-Original Message-
On Behalf Of Magnus Danielson
Didier skrev:
John,
When you add two (statistically independent) 5 MHz signals
and get a 10MHz signal, the 10 MHz signal's *relative* noise
and drift will be the average of the *relative* noise and
drift of the two 5 MHz
On 12/24/08 6:04 AM, Didier did...@cox.net wrote:
-Original Message-
On Behalf Of Magnus Danielson
Specifically, John was suggesting adding the two 5MHz signals, instead of
locking them, that's why I added statistically independent.
So as when you average n signals, the noise
Didier wrote:
Square root of 2 is about 1,414 or about 3,01 dB.
I am always confused when considering noise, is it 10*log(p1/p0) or
20*log(p1/p0)?
A moment's reflection on why the 10 log vs. 20 log, might help.
The conversion from a power ratio to dB is:
dB = 10 log (P1/P2)
Remember
Didier skrev:
-Original Message-
On Behalf Of Magnus Danielson
Didier skrev:
John,
When you add two (statistically independent) 5 MHz signals
and get a 10MHz signal, the 10 MHz signal's *relative* noise
and drift will be the average of the *relative* noise and
drift of the two
At 5:05 PM + 12/23/08, time-nuts-requ...@febo.com wrote:
Date: Tue, 23 Dec 2008 11:40:51 -0500
From: John Ackermann N8UR j...@febo.com
Subject: [time-nuts] New topics (was Re: He is a Time-Nut
Troublemaker)
To: Discussion of precise time and frequency measurement
time-nuts
- Original Message -
From: Joe Gwinn joegw...@comcast.net
To: time-nuts@febo.com
Sent: Wednesday, December 24, 2008 3:52 PM
Subject: Re: [time-nuts] New topics (was Re: He is a Time-Nut
Troublemaker)
At 5:05 PM + 12/23/08, time-nuts-requ...@febo.com wrote:
Date: Tue, 23 Dec 2008 11:40:51
...@comcast.net
To: time-nuts@febo.com
Sent: Wednesday, December 24, 2008 3:52 PM
Subject: Re: [time-nuts] New topics (was Re: He is a Time-Nut
Troublemaker)
At 5:05 PM + 12/23/08, time-nuts-requ...@febo.com wrote:
Date: Tue, 23 Dec 2008 11:40:51 -0500
From: John
Magnus Danielson wrote:
My intent is to get some stuff done in the lab during the vacation.
(Desperatly trying to get some more on-topic discussions going).
Here are two questions that have been running around my head:
1. Following on from the discussion last week about trying to
-Original Message-
From: time-nuts-boun...@febo.com
[mailto:time-nuts-boun...@febo.com] On Behalf Of John Ackermann N8UR
Sent: Tuesday, December 23, 2008 8:41 AM
To: Discussion of precise time and frequency measurement
Subject: [time-nuts] New topics (was Re: He is a Time-Nut
John Ackermann N8UR skrev:
Magnus Danielson wrote:
My intent is to get some stuff done in the lab during the vacation.
(Desperatly trying to get some more on-topic discussions going).
Here are two questions that have been running around my head:
1. Following on from the discussion
-Original Message-
From: time-nuts-boun...@febo.com
[mailto:time-nuts-boun...@febo.com] On Behalf Of Magnus Danielson
Sent: Tuesday, December 23, 2008 9:26 AM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] New topics (was Re: He is a Time-Nut
Magnus Danielson wrote:
This diffrential locking technique could be applied to atomic standards,
but then naturally require much improved solution than simple
oscillators. The diffrential locking technique does not magically solve
issues that is typically common mode, such as temperature
John Ackermann N8UR skrev:
Magnus Danielson wrote:
This diffrential locking technique could be applied to atomic standards,
but then naturally require much improved solution than simple
oscillators. The diffrential locking technique does not magically solve
issues that is typically
2. Several measurement techniques require a given phase relationship
(e.g., quadrature) between DUT and reference. For HF frequencies (ie,
5 or 10 MHz) is there a *practical* phase shifter design covering
180+ degrees that doesn't involve switching various lengths of coax
in and out of
and frequency measurement
Subject: Re: [time-nuts] New topics (was Re: He is a Time-Nut
Troublemaker)
2. Several measurement techniques require a given phase
relationship
(e.g., quadrature) between DUT and reference. For HF
frequencies (ie,
5 or 10 MHz) is there a *practical* phase
Hal Murray said the following on 12/23/2008 01:58 PM:
2. Several measurement techniques require a given phase relationship
(e.g., quadrature) between DUT and reference. For HF frequencies (ie,
5 or 10 MHz) is there a *practical* phase shifter design covering
180+ degrees that doesn't
John Ackermann N8UR skrev:
Hal Murray said the following on 12/23/2008 01:58 PM:
2. Several measurement techniques require a given phase relationship
(e.g., quadrature) between DUT and reference. For HF frequencies (ie,
5 or 10 MHz) is there a *practical* phase shifter design covering
180+
John Ackermann N8UR wrote:
Hal Murray said the following on 12/23/2008 01:58 PM:
2. Several measurement techniques require a given phase relationship
(e.g., quadrature) between DUT and reference. For HF frequencies (ie,
5 or 10 MHz) is there a *practical* phase shifter design covering
[mailto:time-nuts-boun...@febo.com] On Behalf Of John Ackermann N8UR
Sent: Tuesday, December 23, 2008 12:29 PM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] New topics (was Re: He is a Time-Nut
Troublemaker)
Hal Murray said the following on 12/23
PLL up by a factor of N, use that to drive a DDS, then filter. Maybe
a pair of DDSes will get better tracking.
For each possible phase offset, you need N slots in the table. (N/4
with more work)
If doing phase noise or short term stability measurements, wouldn't
the noise of the DDS
John Ackermann N8UR wrote:
Hal Murray said the following on 12/23/2008 01:58 PM:
2. Several measurement techniques require a given phase relationship
(e.g., quadrature) between DUT and reference. For HF frequencies (ie,
5 or 10 MHz) is there a *practical* phase shifter design covering
Bruce Griffiths skrev:
John Ackermann N8UR wrote:
Hal Murray said the following on 12/23/2008 01:58 PM:
2. Several measurement techniques require a given phase relationship
(e.g., quadrature) between DUT and reference. For HF frequencies (ie,
5 or 10 MHz) is there a *practical* phase
Magnus Danielson wrote:
Bruce Griffiths skrev:
John Ackermann N8UR wrote:
Hal Murray said the following on 12/23/2008 01:58 PM:
2. Several measurement techniques require a given phase relationship
(e.g., quadrature) between DUT and reference. For HF frequencies (ie,
5
Hej Bruce,
See patent US3803499 for one implementation of this scheme.**
Using a quadrature hybrid to combine the two signals and achive the 90
degrees offset is one of several approaches. It is however just a matter
of trigonometry at work.
**However, where possible, a lower noise more
Magnus Danielson wrote:
Hej Bruce,
See patent US3803499 for one implementation of this scheme.**
Using a quadrature hybrid to combine the two signals and achive the 90
degrees offset is one of several approaches. It is however just a matter
of trigonometry at work.
Hej Bruce,
Rephrasing:
A lower noise system with less phase instability due to the variable RF
gain mixer is possible when the phase shift contribution from the
circuit branch including said mixer is small.
Should I interprent this as when the phase shifts near 0, 90, 180 and
270 degrees
Magnus Danielson wrote:
Hej Bruce,
Rephrasing:
A lower noise system with less phase instability due to the variable RF
gain mixer is possible when the phase shift contribution from the
circuit branch including said mixer is small.
Should I interprent this as when the phase shifts
Hej Bruce,
Hej Magnus
Thats true, but I had the more general case in mind wherein which one
adds coarse fixed delay increments as required and merely uses the
variable gain mixer to make a fine adjustment to the phase.
How do you intend that to work? Slightly introduce the signal with a
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