Since the spur moved in frequency when the amplitude of the 25 MHz
interference changed, my guess is that you have some grounding or cable
leakage issues which are causing the measuring system to produce
erroneous results due to overloading. Do you have all instruments and
sources plugged into the
Hi
I would bet that the spur moving is an indicator of either the 25 MHz
transmitter carrier or
modulator drifting in frequency. My guess is that the Maser does not drift :)
Bob
> On Jan 20, 2017, at 12:22 PM, Anders Wallin
> wrote:
>
> I made some progress with this issue today.
> It turns
I made some progress with this issue today.
It turns I was using a 75Ohm cable at some point (doh!) which caused a
'forest' of spurs far out. Possibly our other maser has a faulty/cut cable
which behaves similarly.
The final fix was to turn off our 25 MHz radio time-code transmitter which
was causi
Thanks for all the comments so far.
I will try the doubler with another quieter source, and try removing
various potential noise-sources and exchanging cables...
I have now uploaded a few more images of the same data to the shared album
linked in my earlier post.
Anders
On Thu, Jan 19, 2017 at 1
I see spurs at 50 Hz and harmonics, which I assume are from the power
line at your location. This might be due to an oscillation in the power
supply regulator, leading to nonlinear regulator operation and
feedthrough of power line ripple. For example, low dropout regulators
can sometimes oscillate
You may find that the behavior varies quite a bit depending on what you put
between the maser output and the doubler. I've seen one case in particular
that generates a ton of PM spurs, specifically an HP 11721A doubler driven by
the 5 MHz output of a 5061A Cs standard. The 5 MHz output uses a
Hi,
Considering that you have a diode and a tuned LC-tank, the tank will
"ring" in it's own frequency, even if it is driven by the diode and 5
MHz. This creates a single side-band tone which then shows up both as AM
and PM. Well, that is my guess. 1.5 Hz is however very very close, which
is q
Hi
Without seeing the circuit involved it’s a bit tough to guess all of the
possible
things that might be happening. One branch leads off to things like the circuit
it’s self oscillating and creating the spur. Sub branches involve oscillation
in
a regulator at low frequency vs RF oscillation so
Hello,
can you share also the Phase Difference trace?
cheers,
Mattia
2017-01-18 17:13 GMT+01:00 Anders Wallin :
> I'm seeing +20-30 dBc/Hz of excess AM/PN, as well as a strong 1.5 Hz spur
> created by frequency doubling from 5 MHz to 10 MHz.
> https://goo.gl/photos/GFx9tQoxrSmyzUQo8
> The input
I'm seeing +20-30 dBc/Hz of excess AM/PN, as well as a strong 1.5 Hz spur
created by frequency doubling from 5 MHz to 10 MHz.
https://goo.gl/photos/GFx9tQoxrSmyzUQo8
The input amplitude to the doubler should be just above the recommended 11
dBm.
What's going on??
thanks!
Anders
___
10 matches
Mail list logo