To Erik:
Hi. The PNA block diagram I posted earlier had two errors. I
corrected them in PNA V2.0, as shown in PMA2.PNG
The first error was a missing connection to the Phase-Frequency
Detector (PFD). This was a trivial error and was due to issues with
the image viewer dropping lines. Do not mess
Hi
> On Jul 8, 2022, at 10:35 AM, Mike Monett via time-nuts
> wrote:
>
> Bob, you wrote:
>
>> Mike. One concern I have with active components as mixer is noise.
>> For an SA I designed only a passive DB diode mixer had low enough
>> output noise. Would a PF detector as being an active
Bob, you wrote:
> Mike. One concern I have with active components as mixer is noise.
> For an SA I designed only a passive DB diode mixer had low enough
> output noise. Would a PF detector as being an active component,
> not create more noise as output? Erik
> Yes, you are correct. The only
You wrote:
> On Tue, July 5, 2022 5:27 am, Mike Monett via time-nuts wrote:
>> The phase-frequency detector has zero ripple at lock.
> The PF detector also locks at 0 degrees offset. How do you get the
> demodulated phase noise out of that?
[...]
> Chris Caudle
The phase noise is contained
Hi
Indeed you can switch the gain of the amp. You still need to provide
a low gain output to feed the EFC input on your reference. The chain
to feed the sound card will be crazy high gain for the typical TCXO or
OCXO. Don’t even think of running that sort of gain into a VCO ….
Bob
> On Jul 8,
Bob,
Clear, you have a lot more experience and knowledge. For me this is
typical a case of "If you don't know about something it must be simple"
So best would be to make it possible in the simple PNA to switch off the
opamp gain, without changing the impedance the mixer sees, so the
offset
Hi
Like it or not, the mixer is a non-linear load. It also has a frequency
dependence. Even with “saturation” levels, the slope can and does
change. That’s the short list, as you dive into it, things get even more
complex in terms of “might be” sort of issues.
How can you be in saturation and
Bob
This confuses me.
The calibration of the system changes ( or can change ) each and every time you
swap
out signal sources. The levels are not going to be consistent setup to setup.
Thus you
calibrate each and every time you change out either device.
Assuming each source is saturating the
Hi
(see below)
> On Jul 7, 2022, at 10:10 PM, Erik Kaashoek wrote:
>
> Bob,
> You may have explained this before but I still do not understand.
> Does the phase modulation slope at the detector depend on the depth of the
> phase modulation? I think not.
The “phase modulation” you are looking
Not something I want to implement on short notice but maybe for the future.
The biggest limitation in this DIY PNA is the phase noise of the
reference OCXO and the noise of the opamp amplifying the output of the
mixer.
So I was wondering if it would make sense to do the following
1: Split the
You wrote:
> Mike,
> He was using an analog mixer, but your comment about XOR mixer does
> not apply to analog mixers. Your oversimplification that analog
> mixer and XOR gates being the same thing does not apply here, and
> thus the assigned missbehavior does not carry over to the
Hi,
Well, both amplitudes can be measured. The method I refer to is one of
several out of NIST, so it's not one of my own invention. See their AM
and PM Calibration material.
Using multiple methods you can evaluate how well the method functions.
The side-tone method generates known PM with
Bob,
You may have explained this before but I still do not understand.
Does the phase modulation slope at the detector depend on the depth of
the phase modulation? I think not.
With 57 degrees one should get an output voltage that is to be regarded
as the 0dBc level but this can not be measured
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