Re: "Sampler??"

On Tue, 30 Jul 2024 17:34:51 -0700, john larkin wrote:

On Tue, 30 Jul 2024 21:58:44 -0000 (UTC), Cursitor Doom
<cd999666@notformail.com> wrote:
 

On Tue, 30 Jul 2024 21:08:34 -0000 (UTC), Cursitor Doom wrote:
>

On Tue, 30 Jul 2024 13:15:59 -0700, john larkin wrote:
 

On Tue, 30 Jul 2024 19:21:28 -0000 (UTC), Cursitor Doom
<cd999666@notformail.com> wrote:
 

On Tue, 30 Jul 2024 10:39:37 -0700, john larkin wrote:
>

On Tue, 30 Jul 2024 08:58:35 -0000 (UTC), Cursitor Doom
<cd999666@notformail.com> wrote:
 

On Tue, 30 Jul 2024 05:16:24 GMT, Jan Panteltje wrote:
>

On a sunny day (Mon, 29 Jul 2024 09:29:04 -0700) it happened john
larkin <jlarkin_highland_tech> wrote in
<72gfajl8ke966lsu54bpajpang9dvgmt63@4ax.com>:
 

On Mon, 29 Jul 2024 05:19:06 GMT, Jan Panteltje
<alien@comet.invalid> wrote:
>

On a sunny day (Sun, 28 Jul 2024 21:40:41 -0000 (UTC)) it
happened Cursitor Doom <cd999666@notformail.com> wrote in
<v86dsp$3n74$1@dont-email.me>:
>
>

I still can't see where the 'sampling' bit comes into it.
AFAICT,
there's are two signals into this thing and one signal out. The
signal from the LHS is passed through a very fast diode which
generates harmonics from that fundamental. The signal from the
RHS is unmodified and mixed with the desired harmonic to give
the necessary output signal which is then filtered to get rid
of the unwanted mixing products. If that's all correct, as I
believe it is,
where does any *sampling* come into it?

>
A 'sampler' is fact a non-linear mixer.

>
In the audio world, a "mixer" is a linear summer.
>
In RF, a mixer is usually a multiplier, typically a 4-quadrant
diode thing or a Gilbert cell type circuit. Or a 2-quadrant thing
like a pentode. Or even a single diode. All do some flavor of
multiplying.
>
Some mixers inherently multiply a signal by a square wave, which
resembles other multiplier-type things once you lowpass filter
the output. That's a "synchronous detector", which we usually do
in an FPGA.
>
A sampler is a signal multiplier too.
>
These are all variations on the basic idea of multiplying two
signals.

 
A the word 'mixer' in RF is not the same as a multiplier,,
Multipliers are like harmonic generating stages say you have a 1
MHz distorted sine wave and then a second stage tuned at 3 MHz,..
turned to third harmonic.
 
mamamatical speaking RF mixing is indeed multiplication.
 
Like Shakepierce once said:
 "What's in a name..." CocaCola wihout coke

>
I think in this context, HP is using the term "sampler" to mean
something which 'sniffs' a small amount of a signal for testing
purposes. Like a few turns of wire around a transmission line will
'sniff' a small sample of what's going on in the line.
Where I went wrong was rigidly thinking HP meant 'sampling' in the
manner a sampling oscilloscope works. That's what threw me. I tend
to interpret things very literally. :(

 
The sampler in the SA schematic is precisely the sort of sampler
used in a sampling scope. It contains a step-recovery diode impulse
generator and no doubt some sampling diodes.

>
How can you say that when you haven't seen the schematic? If you've
been able to find it online somewhere then kindly post a link to it
here.

 
You posted an excerpt from the HP manual where the sampler is
described.

 
But you said:
"The sampler in the SA schematic is precisely the sort of sampler used
in a sampling scope."
 
So you must have had sight of the schematic. I'd really appreciate it
if you could post a link to it.

 
No, all I saw was the description.
 
 

Also, you said the SRD was acting as an "impulse generator" when I
assumed it was simply generating harmonics to boost the M/N loop output
up in order to mix with the output of the YTO.

 
They are really the same thing. An impulse train is a harmonic comb.

So we're just getting hung up on definitions? Fine, let's leave it at
that.