On a sunny day (Sun, 7 May 2017 20:56:49 +0100) it happened "Kevin Aylward" <kevinRemovAT@kevinaylward.co.uk> wrote in <5qmdnXfOYaWf4ZLEnZ2dnUU7-YfNnZ2d@giganews.com>:>I wrote this over 15 yeas ago: > >http://www.kevinaylward.co.uk/gr/emc2/emc2.html > >again, now pay attention to the statement just before the summary.Interesting, a short wile ago I was discussing time change in gravity. As you know clocks slow down in a stronger gravitational field. The discussion went .. well anyways I pointed out that time' is defined as definition of second is: " the duration of 9 192 631 770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the caesium 133 atom " (from https://en.wikipedia.org/wiki/Second). I mentioned I have this Rubidium frequency standard in the lab, and wondered if anybody had brought that AND the caesium clock up to space, and looked if there was a difference, and mathematicians could have a field day if there was or was not, as it tells something about the change in electron orbits in a changing gravitational field. But I guess the audience ... Never mind. As with all theories none is complete, we are not more than an ant creeping up a wall, no clue about the ideas of the architect that build the wall. And I am not even religious. Einstein's is then by definition an approximation, sort of holds true. It is also a mathematical trap. Without a 'mechanism' it is no good (mechanism for gravity) but Newton already noticed that (lack of mechanism). But way OT for tronix perhaps.>Address my actual points first. Like, > >1 What can NOT be done in spice that MUST be done using S parametersI clearly stated I do not use S params, and neither do I use spice a lot, in fact almost never. Even worse, I do not use mplab to program PICs. or some silly IDE to write C code. Not even so much to program FPGA (closest to ASICs I have ever been). But everything always works. Added several new features today to a big project in C. Part of it is in asm.>2 Explain how one does phase noise, distortion, bias design and power >optimisation using just S parameters. > >I want to know how *you* design high performance, competitive, oscillators >using only S parameters. > >I have told you how I do it.Words are only words, and where IS it then ?>-- Kevin Aylward >http://www.anasoft.co.uk - SuperSpice >http://www.kevinaylward.co.uk/ee/index.html > >
How to determine Zin, Yout for RF transistor, from A parameters
Started by ●May 6, 2017
Reply by ●May 7, 20172017-05-07
Reply by ●May 7, 20172017-05-07
On a sunny day (Sun, 7 May 2017 20:55:15 +0100) it happened "Kevin Aylward" <kevinRemovAT@kevinaylward.co.uk> wrote in <BIqdnXfG6Yo55pLEnZ2dnUU7-UPNnZ2d@giganews.com>:> yer good old JFET > |-------------- choke--- + 12 > ------------>| | >| | |-- | >| === C | | >L |------------| === >| === [ ] | decoupling >| | 2C | 1k | > ---------------------------------- GND > >Ho hummm... > >That is not an oscillator.Really... I does oscillate here, been doing that for decades.>It, may be in another universe,Ah, I am on earth, where are you? ;-)>a part of $5 dick >tracy walky talki for children.4 letter words, ho!>>Worked for me. > > >What is its phase noise? >What is is stability over temperature and power supply variations? >How many will be in spec out of a million made? >What is its spec? >What's its frequency sensitivity to load?Good question.>.... > >>You never actually build any RF did you? > >I don't build anything today, I haven't for many years. I modied my Marshall >amp a while back though. It had a || loop for the effects. Ho humm...Does it use vacuum tubes?>However, I do have an OCXO asic in production that runs up to 100MHz, has a >few ppb stability, and flat band phase noise approaching -165db, in a very >small package.Very impressive,. -165 dB wonder how you measure that. What do you use it for, QAM 65535? Or QAM 32 bits?>How about you?I dunno, I am on earth.
Reply by ●May 7, 20172017-05-07
On Sun, 7 May 2017 20:58:11 +0100, "Kevin Aylward" <kevinRemovAT@kevinaylward.co.uk> wrote:>"Jim Thompson" wrote in message >news:toeugctj4jg00n4nh8j7olqupvadn7p78m@4ax.com... > >On Sat, 6 May 2017 19:26:59 -0400, bitrex ><bitrex@de.lete.earthlink.net> wrote: > >>On 05/06/2017 05:18 PM, Cursitor Doom wrote: >>> On Sat, 06 May 2017 14:12:38 -0400, bitrex wrote: >>> >>>> If you know how to use a Smith chart you can design an impedance >>>> matching network for same amp in about 5 minutes that would take you the >>>> better part of an hour to grunge thru on paper >>> >>> Well no shit, Sherlock. >>> >> >>The grandparent poster may not have. > >>That's a remarkably ignorant statement. During my youth slide rules >>and Smith Charts were taught in high school and college. > >Indeed, and we no longer use slide rules. > >Although, Jim, being that you are somewhat mature now, it may be that you >can't avoid relapsing to your childhood...Perhaps. I still doodle on paper before constructing a Spice simulation.> >>For the first 15 years out of school there were no Spice simulators. > >Indeed, and we now do use SpiceYep, but see above.> > >-- Kevin Aylward >http://www.anasoft.co.uk - SuperSpice >http://www.kevinaylward.co.uk/ee/index.html...Jim Thompson -- | James E.Thompson | mens | | Analog Innovations | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | STV, Queen Creek, AZ 85142 Skype: skypeanalog | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at http://www.analog-innovations.com | 1962 | Thinking outside the box... producing elegant solutions. "It is not in doing what you like, but in liking what you do that is the secret of happiness." -James Barrie
Reply by ●May 7, 20172017-05-07
On Sun, 07 May 2017 21:04:14 +0100, JM <dontreplytothis173@gmail.com> wrote:>On 07/05/2017 20:52, Kevin Aylward wrote: >> Analog ones are more challenging, but essentially, the chief reason, > >And oranges are much better than apples. > > >So edifying >:-} ...Jim Thompson -- | James E.Thompson | mens | | Analog Innovations | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | STV, Queen Creek, AZ 85142 Skype: skypeanalog | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at http://www.analog-innovations.com | 1962 | Thinking outside the box... producing elegant solutions. "It is not in doing what you like, but in liking what you do that is the secret of happiness." -James Barrie
Reply by ●May 7, 20172017-05-07
"Cursitor Doom" <curd@notformail.com> wrote in message news:oemv17$d0o$8@dont-email.me...>> Measured: >> https://www.seventransistorlabs.com/ClassD1/Images/ > ClassD_GateWavScope.jpg > > > FFS, Tim. Your scope's screen is so scratched it's hard to tell the > traces from the scars!Well, no, those were photoshopping artifacts actually. I wasn't as good with it back then. :^) Tim -- Seven Transistor Labs, LLC Electrical Engineering Consultation and Contract Design Website: http://seventransistorlabs.com
Reply by ●May 7, 20172017-05-07
On Sun, 07 May 2017 07:40:32 -0700, John Larkin <jjlarkin@highlandtechnology.com> wrote:>On Sun, 7 May 2017 10:47:22 -0000 (UTC), Cursitor Doom ><curd@notformail.com> wrote: > >>On Sat, 06 May 2017 16:09:02 -0700, John Larkin wrote: >> >>> How do you know what to simulate? Just plunking parts on a screen and >>> running Spice only works for very simple circuits. >> >>You will have just incurred Kev's wrath with this remark, John. Expect to >>be beaten into a pulp by attrition. > >Maybe SuperSpice accepts a short verbal description of what you want, >and how much it should cost.The "DWIM" switch.
Reply by ●May 7, 20172017-05-07
On Sun, 7 May 2017 20:52:06 +0100, "Kevin Aylward" <kevinRemovAT@kevinaylward.co.uk> wrote:>"Jan Panteltje" wrote in message news:oekvo1$jak$1@news.datemas.de... > >On a sunny day (Sat, 6 May 2017 11:24:14 -0500) it happened "Tim Williams" ><tiwill@seventransistorlabs.com> wrote in <oekt4r$aoj$1@dont-email.me>: > >>Sadly, a ton of transistors just don't give that info. >> >>Some don't even give s-params, or their LF equivalents (junction C's, >>internal resistances, etc.). >> >>The OP wasn't exactly specific... >> >>It's nice to just keep shopping for a part that does, but if this is going >>deep into the rarefied territory of RF (the OP wasn't exactly specific >>:) ), >>you can be SOL very easily. >> >>Tim >> >>-- >>Seven Transistor Labs, LLC >>Electrical Engineering Consultation and Contract Design >>Website: http://seventransistorlabs.com >> >> >>"Kevin Aylward" <kevinRemovAT@kevinaylward.co.uk> wrote in message >>news:pKqdnS_JAfH24JDEnZ2dnUU7-L3NnZ2d@giganews.com... >>> wrote in message >>> news:394a6d1b-52b4-4864-845a-517591c881b3@googlegroups.com... >>> >>>>Could some RGF/microwave guru on this newsgroup >>>>please help ? I am looking at the datasheet for >>>>a ONSemi RF transistor, with the S parameters >>>>listed for various frequencies. What would be >>>>a quick and easy(that I can code as a simple >>>>C program) way to convert these to the >>>>corresponding Zin and Yout. Thanks in >>>>advance for your hints/suggestions. >>> >>> Why? >>> >>> Try and find the spice model, and do everything in spice. >>> >>> One of the remain reasons for stuff like S parameters, was simply that it >>> was easier to measure than other ones in the distant past. Its simply all >>> irrelevant now. We have simulation tools. >>> >>> S parameters are way too limiting for optimum design. Usually, they are >>> only specified for one or a few current/voltage sets, and they are only >>> useful at all for linear analysis. This is a disaster for decent optimum >>> production design.s >>> >>> S parameter design for transistor circuits is, essentially, a legacy >>> claptrap rut, that many just can't get out off. >>> >>> A good spice model will allow you do accurately design over the whole >>> range of operating currents and voltages including the required >>> transient, >>> real world large signals that the circuit is actually being used for. >>> > > >>These days people run simulations, and really they remind me of NASA, >>in the sense that when NASA detects a new planet, >.... >>...AND on top of that, if you have your spice working, you have NOTHING, >>it is all illusion like that movie, and ... > >Unfortunately, you have absolutely no idea whatsoever about modern >electronic asic design, and I mean that you are completely clueless on that >matter. Your implication that one has to piss about on a breadboard after >designing in the simulation universe, is wrong. Period.There is a big difference between chip and board level design. The models for board level design are _really_ bad. It's not unusual to find you're breaking several laws of the universe. ;-) Chip level models *have* to be good, or as you point out, nothing will ever work.> >Its simply fact that 100,000s of ascis with up to billions of transistors >are designed entirely in simulation, and a very large % of them work >correctly, first time.If you designed a board with billions of transistors, using only SPICE, I doubt it would work, too.>I have given a lecture on this several time before in this NG. Look it up. >Some processes cost 1/2 million dollars for a set of masks. Do you really >think that a company is going throw that money down the toilet?Halfa megabuck is nothing. We were up to $2M for a full set, ten years ago.>Analog ones are more challenging, but essentially, the chief reason, imo, >why an analog asic don't work first pass, is because the designer wasn't the >full shilling, not that there is any issue with designing in the virtual >world.Again, board <> ASIC
Reply by ●May 7, 20172017-05-07
On Monday, 8 May 2017 01:52:15 UTC+1, k...@notreal.com wrote:> Halfa megabuck is nothing.not in my universe NT
Reply by ●May 8, 20172017-05-08
On 2017-05-06 05:50, dakupoto@gmail.com wrote:> Could some RGF/microwave guru on this newsgroup > please help ? I am looking at the datasheet for > a ONSemi RF transistor, with the S parameters > listed for various frequencies. What would be > a quick and easy(that I can code as a simple > C program) way to convert these to the > corresponding Zin and Yout. Thanks in > advance for your hints/suggestions. >Since no one took the trouble to simply reply to your question, here we go. The S11 parameter is the input reflection coefficient. It's just a different way to represent input impedance. S11 is in fact what you would measure across the arms of a Wheatstone bridge with the relevant impedance in one of the arms and Z0 = 50 Ohm resistors in all the others. Converting, Zin = Z0*(1+S11)/(1-S11). The same conversion applies to S22 and Zout. Yout=1/Zout. Bear in mind that these are linearized parameters of a basically non-linear device at specific bias conditions and with a specific excitation level. All complex number math, naturally. Jeroen Belleman
Reply by ●May 8, 20172017-05-08
On Monday, May 8, 2017 at 10:43:22 AM UTC+3, Jeroen Belleman wrote:> On 2017-05-06 05:50, dakupoto@gmail.com wrote: > > Could some RGF/microwave guru on this newsgroup > > please help ? I am looking at the datasheet for > > a ONSemi RF transistor, with the S parameters > > listed for various frequencies. What would be > > a quick and easy(that I can code as a simple > > C program) way to convert these to the > > corresponding Zin and Yout. Thanks in > > advance for your hints/suggestions. > > > > Since no one took the trouble to simply reply to your > question, here we go. > > The S11 parameter is the input reflection coefficient. > It's just a different way to represent input impedance. > S11 is in fact what you would measure across the > arms of a Wheatstone bridge with the relevant impedance > in one of the arms and Z0 = 50 Ohm resistors in all the > others. Converting, Zin = Z0*(1+S11)/(1-S11). > > The same conversion applies to S22 and Zout. Yout=1/Zout. > > Bear in mind that these are linearized parameters of > a basically non-linear device at specific bias conditions > and with a specific excitation level. > > All complex number math, naturally. > > Jeroen BellemanFor an unilateral transistor i.e. S12 nonzero, the formulae are a bit more complicated: Zin = Z0 * ((1+S11)*(1-S22)+S12*S21) / ((1-S11)*(1-S22)-S12*S21) Yout = 1/Z0 * ((1+S11)*(1-S22)+S12*S21) / ((1+S11)*(1+S22)-S12*S21) One obtains those from signal graph analysis, or (as I did) by copying from Pozar's book. Regards, Mikko
