Hi Andrea,
Making measurements of quartz oscillator aging is much easier than you think
and requires minimal equipment. In particular all you need is a GPS 1PPS and a
simple counter. No need to worry about sawtooth. Any $20 GPS/1PPS receiver will
work.
Consider this rough example of measuring
Bob -
I am maybe using the wrong word discernible. By that I mean that you cannot
discern phase noise from AM noise at the real low levels. You can certainly
measure, or see the contribution of the total noise power, but do not
necessarily know if it is phase noise or AM noise or how much of
Brooke,
The traditional GPS has C/A and P(Y) on L1 and P(Y) on L2.
Most Civilian GPSes only uses C/A.
Advanced receivers can also use P(Y) code, since the P-code is known,
the hand-off to P code is known and the way that P-code is encrypted
into Y-code is known (XOR with another code,
Björn,
On 01/15/2015 07:55 PM, Björn Gabrielsson wrote:
Brooke,
The traditional GPS has C/A and P(Y) on L1 and P(Y) on L2.
Most Civilian GPSes only uses C/A.
Advanced receivers can also use P(Y) code, since the P-code is known,
the hand-off to P code is known and the way that P-code is
Magnus,
If civilian receivers where to implement L2C and L5 which now is
becoming common, they would gain quite a bit of precision in a similar
fashion. For car navigation, the GPS would know which lane you are in.
There ARE civilian receivers doing this, and has been for quite some
years.
Magnus Danielson magnus@... writes:
Which display is it?
Hi Mangus,
I do not know the model name, but I found the same one on ebay (key word
2.2 TFT SPI). It's a SPI screen, so it shows things quite slow. However,
320x240 resolution is good to display a lot of slow changing stuffs. I use
As long as the instrument is carefully adjusted so the that the
measurement phase axis is correctly aligned with respect to the test
signal an interferometer can be used to ensure that the measurement
system PN noise floor is well below the thermal limit when measuring the
residual noise of 2
If we had dual or tripple frequency receivers below 500 USD things would
start to be interesting. If high-volume kits would be just twice as
expensive, it would be possible to consider for more luxury models.
Hi Magnus,
I am currently (but slowly) evaluating about a dozen near identical,
Hi -
I agree with what you stated, however, I am not sure that at real low levels
they are actually discernible. Regards - Mike
Mike B. Feher, EOZ Inc.
89 Arnold Blvd.
Howell, NJ, 07731
732-886-5960 office
908-902-3831 cell
-Original Message-
From: time-nuts
Tom Van Baak tvb@... writes:
Just use:
ref_delta = ref_curr - ref_prev;
sig_delta = sig_curr - sig_prev;
Not only is it much simpler but it also works in every case (your code
would fail whenever curr equals prev).
Here's a test program in case you don't believe me:
I have a page that illustrates how you can use a delay line and a mixer to
separately obtain AM and PM
http://www.ko4bb.com/Timing/Phase_Detector
Didier KO4BB
On January 14, 2015 1:19:11 PM CST, Mike Feher mfe...@eozinc.com wrote:
At those low levels, how does one differentiate between phase
On Mon, Jan 12, 2015 at 06:16:01PM -0500, Bob Camp wrote:
Actually it’s a bit worse than you might expect.
The uncorrected sawtooth will give you about 20 ns of wander. At the one day
level, GPS without some sort of ionosphere help (like a dual frequency
receiver) will add another 10 ns or
On Mon, Jan 12, 2015 at 03:10:39PM +0100, Attila Kinali wrote:
The GNSS Timing AppNote for the LEA6-T receiver[1] will give you an idea
what jitter you get with GPS. Please be aware that these measurements
were done with an antenna located at a _good_ position (ontop of a 4 story
building
Brooke,
The traditional GPS has C/A and P(Y) on L1 and P(Y) on L2.
Most Civilian GPSes only uses C/A.
Advanced receivers can also use P(Y) code, since the P-code is known,
the hand-off to P code is known and the way that P-code is encrypted
into Y-code is known (XOR with another code, called
I have been following this thread quietly. But will comment.
I noticed the construction methods. Lots of little holes.
That is all to familiar to me. Good to see others do the same around the
world.
The project is really coming along nicely.
Regards
Paul
WB8TSL
On Wed, Jan 14, 2015 at 4:58 PM,
Bob -
What I am saying is, even at the levels you mentioned, what is measured is I
believe the combination of phase and AM. In other words, you are just measuring
noise, but, are not certain if it is all phase, or phase plus some AM. At least
that is my recollection when I was heavily involved
Hi
I guess the question becomes how low is low.
If it’s a 50 ohm system
If the power level is rational
If you are at room temperature
There are some limits on how low low can be.
You have a -174 dbm / Hz thermal floor. AM or PM noise can only be 3db better
than the thermal floor. At a
Hi
On Jan 15, 2015, at 4:56 AM, Andrea Baldoni erm1ea...@ermione.com wrote:
On Mon, Jan 12, 2015 at 06:16:01PM -0500, Bob Camp wrote:
Actually it’s a bit worse than you might expect.
The uncorrected sawtooth will give you about 20 ns of wander. At the one day
level, GPS without some sort
Hi,
On 01/14/2015 10:58 PM, John Miles wrote:
Just now, I changed the way to calculate frequency and get a better
ADEV chart.
http://www.qsl.net/b/bi7lnq/freqcntv4/test/20150114/0114.gif
Looking good! Nice example of a white PM noise floor, just like a 'real' HP
counter. Let it run for a
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