Rectify 500MHz Small Signal
in [Design]
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From: Jim Thompson on 26 Sep 2009 20:31 On Fri, 25 Sep 2009 16:41:08 -0700, Jim Thompson <To-Email-Use-The-Envelope-Icon(a)My-Web-Site.com> wrote: >On Fri, 25 Sep 2009 13:41:19 -0700, Joerg <invalid(a)invalid.invalid> >wrote: > >>Jim Thompson wrote: >>> Anyone have clever ideas for rectifying a 500MHz sine wave, amplitude >>> say 50mV to 500mV peak-to-peak? >>> >> >>Only 40dB dynamic range, that's easy. 500MHz is going to be the not so >>easy part. >> >> >>> Half wave is OK. >>> >>> 1mV accuracy is needed :-( >>> >>> Process is X-Fab XB06. >>> >> >>It's been almost 20 years since I did this (in hardware though) and I >>don't know the X-Fab process, but have you thought about successive >>detectors similar to what you'd find in a log amp chip? Basically a >>bunch of gain stages that each cover a small sliver of the dynamic range >>and then saturate, with the grand total being the summed outputs. > >I'm tending toward AC-coupling plus a DC restorer... to "rectify" ;-) > > ...Jim Thompson Now functioning, need to make the loop-gain track the set-point and it'll be a winner ;-) ...Jim Thompson -- | James E.Thompson, P.E. | mens | | Analog Innovations, Inc. | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | Phoenix, Arizona 85048 Skype: Contacts Only | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at http://www.analog-innovations.com | 1962 | Coming soon to the elementary school in your neighborhood... I pledge allegiance to Dear Leader Barack Hussein Obama and to the community organization for which he stands: one nation under ACORN, unchallengeable, with wealth redistribution and climate change for all.
From: Michael A. Terrell on 26 Sep 2009 20:48 John Larkin 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 I posted it so the next time someone shows up with a 40 year old design and wants a tunnel diode, people will know where to send them. :) They even have LM3909 LED flashers for $6 each: <http://store.americanmicrosemiconductor.com/lm3909n.html> :) -- You can't have a sense of humor, if you have no sense!
From: Archimedes' Lever on 26 Sep 2009 20:58 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.
From: Fred Bartoli on 28 Sep 2009 08:56 Jim Thompson a �crit : > On Sat, 26 Sep 2009 12:23:57 -0400, Phil Hobbs > <pcdhSpamMeSenseless(a)electrooptical.net> wrote: > >> Jim Thompson wrote: >>> On Sat, 26 Sep 2009 11:09:43 GMT, nico(a)puntnl.niks (Nico Coesel) >>> wrote: >>> >>>> Bill Sloman <bill.sloman(a)ieee.org> wrote: >>>> >>>>> On Sep 25, 6:13=A0pm, Jim Thompson <To-Email-Use-The-Envelope-I...(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. >>>>> Barrie Gilbert has had some ideas. His AD834 >>>>> >>>>> http://www.analog.com/static/imported-files/data_sheets/AD834.pdf >>>>> >>>>> could be used to square your 500MHz signal, which automatically >>>>> rectifies it, though it leaves you with a lot of 1GHz ripple. >>>>> >>>>> If you wanted to do something cuter, you could phase-lock a nominally >>>>> 1GHz voltage-controlled logic level oscillator to the 500MHz signal, >>>>> and use it to generate two 500MHz signals mutually in quadrature - >>>>> nominally square waves, but at least with well-defined amplitudes, and >>>>> form in-phase and quadrature products. >>>>> >>>>> In a second order phase-locked loop, the quadrature output is >>>>> integrated to control the VCO such that the quadrature output is >>>>> precisely in quadrature with the incoming signal while the in-phase >>>>> output can be used to drive another product detector (aka multiplier) >>>>> whch gives you your rectified output. >>> Of course, see my WVB receiver (on my website, SED page), dated 1974. >>> >>> Just ducky when you have ample headroom (�5V supplies). I have a >>> single supply, minimum operating at +2.7V >>> >>> And Gilbert cells aren't all that accurate without lots of voltage an >>> on-chip trimming... I need accuracy at small signals. >>> >>>> How about a s&h, a 7 bit ADC, peak hold register and a 6 bit DAC? >>> Dream on ;-) >>> >>> ...Jim Thompson >> I like the electrical substitution idea already suggested (two diodes, >> drive one with DC to null out the signal from the other). How about >> ping-ponging a couple of them (say 75% duty cycle each), and measuring >> the offsets in between? You could measure the delta gain while they're >> both on (25% of the time) and the offsets when one or the other is off. >> With 75% duty cycle, they wouldn't ever be off together. >> >> Cheers >> >> Phil Hobbs > > I'm sort of "ping-ponging" (diode current) to get chip (and external) > temperatures. At 500MHz capacitance screws up rectification accuracy > at low levels (BiCMOS process). > Uh... Why don't you get it simple? Have your rectified level constant and a VCA in a feedback loop. -- Thanks, Fred.
From: John Larkin on 28 Sep 2009 13:25
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. There was a single-TD circuit that was an RF amp, a local oscillator, a mixer, and an IF amp. One TD and a couple of passives would make an FM transmitter. The beefier td's would make a voltage step with a 22 picosecond rise time... in 1964. John |