Rectify 500MHz Small Signal
in [Design]
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From: osr on 30 Sep 2009 21:50 I've had fun with two hobbyist concepts: The Lambda Diode: http://users.tpg.com.au/users/ldbutler/NegResDipMeter.htm http://www.zen22142.zen.co.uk/Theory/neg_resistance/Oscillations%20and%20Regenerative%20Amplification%20using%20Negative%20Resistance%20Devices.pdf The psuedo PUT: http://www.4qdtec.com/putpr.html In defense of the guy who runs 4QD, his golf cart controllers are really good. And for those of you who bemoan the fact that you cannot get your hands on fast sampling bridges , these show up on ebay and use a all analog PLL with a sampling bridge picking off the 900-1600 mhz drive oscillator , before it goes into the SRD multiplier. The bridge is driven by a 90-120 mhz crystal oscillator. They come in 2.5 ghz, 5-6 ghz and 8-11 ghz flavors. The SRD is in a tiny pill package in a ridge waveguide. 20-40$ usually. There is almost always a brick or two on ebay. Tech data is here: Frequency Sources (West Division) model MS-62XEL-52. Just about all of them use the same circuit, but some have better sampling systems. The sampler almost always ties into a probe extended into the "sapphire rod" cavity oscillator. Some performance data are here: http://www.thegleam.com/ke5fx/brick/brick.htm http://www.mpulsemw.com/Sampling_Phase_Detectors.htm http://www.skyworksinc.com/uploads/documents/200328B.pdf So if you do some digging at a good hamfest, you can come away with 2-3 bricks and some nice fast diodes :-) I do 10 Ghz ham stuff, its more of a challenge then a store bought 2 meter rig. These days your expected to forgo the old Gunn diodes and have tunable SSB locked to GPS or or a used Rb oscillator from a old cell site. Steve
From: ehsjr on 30 Sep 2009 21:52 Snipped from the following: Joerg wrote: > John Larkin wrote: >> >> Isn't this beautiful? >> >> ftp://jjlarkin.lmi.net/Z250A.jpg >> ftp://jjlarkin.lmi.net/Z250_TDR.jpg >> >> (TDR of the test trace, J28 to J29) >> > > That is indeed beautiful. Although, to be honest, I never really had an > urgent need for TDR. Occasionally I resonate stuff out with a <gasp> dip > meter. But even there it has happened that I didn't use for a while and > the battery oozed out. I also have this as a backup: > > http://oak.cats.ohiou.edu/~postr/bapix/Dip_59.htm Nice. And it refers to: http://bama.edebris.com/manuals/boonton/59/ which has the operator manual. I have the 59 - now I have the manual, too. :-) Thanks! Ed
From: JosephKK on 30 Sep 2009 22:42 On Tue, 29 Sep 2009 20:00:49 -0700, John Larkin <jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote: >On Tue, 29 Sep 2009 15:27:53 -0700, Joerg <invalid(a)invalid.invalid> >wrote: > >>John Larkin wrote: >>> On Tue, 29 Sep 2009 12:53:36 -0700, Joerg <invalid(a)invalid.invalid> >>> wrote: >>> >>>> John Larkin wrote: >>>>> On Tue, 29 Sep 2009 13:34:14 -0400, Phil Hobbs >>>>> <pcdhSpamMeSenseless(a)electrooptical.net> wrote: >>>>> >>>>>> John Larkin wrote: >>>>>>> On Tue, 29 Sep 2009 09:25:15 -0700, Joerg <invalid(a)invalid.invalid> >>>>>>> wrote: >>>>>>> >>>>>>>> John Larkin wrote: >>>>>>>>> On Mon, 28 Sep 2009 17:43:22 -0700, Joerg <invalid(a)invalid.invalid> >>>>>>>>> wrote: >>>>>>>>> >>>>>>>>>> John Larkin wrote: >>>>>>>>>>> On Mon, 28 Sep 2009 20:05:23 -0400, Phil Hobbs >>>>>>>>>>> <pcdhSpamMeSenseless(a)electrooptical.net> wrote: >>>>>>>>>>> >>>>>>>>>>>> John Fields wrote: >>>>>>>>>>>>> On Mon, 28 Sep 2009 10:25:05 -0700, John Larkin >>>>>>>>>>>>> <jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote: >>>>>>>>>>>>> >>>>>>>>>>>>>> On Sat, 26 Sep 2009 17:58:27 -0700, Archimedes' Lever >>>>>>>>>>>>>> <OneBigLever(a)InfiniteSeries.Org> wrote: >>>>>>>>>>>>>> >>>>>>>>>>>>>>> On Sat, 26 Sep 2009 16:52:40 -0700, John Larkin >>>>>>>>>>>>>>> <jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote: >>>>>>>>>>>>>>> >>>>>>>>>>>>>>>> On Sat, 26 Sep 2009 17:28:50 -0400, "Michael A. Terrell" >>>>>>>>>>>>>>>> <mike.terrell(a)earthlink.net> wrote: >>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>> John Larkin wrote: >>>>>>>>>>>>>>>>>> There's the slideback technique: drive a comparator with RF on one >>>>>>>>>>>>>>>>>> side, DC feedback on the other. Tease the DC appropriately. >>>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>>> I once made a slideback sampling oscilloscope, using tunnel diodes, as >>>>>>>>>>>>>>>>>> my EE senior project. I won an award and had to attend a dreadful IEEE >>>>>>>>>>>>>>>>>> chapter banquet and repeat it to a bunch of old-fart power engineers >>>>>>>>>>>>>>>>>> who didn't understand a word I said. I described the slideback >>>>>>>>>>>>>>>>>> sampling scope in this ng some years back and a certain party loved >>>>>>>>>>>>>>>>>> the idea so much he later decided that he'd invented it himself. >>>>>>>>>>>>>>>>> <http://store.americanmicrosemiconductor.com/diodes-tunnel-diodes.html> >>>>>>>>>>>>>>>> TDs are insanely expensive nowadays, ballpark $100. I used to get them >>>>>>>>>>>>>>>> for a couple bucks from Allied. The fabrication process is insane, and >>>>>>>>>>>>>>>> nobody ever modernized it. >>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>> There are some more modern planar germanium back diodes, essentially >>>>>>>>>>>>>>>> low Ip tunnel diodes, but they're RF detectors, useless for switching. >>>>>>>>>>>>>>>> Pity, I used to like tunnel diodes. >>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>> http://aeroflex.com/AMS/Metelics/pdfiles/MBD_Series_Planar_Back_Tunnel_Diodes.pdf >>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>> John >>>>>>>>>>>>>>> Try PiN diodes then. >>>>>>>>>>>>>> For what? Certainly not switching, amplifying, oscillating, detection, >>>>>>>>>>>>>> or mixing. >>>>>>>>>>>>> --- >>>>>>>>>>>>> Re. switching, From: >>>>>>>>>>>>> >>>>>>>>>>>>> http://en.wikipedia.org/wiki/PIN_diode >>>>>>>>>>>>> >>>>>>>>>>>>> "Under zero or reverse bias, a PIN diode has a low capacitance. The low >>>>>>>>>>>>> capacitance will not pass much of an RF signal. Under a forward bias of >>>>>>>>>>>>> 1 mA, a typical PIN diode will have an RF resistance of about 1 ohm, >>>>>>>>>>>>> making it a good RF conductor. Consequently, the PIN diode makes a good >>>>>>>>>>>>> RF switch." >>>>>>>>>>>>> --- >>>>>>>>>>>> Good, but not fast. PIN diodes specialize in having a lot of stored >>>>>>>>>>>> charge, so that the signal current can be quite a bit larger than the DC >>>>>>>>>>>> current without causing excessive distortion. >>>>>>>>>>>> >>>>>>>>>>>> Cheers >>>>>>>>>>>> >>>>>>>>>>>> Phil Hobbs >>>>>>>>>>> PINs stop behaving like PINs at low frequencies, too. So they don't >>>>>>>>>>> make useful wideband switches. >>>>>>>>>>> >>>>>>>>>> Got to watch the carrier lifetime. The lower the bottom of your spectrum >>>>>>>>>> and the higher the RF current, the longer its carrier lifetime must be. >>>>>>>>>> I found PIN diodes to be great and most of all cheap variable >>>>>>>>>> attenuators as well as switched. Designed in tons of them. >>>>>>>>>> >>>>>>>>>> >>>>>>>>>>> But I meant active switching when I was referring to a TD. A TD would >>>>>>>>>>> *generate* a fast step from an arbitrarily slow drive. >>>>>>>>>>> >>>>>>>>>> I've drooled over SRDs all my life and every time I wanted to buy one I >>>>>>>>>> either couldn't have one or it was outlandishly expensive. Guess >>>>>>>>>> avalanching is the only game in town and if you want avalanche-rated >>>>>>>>>> then a bone-simple BJT can easily shoot up to twenty bucks. >>>>>>>>> SRDs aren't hard to get. MA/Com has distributor parts, under a buck. >>>>>>>>> M-Pulse and Metelics are good about samples. If you want a few, send >>>>>>>>> me a SASE. >>>>>>>>> >>>>>>>>> Oh, here it is... >>>>>>>>> >>>>>>>>> 229-1769 DIO SRD 30V SOT23 150PS MA44769 1PF >>>>>>>>> >>>>>>>>> MA44769-287 PENSTOCK >>>>>>>>> >>>>>>>>> Price 58 cents in small quantities. >>>>>>>>> >>>>>>>>> They also have MA44767-287, 600 ps risetime, a little easier to drive >>>>>>>>> because it stores more charge. >>>>>>>>> >>>>>>>>> These make nice edge generators and frequency multipliers. I have a >>>>>>>>> rubidium clock that generates the 6.3846826128 GHz frequency from a 10 >>>>>>>>> MHz rock with an absurdly small number of cheap parts. >>>>>>>>> >>>>>>>> Thanks, John! That's a decent price. And thanks for the SASE offer, but >>>>>>>> maybe I'll combine that with a beer at Zeitgeist when I get down there :-) >>>>>>> Well, drop in. We have a zillion exotic parts in stock. And the >>>>>>> quality of Z's burgers has improved radically lately. Only biker bar I >>>>>>> know of with Chimay on tap. >>>>>>> >>>>>>>> As a kid I grew up in Europe and back then such exotic parts were very >>>>>>>> hard to find over there, even at hamfests. >>>>>>> We were lucky. Tons of exotic surplus gear, lots of old teevees, >>>>>>> Allied and Lafayette and Fair Radio Sales mail-order available to >>>>>>> anyone, local distributors for over-the-counter transistors and >>>>>>> 10-turn pots and such... the counter guys gave me more parts than I >>>>>>> ever paid for. I made a deal with my parents to dump my allowance in >>>>>>> favor of a revolving credit account with Allied, so I could just order >>>>>>> stuff. I made spending money fixing radios and TVs. >>>>>>> >>>>>>> John >>>>>>> >>>>>> Still not as good as now. I just bought an excellent-condition HP 8568B >>>>>> spectrum analyzer for $900. About 2 cents on the dollar. So far this >>>>>> year I've bought test equipment that would have cost way over $100000 >>>>>> new, for probably $4k altogether. Amazing. >>>>>> >>>>>> Cheers >>>>>> >>>>>> Phil Hobbs >>>>> And I'm looking at, theoretically, a quarter million dollars worth of >>>>> sampling heads over there on my shelf. This is an amazing time to >>>>> start a niche business, or even an exotic hobby. >>>>> >>>> Is there anything available at reasonable cost that does zippy sampling >>>> without needing a Goliath of a scope attached to it? >>> >>> Not really. The 5000 and 7000 series scopes had sampling plugins - I >>> have a bunch, and they're dirt cheap now - but they were pretty bad >>> compared to the superb 11801-series stuff. >>> >> >>There is an 11802 on Ebay right now for $1k but untested, "powers up". >>Thing is, I haven't gotten much more space here. A sampler for the 7704 >>over here would be nice. What is so bad with S-4 and 7S11? Ok, the >>25psec risetime doesn't quite rival your gear but for most stuff that >>should do. > >That stuff works, but it's not as quantitative as the later gear. And >TDR is a fabulous thing to have, and the TDR on the 7-series stuff is >really mediocre. > >Isn't this beautiful? > >ftp://jjlarkin.lmi.net/Z250A.jpg >ftp://jjlarkin.lmi.net/Z250_TDR.jpg > >(TDR of the test trace, J28 to J29) > >> >> >>> There are some little USB samplers, but they're very expensive. >>> >> >>Probably not much of a market anymore and the TDR guys in the field >>dont' need a precision under a foot to figure where they have to drop >>the bucket of their Kubota. > >Too much cheap surplus stuff on ebay, too. I'd love to do a cheapish >USB TDR, but there's probably no good market. > >John John L, Jeorg: I am in the market for (in no particular order) a fast analog scope maybe a TEK 2465B. I could use an 11801/11802 with a few heads good to say 6 GHz, and some probes. A decent freq/interval counter. A 5-1/2 digit multimeter (with 4 terminal ohms, and true rms ac measurements up to 100 KHz). And an AM/FM modulatable function/sweep generator up to 20 MHz. Except for the good scopes, this is high hobbyist to low end or mid-range lab stuff. 20 years away from the lab and i don't remember what is good stuff any more. The stuff must be functional, but 20+ year old stuff is quite acceptable. For computer interactivity i expect to buy/use USB to GPIB converter(s). Serial is acceptable as well. My proper email address is in the headers. I have an objection to dealing with e-prey or preypal myself.
From: JosephKK on 30 Sep 2009 23:53 On Fri, 25 Sep 2009 09:13:53 -0700, Jim Thompson <To-Email-Use-The-Envelope-Icon(a)My-Web-Site.com> wrote: >Anyone have clever ideas for rectifying a 500MHz sine wave, amplitude >say 50mV to 500mV peak-to-peak? > >Half wave is OK. > >1mV accuracy is needed :-( > >Process is X-Fab XB06. > >Thanks! > > ...Jim Thompson Read the whole thread. I can see how your approach will work. Just the same, i would consider range switching. Most anything like analog switches or transmission gate won't cut it for rectification at those levels and frequency. My idea is to use samplers, use a six or 8 way group of samplers and get a total sample rate of 3 or 4 GS/s. Then average/analyze the ratios of the six/eight sampler outputs. Maybe synchronizing them signal to be measured would be worthwhile. This could give you as much as 50 MHz detector bandwidth with the resolution of 2% or so.
From: Jan Panteltje on 1 Oct 2009 09:05
On a sunny day (Wed, 30 Sep 2009 18:50:54 -0700 (PDT)) it happened osr(a)uakron.edu wrote in <4630805d-0746-46cd-b971-56acd9059212(a)w36g2000yqm.googlegroups.com>: >I've had fun with two hobbyist concepts: > >The Lambda Diode: > >http://users.tpg.com.au/users/ldbutler/NegResDipMeter.htm Nice! |