplifier phase noise floor
from the signal level at the output and the amplifier output noise due
to feedback resistors together with the
From: Pete Rawson peteraw...@earthlink.net
Subject: Re: [time-nuts] Advice on 10 MHz isolation/distribution
To: Discussion of precise time and frequency measurement
time-nuts@febo.com
Message-ID: 1027d446-fe23-45a7-88ad-1cfd339c4...@earthlink.net
Content-Type: text/plain; charset=us-ascii
From: Bruce Griffiths bruce.griffi...@xtra.co.nz
Subject: Re: [time-nuts] Advice on 10 MHz isolation/distribution
(Clay)
The calculation is useful to help eliminate amplifiers that will not
meet the phase noise floor specs.
The amplifiers that remain will then need to be tested/measured for
Message: 6
Date: Fri, 19 Feb 2010 15:17:44 -
From: Garry Thorp gth...@pascall.co.uk
Subject: Re: [time-nuts] Advice on 10 MHz isolation/distribution
Hello Clay,
Joining in this discussion at a rather late stage - have you
considered using 74AC series gates as buffers? They provide
Any opinions on the suitability of the TI OPA820 as a 10 MHz distribution amp?
The voltage noise is only 7 nV/rtHz @ 100 Hz (gain=2, I'll be using g=1), which
is the best I've seen so far for a wideband amp. Not as good as the discrete
transistor circuit, but it would use alot fewer parts.
If I can believe the simulation (a big if) the ADA4899-1 can provide 90 dB
isolation at 10 MHz, rolling up to 70 dB at 100 MHz, when configured with a
gain of +2
The subcircuit model provided by ADI is useless for noise, unfortunately. I
guess I'll have to build and measure, which I don't
From: Martyn Smith mar...@ptsyst.com
Subject: [time-nuts] Phase Noise of 74AC gates
I'm not about to say how we achieve -170 dBc/Hz phase noise, but we
definitely don't use op amps or logic gates!!
Regards
Martyn
Is this an advertisement? I don't think anybody believes a logic gate provides
Date: Thu, 18 Feb 2010 15:22:40 +1300
From: Bruce Griffiths bruce.griffi...@xtra.co.nz
Clay
What's the effect of assigning the same label (Vout_2) to the outputs of
both output amplifiers as shown in your circuit schematic?
Bruce
Hi Bruce,
Duplication of the Vout_2 net labels (copy and paste
Message: 5
Date: Thu, 18 Feb 2010 11:11:18 -0800
From: Hal Murray hmur...@megapathdsl.net
Subject: Re: [time-nuts] Advice on 10 MHz isolation/distribution
(Clay)
Thank you, but I require a circuit without transformers
for reasons of vibration susceptibility.
Is the problem wires moving
Message: 5
Date: Thu, 18 Feb 2010 17:13:55 -0500
From: Bob Camp li...@cq.nu
Subject: Re: [time-nuts] Advice on 10 MHz isolation/distribution
(Clay)
To: 'Discussion of precise time and frequency measurement'
time-nuts@febo.com
Message-ID: 13d264786a8a41e781bb4e53c1dd9...@vectron.com
The TI THS3201-EP was looking pretty good for a high speed opamp. But the
input current noise graph doesn't go below 100 KHz and is climbing pretty
steeply at that point.
Clay
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Message: 3
Date: Thu, 11 Feb 2010 23:02:30 -0500
From: Bob Camp li...@cq.nu
Subject: Re: [time-nuts] Advice on 10 MHz isolation/distribution
(Clay)
Hi
I suspect your noise spike can be cured by a series R-C to ground from the
junction of Q1 base, Q7 base and all the other stuff. Something
I seem to not be accomplishing much isolation from output to input, as well as
output to output. Have I fumbled PSPICE somehow? For each simulation, Vac was
set separately, with V1=0.707V at the input, while V6=0V at the output (sim1).
Then V1=0V, and V6=0.01V (sim2).
Message: 2
Date: Thu, 11 Feb 2010 07:54:40 -0500
From: Bob Camp li...@cq.nu
Hi
Implementing that circuit without using a hybrid would be a bit of a challenge.
Bob
Message: 6
Date: Fri, 12 Feb 2010 04:09:08 +1300
From: Bruce Griffiths bruce.griffi...@xtra.co.nz
Yes implementing an exact copy
Message: 1
Date: Thu, 11 Feb 2010 12:42:27 -0500
From: Bob Camp li...@cq.nu
Subject: Re: [time-nuts] Advice on 10 MHz isolation/distribution
amplifier(Clay)
Hi
I really should learn how to read the whole message
Cancel the second request on vibe info.
-
The gotcha with
Message: 2
Date: Fri, 12 Feb 2010 12:12:29 +1300
From: Bruce Griffiths bruce.griffi...@xtra.co.nz
The output (collectors of Q5, Q6 emitter of Q4) of the input amplifier
sets the dc voltage at the inputs ( Q1 base, Q7 base respectively) of
the output amplifiers.
The circuit consists of a unity
Avoiding transformers and inductors will make it virtually impossible to
achieve very low phase noise as the dc gain from say the base of any
transistor in the chain to the output will degrade the flicker phase
noise. Using transformers or using an inductor to shunt any collector
resistors
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