On 7/1/20 4:59 PM, Bob kb8tq wrote:
Hi
Um …. e …..
If the phase spur is at 1.5 Hz at 10 MHz, it still will be at 1.5 Hz at 1296.
The multiplication process
does not change the offset frequency.
What you *do* get is a change in level. If the spur is 40 db down at 10 MHz,
then it goes
FB
I was thinking of FM on the (30 MHz) carrier. (which the FM- the
deviation will multiply) .
(A multiplication does not change the information rate of course)
BUT you are right ! that's not what will happen, there is no FM !
there are (relatd) unmodulated discrete frequency
RRR
Stability over about a 2 minute period, preferably within a Hz at 1296
MHz , IE about 1e-09 is all that is required. I'll make it and figure
out what I missed :-). The unwanted sideband (and some of the original
will of course leak through depending on the DBM balance) will generate
Hi
The same “small fraction of a degree” and “small fraction of a db” issues that
plagued the analog SSB
generation process still get into this approach. For “good” ADEV you need spurs
down below the
-130 dbc range (and likely much lower). This only gets you to 60 db or so ….
Bob
> On Jul 1,
Hi
Um …. e …..
If the phase spur is at 1.5 Hz at 10 MHz, it still will be at 1.5 Hz at 1296.
The multiplication process
does not change the offset frequency.
What you *do* get is a change in level. If the spur is 40 db down at 10 MHz,
then it goes up by 10 log (1296 / 10).
Net
Hi Bob
I imagine in physics there are times when you want an oscillator to move
a few Hz for offset, and the oscillator is fixed due to some physical /
atomic property.
yes, the whole thing will be phase locked, so no issue with freq error.
For a fixed frequency operation , +45 and -45 deg
Hello Glen,
Any progress on the Anylocker? I’d still like to get two for the FT817, 1pps
input first choice, 10 MHz second choice.
Cheers,
Steve
WB0DBS
> On Jul 1, 2020, at 2:30 AM, glen english LIST
> wrote:
>
> Hello group
>
> I have an idea that might work, and I wanted to discuss
Hi
There is a NIST paper (somewhere) that has an example of doing this. Like any
image
reject mixer approach, it only does just so well. It’s no different than
generating SSB
the same way. You get a spur that is 40 to 60 db down at the “image” frequency.
You can
tweak this or that to get it
Hello group
I have an idea that might work, and I wanted to discuss with likeminded
that might already have experience with the problem.
Shifting a fixed oscillator a few Hz using a image reject mixer.
background : From time to time I (and others) make lock boards for ham
gear, pulling the
