Rectify 500MHz Small Signal
in [Design]
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From: John Larkin on 29 Sep 2009 18:00 On Tue, 29 Sep 2009 21:59:41 +0200, Rene Tschaggelar <none(a)none.net> wrote: >John Larkin wrote: >> On Tue, 29 Sep 2009 11:22:32 +0200, Rene Tschaggelar <none(a)none.net> >> wrote: >> >>> Jim Thompson 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 >>> There are zero-bias diodes available up to at >>> least Xband (10GHz). They have a sensitivity >>> of in the order of -55dBm >>> >>> I recently got some for 30 bucks each. >>> >>> Rene >> >> Try Skyworks. Similar parts for under a buck. >> >> John >> > >Thanks John, >we then took some M/A-Com parts. It was to be mounted >into a waveguide in the DO119 case. I'll have a look >at skyworks for next time. They deliver through BFI >Optilas and possibly digikey. > >Rene They probably don't have the pill-packaged parts. Most of their stuff is surface mount. We use an SC-79 (practically invisible) 0.2 pF low-barrier schottky of theirs, SMS7621-079, 38 cents each. Maybe you can drop a little antenna + diode pc board into the waveguide? John
From: Joerg on 29 Sep 2009 18:27 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. > 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. > Pumping scope is good for you. > "Room service, good evening. What would you like to order?" .... "Send up some more room, please." -- Regards, Joerg http://www.analogconsultants.com/ "gmail" domain blocked because of excessive spam. Use another domain or send PM.
From: John Larkin on 29 Sep 2009 23:00 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
From: John Larkin on 29 Sep 2009 23:02 On Tue, 29 Sep 2009 13:29:48 -0400, Phil Hobbs <pcdhSpamMeSenseless(a)electrooptical.net> wrote: >Jan Panteltje wrote: >> On a sunny day (Tue, 29 Sep 2009 09:34:08 -0700) it happened Joerg >> <invalid(a)invalid.invalid> wrote in <7ier86F30e1vkU1(a)mid.individual.net>: >> >>>> UJTs are cool. >>> >>> Well, yeah, but you probably lived in the Netherlands as a kid. You guys >>> had dump handelaars and all sorts of electronics places. UJTs were >>> unobtanium in Germany. Once in a while we'd mount a car and head over >>> the border. But since I was a kid back then and didn't have my own car >>> I'd have to hitch a ride. We usually split the cost for gas and then it >>> was affordable for everyone, but you needed a whole day. >>> >>> Later I lived in Zuid Limburg and with a stiff bicycle ride you could >>> haul stuff home from the surplus dealer in Margraten. Wrecked many >>> baggage racks that way, plus some chains, axles and so on. And found out >>> the hard way that bicycle brakes don't work so good with 50 pounds of >>> stuff on the back. >> >> Still widely available, I used the 2N2646: >> http://nl.farnell.com/unijunction-transistors-ujt > >I like PUTs for things like laser interlocks. Unlike ICs, I know >exactly how they'll behave in fault conditions, which matters a lot. >Relays are good too. > >Cheers > >Phil Hobbs I had a lot of fun with PUTs. They would drive TTL directly from that upper gate thingie. John
From: Rene Tschaggelar on 30 Sep 2009 06:00
John Larkin wrote: > On Tue, 29 Sep 2009 21:59:41 +0200, Rene Tschaggelar <none(a)none.net> > wrote: > >> John Larkin wrote: >>> On Tue, 29 Sep 2009 11:22:32 +0200, Rene Tschaggelar <none(a)none.net> >>> wrote: >>> >>>> Jim Thompson 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 >>>> There are zero-bias diodes available up to at >>>> least Xband (10GHz). They have a sensitivity >>>> of in the order of -55dBm >>>> >>>> I recently got some for 30 bucks each. >>>> >>>> Rene >>> Try Skyworks. Similar parts for under a buck. >>> >>> John >>> >> Thanks John, >> we then took some M/A-Com parts. It was to be mounted >> into a waveguide in the DO119 case. I'll have a look >> at skyworks for next time. They deliver through BFI >> Optilas and possibly digikey. >> >> Rene > > They probably don't have the pill-packaged parts. Most of their stuff > is surface mount. We use an SC-79 (practically invisible) 0.2 pF > low-barrier schottky of theirs, SMS7621-079, 38 cents each. > > Maybe you can drop a little antenna + diode pc board into the > waveguide? > > John > Thanks John, That I would do in a design of mine, but I'm rather reluctant when I repair a commercial machine. Rene |