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Path: ...!eternal-september.org!feeder3.eternal-september.org!news.eternal-september.org!.POSTED!not-for-mail From: Jeroen Belleman <jeroen@nospam.please> Newsgroups: sci.electronics.design Subject: Re: "Sampler??" Date: Tue, 30 Jul 2024 23:17:01 +0200 Organization: A noiseless patient Spider Lines: 161 Message-ID: <v8bl3e$16nn2$2@dont-email.me> References: <v85va8$19le$1@dont-email.me> <v86dsp$3n74$1@dont-email.me> <v878oa$gbtu$1@solani.org> <72gfajl8ke966lsu54bpajpang9dvgmt63@4ax.com> <v89sv9$hq1q$1@solani.org> <v8a9vr$v9r2$1@dont-email.me> <v8afo4$i3b7$1@solani.org> <v8aiaf$10lqo$1@dont-email.me> <v8auku$iedg$1@solani.org> <qsvhajlnfdb6tucj210seth6hmqalsfnt9@4ax.com> <v8avvb$13368$2@dont-email.me> <358iajpkaf41atvvnbq9no9p0uearvu8bk@4ax.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Injection-Date: Tue, 30 Jul 2024 23:14:23 +0200 (CEST) Injection-Info: dont-email.me; posting-host="d7741adb6dee930ecc5354eda5967bb6"; logging-data="1269474"; mail-complaints-to="abuse@eternal-september.org"; posting-account="U2FsdGVkX19mbzm6yODiB5Ijseu5G7OT" User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.13.0 Cancel-Lock: sha1:bfwHzzbbmy/1w7e13pZyW2NQSLU= Content-Language: en-US In-Reply-To: <358iajpkaf41atvvnbq9no9p0uearvu8bk@4ax.com> Bytes: 8584 On 7/30/24 19:46, Joe Gwinn wrote: > On Tue, 30 Jul 2024 15:13:47 -0000 (UTC), Cursitor Doom > <cd999666@notformail.com> wrote: > >> On Tue, 30 Jul 2024 11:01:17 -0400, Joe Gwinn wrote: >> >>> On Tue, 30 Jul 2024 14:51:10 GMT, Jan Panteltje <alien@comet.invalid> >>> wrote: >>> >>>> On a sunny day (Tue, 30 Jul 2024 11:20:47 -0000 (UTC)) it happened >>>> Cursitor Doom <cd999666@notformail.com> wrote in >>>> <v8aiaf$10lqo$1@dont-email.me>: >>>> >>>>> On Tue, 30 Jul 2024 10:36:51 GMT, Jan Panteltje wrote: >>>>> >>>>>> On a sunny day (Tue, 30 Jul 2024 08:58:35 -0000 (UTC)) it happened >>>>>> Cursitor Doom <cd999666@notformail.com> wrote in >>>>>> <v8a9vr$v9r2$1@dont-email.me>: >>>>>> >>>>>>> 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. :( >>>>>> >>>>>> Would be nice to see a real circuit diagram of that thing. >>>>>> What is the model / type number? >>>>>> I am curious. >>>>>> So far I have been able to find circuits for most stuff I came across >>>>>> with google. >>>>> >>>>> It's the HP8566B - a very well known lab-grade analyser of the day >>>>> which many RF designers still use. There is a *ton* of service info on >>>>> this model online. However, I have not been able to see a *proper* >>>>> schematic for the "sampler" in the A11A5 board which is where the issue >>>>> is. >>>> >>>> OK, thank you, I will google a bit.. >>>> I got the user manual now: >>>> https://elektrotanya.com/ >> hp-8566b_spectrum_analyzer_100hz-2.5ghz_2-22ghz_usr- >> programming_1984_sm.pdf/download.html#dl >>>> Then trouble shooting manual part 1 >>>> https://xdevs.com/doc/HP_Agilent_Keysight/ >> HP%208566B%20Troubleshooting%20&%20Repair%20Vol.%201.pdf >>>> Seems to have at least some circuits (just a quick look) >>>> and part 2 >>>> https://xdevs.com/doc/HP_Agilent_Keysight/HP%208566B, >> %208568B%20Troubleshooting%20&%20Repair%20Vol.%202.pdf >>>> also has some circuits I will have a look at the hundreds of pages, will >>>> take some time. >>>> I presume you have these? >>>> Took 10 seconds to find with google >>>> >>>> OTOH my 1.4 GHz RTL_SDR sticks cost 30 dollies($$) or so, >>>> https://www.ebay.com/p/22032165355?iid=335019807057 >>>> I can use a 5 dollies($$) satellite LNB as down mixer to go from 10 to >>>> 12 GHz to say 1 GHz (modified a LNB for xtal locked to Rubidium >>>> reference) >>>> Also build a small downmixer so it can see 2.4 GHz too Plenty free >>>> spectral display programs online for it, >>>> I wrote my own: >>>> https://panteltje.nl/panteltje/xpsa/index.html >>>> it also has an 'harmonic' button to look for the next harmonic when you >>>> select a carrier... >>>> The latest version has some more stuff and runs on Raspberry Pi.. >>>> The RTL_SDR sticks can even receive GPS signals... >>>> https://panteltje.nl/pub/run_50_outside_2728000.gif uses this guys >>>> software<; >>>> http://michelebavaro.blogspot.nl/2012/04/spring-news-in-gnss-and-sdr- >> domain.html >>>> >>>> For 100 Hz to 20 kHz a PC soundcard or maybe USB audio stick (as I use >>>> for my Raspberry) >>>> and there are several audio programs with spectrum display >>>> >>>> There are so many possibilities... >>> >>> HP always put the theory notes in the HP Journal, so I'd suggest >>> searching there for the HP8566B, in the issues around when the >>> instrument was first introduced. >> >> This analyser is well over 30 years old, so whatever's gone wrong is most >> likely age-related and wouldn't have come to light for many years. >> Fortunately there's a lot of info out there - *if* you can find it! > > On the lack of a schematic, I did dig into how it worked many years > ago, and as I recall it was based of some fancy abuse of a slotted > rectangular waveguide which supported various orthogonal modes - this > cannot be described by any lumped-parameter circuit. > > Try this: > > US4647795A, Travelling wave sampler, Agoston Agoston, Beaverton, Oreg. > Tektronix, Inc., Beaverton, Oreg. granted 3 March 1987. > > .<https://patents.google.com/patent/US4647795A> > > It does have schematics, in a manner of speaking. > > Joe Gwinn If it's Agoston's, it's a genuine time-domain short-pulse sampler, not an attenuator pick-off. Jeroen Belleman