On Sun, 31 Jan 2016 14:44:28 -0600, "Tim Williams" <tiwill@seventransistorlabs.com> wrote:>"John Larkin" wrote in message >news:79bsabhfcqnegk82mtt708to85n21jbadg@4ax.com... >> What's the frequency and the bandwidth requirement? >> >> Regular low-frequency circuit topologies generally don't scale well >> into RF amps. > > >At least 100MHz, prefer "as much as possible". Without going out of my >way for, like, PHEMTs and shit I mean. ;-) > >Gain at least 20dB, but that can be spread over several stages, and >anyway, 1W input is pretty easily solved with a handful of other things (a >2N3866 would do that handily). > >Some other junkbox items include video output transistors (something like >100V 200mA, fT's from 200MHz to ~1.2GHz), with the downside that I'll need >to parallel several to achieve full output power. Parallel may be an >advantage. I can use smaller 'input' side transistors for individual >cascodes, and just wire all their outputs in parallel. Maybe even with >some phase shift to get a distributed amplifier going. > >Transformer coupling is okay, and I may just do so, to solve the PNP >problem (and to keep R_L in the sweet spot for whatever transistors I've >grabbed). In that case, LF limit is <= 100kHz, which should be easily >enough handled by a little wire on a pot core or something. I'm not >worried about that. > >Also tempted to play with some of those SuperJunction MOSFETs I have on >hand. 600V 5A and ~10pF above 50V is fun. They are apparently free from >2nd breakdown, too. Downsides are the relatively low dissipation for the >ratings, and the still rather massive Ciss making them hard to drive >(like, you'd need a magnified cascode to do it). > >This will be nothing like a "regular low-frequency circuit"; feedback will >be local. Especially if I'm doing something distributed... the phase >shift can be expected to be several cycles by cutoff. No GNFB reasonable >there. > >I'm also assuming a 50 ohm load (with whatever matching as needed), so I >don't much care about Zo. I suppose the ideal solution would use a mix of >local NFB to get an active 50 ohms Zo (until cutoff, where the peaking >coils take over), but that's optional. > >TimThe real fork in the road is whether it needs to be wideband. A 100 MHz amp is a lot different from a DC-to-100 MHz amp. Narrowband, you can tune out parasitics, which is how people get tubes and mosfets to work at a GHz. Wideband gets more interesting. What's it for? -- John Larkin Highland Technology, Inc lunatic fringe electronics
Cascode substitutions
Started by ●January 31, 2016
Reply by ●January 31, 20162016-01-31
Reply by ●January 31, 20162016-01-31
Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> Wrote in message:> On 01/31/2016 03:42 PM, bitrex wrote: > >>> >>> You've already said that you're a moral relativist, so there's no use >>> appealing to your better nature. ;) >> >> True, but it doesn't seem to stop people from trying... > > A lot of moral relativists are much better than their principles, and I > hope you're one. The principles themselves are so bad that it's > scarcely possible for someone to be worse. > > I try very hard to deal only with straight shooters. I've had to fire > customers who weren't, and I certainly wouldn't knowingly work with > someone whose moral ideas were controlled by his own convenience. > > Cheers > > Phil Hobbs >The weird thing is, regardless of my moral relativism, I seem to generally behave in a moral fashion. But I couldn't tell you exactly why. Guess I had those messages drilled into me real good and I can't handle the cognitive dissonance. I catch spiders and gently put them outside. But given some of the horrible experiences I've had in life, I find it very difficult to believe that morality is anything innate or universal. At the end of the day, the Universe doesn't care. -- ----Android NewsGroup Reader---- http://usenet.sinaapp.com/
Reply by ●January 31, 20162016-01-31
Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> Wrote in message:> On 01/31/2016 03:42 PM, bitrex wrote: > >>> >>> You've already said that you're a moral relativist, so there's no use >>> appealing to your better nature. ;) >> >> True, but it doesn't seem to stop people from trying... > > A lot of moral relativists are much better than their principles, and I > hope you're one. The principles themselves are so bad that it's > scarcely possible for someone to be worse. > > I try very hard to deal only with straight shooters. I've had to fire > customers who weren't, and I certainly wouldn't knowingly work with > someone whose moral ideas were controlled by his own convenience. >Articles like this: http://www.salvomag.com/new/articles/salvo1/koukl.php Are dead from the start, because they don't define the terms. What are the definitions of your "axioms" of right and wrong, good and evil? The problem could be argued to be one of categorization. Essentialism is at the core of many "moral" problems such as abortion, animal rights, and end of life issues. When does life begin, and when does it end? Nature will never give you a clear cut answer to these questions. Saying a fetus is a "person" after 3 months, and not before, is ridiculous. Why is a human embryo consisting of a couple cells, with no capacity for pain or fear, afforded more protection than an adult animal, which can clearly suffer? Outside a few fringe circles Americans seem to have no problem slaughtering the latter beings in their millions, every year. There are cultures and religions, however, that take great offense to that (Jaanism, etc.) Are they "wrong"? Humans want to box things into neat bins. It's a natural predispositon, since not being able to quickly answer yes or no to whether something is dangerous or not would get us killed real quick 100k years ago. But science has shown us over and over again that Nature at a more fundamental level doesn't really operate that way. Check out the "firewall paradox" in quantum cosmology if you want a real trip. -- ----Android NewsGroup Reader---- http://usenet.sinaapp.com/
Reply by ●January 31, 20162016-01-31
bitrex <bitrex@de.lete.earthlink.net> Wrote in message:> Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> Wrote in message: >> On 01/31/2016 03:42 PM, bitrex wrote: >> >>>> >>>> You've already said that you're a moral relativist, so there's no use >>>> appealing to your better nature. ;) >>> >>> True, but it doesn't seem to stop people from trying... >> >> A lot of moral relativists are much better than their principles, and I >> hope you're one. The principles themselves are so bad that it's >> scarcely possible for someone to be worse. >> >> I try very hard to deal only with straight shooters. I've had to fire >> customers who weren't, and I certainly wouldn't knowingly work with >> someone whose moral ideas were controlled by his own convenience. >> > Check out the "firewall paradox" in quantum cosmology if you want > a real trip. >Put briefly, it appears that to truly resolve the black hole information paradox, as observers we can't all even inhabit the same Universe. Maybe there isn't even any "observer" at all. -- ----Android NewsGroup Reader---- http://usenet.sinaapp.com/
Reply by ●January 31, 20162016-01-31
On 1/31/2016 4:31 PM, John Larkin wrote:> On Sun, 31 Jan 2016 14:58:48 -0500, mixed nuts > <melopsitticus@undulatus.budgie> wrote: >> On 1/31/2016 12:26 PM, bitrex wrote: >>> John Larkin <jjlarkin@highlandtechnology.com> Wrote in message: >>>> On Sun, 31 Jan 2016 05:34:23 -0600, "Tim Williams" >>>> <tiwill@seventransistorlabs.com> wrote: >>>> >>>>> Designing an RF amplifier. Concept is, high power, complementary cascodes >>>>> for the output stage (with heavy class A use, but being PP, class AB is an >>>>> option). 50 ohm output, direct drive, say 10W level. >>>>> >>>>> I happen to have a complementary pair that's not too slow (2SC2690A and >>>>> 2SA1220A), and I'd like to maximize the bandwidth around that. The NPN >>>>> side is fine, I have a 30V, 1A, 2GHz transistor that would pair very well >>>>> with it. Don't have any such thing for the PNP side. >>>>> >>>>> So, what if I fake a PNP, by wrapping, say, a BFT92 around the NPN? >>>>> http://seventransistorlabs.com/Images/Sziklai_Cascode.png >>>>> That'd be Q1 = BFT92, Q2 = 2SC4821, Q3 = 2SA1220A, and resistors for >>>>> flavor, but probably roughly representative. (Ground wouldn't actually be >>>>> ground-ground, but probably something like +40V, and "+12V" would be >>>>> +45V.) >>>>> >>>>> The combination is still fast... ah, but Sziklai connections have a >>>>> propensity for oscillation all their own, let alone in a cascode, plus >>>>> whatever other machinations I might have for feedback around the thing. >>>>> Game killer? >>>>> >>>>> The other option would be folded cascode, which is understandably rather >>>>> wasteful for a power stage! >>>>> >>>>> Tim >>>> >>>> What's the frequency and the bandwidth requirement? >>>> >>>> Regular low-frequency circuit topologies generally don't scale well >>>> into RF amps. >>>> >>> >>> Does anyone use that admittance/Z parameter matrix stuff for RF >>> amp design/stability analysis that I've read about in books like >>> "Intro to RF Design" by Wes Hayward, or do they just mess with it >>> in Spice and are then like "eh works well enough ship >>> it" >> >> Not so much anymore - it's all wired into RF design packages - some >> bloody expensive, a couple free. SPICE input files can be used - if you >> have a well characterized SPICE model, the simulation engine will >> understand it. S-Parameter simulations are the norm. Generally, these >> packages will work with MATLAB/Octave, VHDL, Verilog... or have >> something similar built in - lots of post processing and modeling options. >> >> SPICE sucks for modeling transmission lines. The RF/Microwave packages >> will work directly with dimensions and materials - just plug in the >> numbers or click on a library definition. Life is good. > > Think so? I Spice txlines all the time, and the results seem to be > realistic.It can be done - and I did it when there were no other options with realistic results. The problem comes, for example, when you're dealing with a dispersive structure over a wide bandwidth with frequency dependent losses. With SPICE you have to generate a lumped element equivalent circuit which may consist of 20 sections (to get good numbers over 4 octaves). Each section is a 3 element LP but the L is a set of inductors and resistors to produce a piecewise approximation to skin effect (fractional pole expansion - see http://www.designers-guide.org/Modeling/ind.pdf ). Farkin' tedious, especially when you have 2 balanced lines broken up into 6 subsections that you want to vary length to tune to one frequency, null another, and couple a signal in/out. So, being able to drop the pieces onto a schematic, plug in dielectric constants, physical dimensions and conductivities, select a well tested model for the dispersive component and go is much nicer. This is an xml definition for a one section of a coupled microstrip filter: <MCOUPLED MS1 1 410 840 -26 37 0 0 "Subst1" 1 "384um" 1 "5.24mm" 1 "482um" 1 "Kirschning" 0 "Kirschning" 0 "26.85" 0> "Subst1" further expands in a piece of 30 mil thick Rogers Duroid 5880. "Kirschning" is a recognized model for dispersive microstrip. The numbers are entered into a dialog box or pulled in from a library. Less pain. -- Grizzly H.
Reply by ●January 31, 20162016-01-31
On Sun, 31 Jan 2016 16:43:39 -0500 (EST), bitrex <bitrex@de.lete.earthlink.net> wrote:>Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> Wrote in message: >> On 01/31/2016 03:42 PM, bitrex wrote: >> >>>> >>>> You've already said that you're a moral relativist, so there's no use >>>> appealing to your better nature. ;) >>> >>> True, but it doesn't seem to stop people from trying... >> >> A lot of moral relativists are much better than their principles, and I >> hope you're one. The principles themselves are so bad that it's >> scarcely possible for someone to be worse. >> >> I try very hard to deal only with straight shooters. I've had to fire >> customers who weren't, and I certainly wouldn't knowingly work with >> someone whose moral ideas were controlled by his own convenience. >> >> Cheers >> >> Phil Hobbs >> > >The weird thing is, regardless of my moral relativism, I seem to > generally behave in a moral fashion. But I couldn't tell you > exactly why. Guess I had those messages drilled into me real good > and I can't handle the cognitive dissonance. I catch spiders and > gently put them outside. > >But given some of the horrible experiences I've had in life, I > find it very difficult to believe that morality is anything > innate or universal. At the end of the day, the Universe doesn't > care.Morality is like, is part of, consciousness. If God permeates the universe, He permeates our DNA too. We don't just follow the rules, we are part of the rules. Pragmatically, societies that play fair do better. In my experience, honest and generous people usually come out ahead (exemping the occasional talented sociopath.) Good electronic design requires a lot of honesty and a good helping of generosity. It's a team sport. -- John Larkin Highland Technology, Inc lunatic fringe electronics
Reply by ●January 31, 20162016-01-31
On 01/31/2016 04:43 PM, bitrex wrote:> Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> Wrote in > message: >> On 01/31/2016 03:42 PM, bitrex wrote: >> >>>> >>>> You've already said that you're a moral relativist, so there's >>>> no use appealing to your better nature. ;) >>> >>> True, but it doesn't seem to stop people from trying... >> >> A lot of moral relativists are much better than their principles, >> and I hope you're one. The principles themselves are so bad that >> it's scarcely possible for someone to be worse. >> >> I try very hard to deal only with straight shooters. I've had to >> fire customers who weren't, and I certainly wouldn't knowingly work >> with someone whose moral ideas were controlled by his own >> convenience. >> >> Cheers >> >> Phil Hobbs >> > > The weird thing is, regardless of my moral relativism, I seem to > generally behave in a moral fashion. But I couldn't tell you exactly > why. Guess I had those messages drilled into me real good and I > can't handle the cognitive dissonance. I catch spiders and gently put > them outside.Which does make you better than your principles, at least part of the time. You might want to inquire--as a matter of some urgency--where that higher moral law (for that is what it is) that judges your intentions comes from.> > But given some of the horrible experiences I've had in life, I find > it very difficult to believe that morality is anything innate or > universal. At the end of the day, the Universe doesn't care.One of the many problems with that view is the immense agreement between people of all eras and all places on what is and is not OK. There are disagreements at the edges, e.g. whether you have to be unselfish towards everybody or just your own family/tribe/clan/nation, or whether you can have one wife or five. But I claim that you can't actually imagine a society that sincerely admired people who ran away in battle, or who double-crossed all their friends, for instance. Cheers Phil Hobbs -- Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC Optics, Electro-optics, Photonics, Analog Electronics 160 North State Road #203 Briarcliff Manor NY 10510 hobbs at electrooptical dot net http://electrooptical.net
Reply by ●January 31, 20162016-01-31
John Larkin <jjlarkin@highlandtechnology.com> Wrote in message:> On Sun, 31 Jan 2016 16:43:39 -0500 (EST), bitrex > <bitrex@de.lete.earthlink.net> wrote: > >>Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> Wrote in message: >>> On 01/31/2016 03:42 PM, bitrex wrote: >>> >>>>> >>>>> You've already said that you're a moral relativist, so there's no use >>>>> appealing to your better nature. ;) >>>> >>>> True, but it doesn't seem to stop people from trying... >>> >>> A lot of moral relativists are much better than their principles, and I >>> hope you're one. The principles themselves are so bad that it's >>> scarcely possible for someone to be worse. >>> >>> I try very hard to deal only with straight shooters. I've had to fire >>> customers who weren't, and I certainly wouldn't knowingly work with >>> someone whose moral ideas were controlled by his own convenience. >>> >>> Cheers >>> >>> Phil Hobbs >>> >> >>The weird thing is, regardless of my moral relativism, I seem to >> generally behave in a moral fashion. But I couldn't tell you >> exactly why. Guess I had those messages drilled into me real good >> and I can't handle the cognitive dissonance. I catch spiders and >> gently put them outside. >> >>But given some of the horrible experiences I've had in life, I >> find it very difficult to believe that morality is anything >> innate or universal. At the end of the day, the Universe doesn't >> care. > > Morality is like, is part of, consciousness. If God permeates the > universe, He permeates our DNA too. We don't just follow the rules, we > are part of the rules.God can't save you. She's out shopping. -- ----Android NewsGroup Reader---- http://usenet.sinaapp.com/
Reply by ●January 31, 20162016-01-31
Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> Wrote in message:> On 01/31/2016 04:43 PM, bitrex wrote: >> Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> Wrote in >> message: >>> On 01/31/2016 03:42 PM, bitrex wrote: >>> >>>>> >>>>> You've already said that you're a moral relativist, so there's >>>>> no use appealing to your better nature. ;) >>>> >>>> True, but it doesn't seem to stop people from trying... >>> >>> A lot of moral relativists are much better than their principles, >>> and I hope you're one. The principles themselves are so bad that >>> it's scarcely possible for someone to be worse. >>> >>> I try very hard to deal only with straight shooters. I've had to >>> fire customers who weren't, and I certainly wouldn't knowingly work >>> with someone whose moral ideas were controlled by his own >>> convenience. >>> >>> Cheers >>> >>> Phil Hobbs >>> >> >> The weird thing is, regardless of my moral relativism, I seem to >> generally behave in a moral fashion. But I couldn't tell you exactly >> why. Guess I had those messages drilled into me real good and I >> can't handle the cognitive dissonance. I catch spiders and gently put >> them outside. > > Which does make you better than your principles, at least part of the > time. You might want to inquire--as a matter of some urgency--where > that higher moral law (for that is what it is) that judges your > intentions comes from. > >> >> But given some of the horrible experiences I've had in life, I find >> it very difficult to believe that morality is anything innate or >> universal. At the end of the day, the Universe doesn't care. > > One of the many problems with that view is the immense agreement between > people of all eras and all places on what is and is not OK. There are > disagreements at the edges, e.g. whether you have to be unselfish > towards everybody or just your own family/tribe/clan/nation, or whether > you can have one wife or five. > > But I claim that you can't actually imagine a society that sincerely > admired people who ran away in battle, or who double-crossed all their > friends, for instance. >Well, yeah, a society made completely of atavistic sociopaths wouldn't last very long. But then that means at some level morality is something that must evolve parallel to humans living in societies at all, which means it must stem from a particular society. i.e. it's not a universal innate quality of humans. Maybe it might be better to say that certain humans have an innate _capability_ for morality, in the same sense that every human born with certain physical and mental characteristics has the capability to be an astronaut, given the right environment and the right life circumstances. I'm pretty sure that some people (fortunately a small amount) are born rotten. They come that way from the factory and nothing can change it. I definitely don't belive in any innate "goodness" of humans, or that we're all made in God's image. -- ----Android NewsGroup Reader---- http://usenet.sinaapp.com/
Reply by ●January 31, 20162016-01-31
Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> Wrote in message:> On 01/31/2016 04:43 PM, bitrex wrote: >> Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> Wrote in >> message: >>> On 01/31/2016 03:42 PM, bitrex wrote: >>> >>>>> >>>>> You've already said that you're a moral relativist, so there's >>>>> no use appealing to your better nature. ;) >>>> >>>> True, but it doesn't seem to stop people from trying... >>> >>> A lot of moral relativists are much better than their principles, >>> and I hope you're one. The principles themselves are so bad that >>> it's scarcely possible for someone to be worse. >>> >>> I try very hard to deal only with straight shooters. I've had to >>> fire customers who weren't, and I certainly wouldn't knowingly work >>> with someone whose moral ideas were controlled by his own >>> convenience. >>> >>> Cheers >>> >>> Phil Hobbs >>> >> >> The weird thing is, regardless of my moral relativism, I seem to >> generally behave in a moral fashion. But I couldn't tell you exactly >> why. Guess I had those messages drilled into me real good and I >> can't handle the cognitive dissonance. I catch spiders and gently put >> them outside. > > Which does make you better than your principles, at least part of the > time. You might want to inquire--as a matter of some urgency--where > that higher moral law (for that is what it is) that judges your > intentions comes from. >A higher moral law giving humans free will, but then essentially revoking it in the same breath by dictating that there will be horrible consequences for not using it in the appropriate fashion, and then giving the players no option whether the wish to play or not (being born) seems like a rather perverse game. You might sometimes question the sanity of whatever moral authority wants to run that one. But yeah, I'm pretty sure that if there was a Son of God, Christ was a good candidate. Tell people to love each other, get nailed to a cross? Sure. Sounds like just the sort of thing people would do. -- ----Android NewsGroup Reader---- http://usenet.sinaapp.com/
