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From: Cursitor Doom <cd999666@notformail.com>
Newsgroups: sci.electronics.design
Subject: Re: "Sampler??"
Date: Wed, 31 Jul 2024 07:24:04 -0000 (UTC)
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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.