On Sat, 17 Mar 2018 09:40:55 -0700, Jim Thompson <To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> wrote:>On Fri, 16 Mar 2018 23:57:38 -0700 (PDT), dakupoto@gmail.com wrote: > >>On Friday, March 16, 2018 at 10:05:40 PM UTC+5:30, Jim Thompson wrote: >>> On Fri, 16 Mar 2018 04:50:54 -0700 (PDT), dakupoto@gmail.com wrote: >>> >>> >On Friday, March 16, 2018 at 3:42:04 AM UTC+5:30, Jim Thompson wrote: >>> [snip] >>> >> >> Schematic? What does "wideband" mean? fL, fH, dB's? >>> >> >> >>> >> >> ...Jim Thompson >>> >> [snip] >>> >> > >>> [snip] >>> >> > >>> >> >Any hints/suggestions would be very helpful. >>> >> >Thanks in advance. >>> >> >>> >> Gozinta/gozouta specification? You're exhibiting the standard failure >>> >> here of thinking you can force what you think the solution should be >>> >> rather than specifying the desired results... sort like the "Searching >>> >> for an Op-Amp" fiasco >:-} >>> >> >>> >> (I actually have symbols in my spice library: gozinta, gozouta, and >>> >> gozbi... prettied-up _small_ port symbols ;-) >>> >> >>> [snip] >>> >>> NGspice, HSpice noted. LTspice requires all kinds of extra steps to >>> get to a numerically analyzable set of data points >>> >>> Unless HSpice has been recently neutered, I'd hazard a guess that it's >>> .PRINT statement will produce a table in the .OUT file that can pasted >>> into Excel or a curve-fitting program (which is what I mostly use it >>> for... for behavioral modeling ;-) >>> >>> > >>> >I am not forcing anything on anyone. Please read my previous response to your previous message. >>> >>> Then I missed that post... perhaps during my surgery yesterday? >>> >>> I'd like an answer to "What does "wideband" mean? fL, fH, dB's?" >>> >>> If your desired LP corner is > 2*pi*Rload/Lload you've got problems, >>> if < 2*pi*Rload/Lload, piece-a-cake. >>> >>> A definitive statement of the problem will produce definitive answers, >>> otherwise blather and bloviations >:-} >>> >>> ...Jim Thompson >[snip] >> >>So, let us start with the LP corner < 2.0*PI*RLoad*Lload, >> >>What would be the solution ? > >I'll post later today. Hope I got that right for frequency... bit >foggy-brained after the surgery... it's _lower_ than the natural >corner of Rload and LLoad ;-) > > ...Jim ThompsonMy website is down for maintenance, so I've tried dropbox: <https://www.dropbox.com/s/jmwp76qi8chyvs5/DakupotoMatching.zip?dl=0> Hope that works! Let me ponder... there might be an easy way to export a netlist from LTspice into NGspice. If not, I believe I've seen original flavor PSpice Schematics available without the PSpice simulator. ...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 | Understanding is a fountain of life to one who has it, But the instruction of fools is folly. Proverbs 16:22
Broadband impedance matching of series RL load
Started by ●March 14, 2018
Reply by ●March 17, 20182018-03-17
Reply by ●March 19, 20182018-03-19
On Saturday, March 17, 2018 at 9:24:08 PM UTC+5:30, John Larkin wrote:> On Sat, 17 Mar 2018 00:09:28 -0700 (PDT), dakupoto@gmail.com wrote: > > >On Friday, March 16, 2018 at 8:27:40 PM UTC+5:30, John Larkin wrote: > >> On Fri, 16 Mar 2018 04:12:22 -0700 (PDT), dakupoto@gmail.com wrote: > >> > >> >On Thursday, March 15, 2018 at 9:27:10 PM UTC+5:30, John Larkin wrote: > >> >> On Thu, 15 Mar 2018 05:30:38 -0700 (PDT), dakupoto@gmail.com wrote: > >> >> > >> >> >On Thursday, March 15, 2018 at 5:15:38 AM UTC+5:30, Jim Thompson wrote: > >> >> >> On Tue, 13 Mar 2018 23:39:57 -0700 (PDT), dakupoto@gmail.com wrote: > >> >> >> > >> >> >> >Could some electronics guru please help ? I am running some SPICE > >> >> >> >simulations on wideband impedance matching of the following setup. > >> >> >> >The source and load resistances are equal > >> >> >> >The source is a pure resistor > >> >> >> >Yhe load consists of a resistor(same value as source resistor) and > >> >> >> >a series inductor > >> >> >> >The matching network is a 6th order low pass filter with a > >> >> >> >series inductor as the last element. > >> >> >> >The RMS input power and the RMS output power are measured. > >> >> >> >The ratio RMS output power/RMS input power is very low, indicating > >> >> >> >poor matching and large invident signal reflection. How would the > >> >> >> >load inductor be bullified in a physically realizable way ? All > >> >> >> >hints/suggestions are welcome. Thanks in advance. > >> >> >> > > >> >> >> > > >> >> >> > >> >> >> Schematic? What does "wideband" mean? fL, fH, dB's? > >> >> >> > >> >> >> ...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 | > >> >> >> > >> >> >> It's what you learn, after you know it all, that counts. > >> >> > > >> >> >The SPICE netlist is listed below: > >> >> >Low pass filter impedance matching > >> >> >* Identical load source resistance > >> >> >* and series load inductor > >> >> > > >> >> >.PARAMS FREQ=3.453144e+08 LLIM=1.726572e+07 HLIM=6.043003e+08 AMPL=10 > >> >> > > >> >> >.SUBCKT LPFILT 1 2 > >> >> >* 1 IN > >> >> >* 2 OUT > >> >> >C1 1 0 2.353875e-10 > >> >> >L2 1 3 6.431530e-10 > >> >> >C3 3 0 8.787569e-10 > >> >> >L4 3 4 8.791318e-10 > >> >> >C5 4 0 6.441774e-10 > >> >> >L6 4 2 2.367870e-10 > >> >> >.ENDS > >> >> > > >> >> >* COMMENT OUT TRANSIENT ANALYSIS > >> >> >* TO RUN AC ANALYSIS AND VICE-VERSA > >> >> > > >> >> >LLOAD 6 7 1.200000e-08 > >> >> >LCOMP 5 6 1.772026e-11 > >> >> >RSRC 1 2 50.000000 > >> >> >RLOAD 7 0 50.000000 > >> >> >XLP 3 4 LPFILT > >> >> >VTST0 2 3 DC 0.0 AC 0.0 > >> >> >VTST1 4 5 DC 0.0 AC 0.0 > >> >> > > >> >> >* FOR TRANSIENT ANALYSIS > >> >> >VSIG 1 0 DC 0.005 SIN(0 {AMPL} {FREQ} 0 0 0) > >> >> >* FOR AC(SMALL SIGNAL) ANALYSIS > >> >> >VSIG 1 0 DC 0.005 AC {AMPL}) > >> >> > > >> >> >.OPTIONS METHOD=GEAR NOPAGE RELTOL=1m MINBREAK=5ps > >> >> >.IC > >> >> >.TRAN 75.0ns 500.0us 50.0ns UIC > >> >> >* INPUT/SOURCE SIDE > >> >> >.PRINT TRAN V(3) I(VTST0) > >> >> >* LOAD/OUTPUT SIDE > >> >> >.PRINT TRAN V(4) I(VTST1) > >> >> > > >> >> >.AC LIN 20000 {LLIM} {HLIM} > >> >> >.PRINT AC V(5) > >> >> >** FOR REFLECTION COEFFICIENT ETC., > >> >> >.PRINT AC V(2) > >> >> >.END > >> >> > > >> >> >Any hints/suggestions would be very helpful. > >> >> >Thanks in advance. > >> >> > >> >> Can you post a visible schematic? > >> >> > >> >> I still don't know what you are trying to do. > >> >> > >> >> I've done some work lately on one-end-reflectionless lowpass filters, > >> >> based on Jeroen's concepts. Mini-Circuits has some interesting new > >> >> symmetric filters, both-ends-reflectionless. > >> >> > >> >> > >> >> -- > >> >> > >> >> John Larkin Highland Technology, Inc > >> >> > >> >> lunatic fringe electronics > >> > > >> >I am afraid I do not have a visible schematic. I use HSpice at work, and Ngspice at home, both of which use the text input. It is sometimes bothersome to enter a new large netlist, but > >> >editing is very easy. > >> > >> Just a sketch would help. I don't know what you are trying to do. > >> > >> LT Spice lets you draw a schematic instantly. Typing (and reading!) > >> netlists is really old-fashioned. > >> > >> > >> > >> > >> -- > >> > >> John Larkin Highland Technology, Inc > >> > >> lunatic fringe electronics > > > >The setup is simple : > >A signal source feeds a low pass ladder matching network, e.g., of order 6. The source impedance is purely resistive (NO source reactance). The load is a resistor in series with an inductor. The load and source resistors have the same value > >So how do I compensate for the frequency dependent load inductor ? > > I think the answer is trivial, but if you refuse to show a sketch, I > refuse to talk about it. > > > -- > > John Larkin Highland Technology, Inc > > lunatic fringe electronicsThe solution is indeed trivial -- Zobel network. Funny thing is that I had workrf on a similar problem about three years ago, derived the simple expressions for this simple but very useful sub-circuit, and then completely forgotten about it. The frequency response of a Zobel network is flat over any frequency range of choice, thereby "converting" a series R-L or series R-C load to a resistor.
Reply by ●March 19, 20182018-03-19
On Thursday, March 15, 2018 at 11:01:09 AM UTC+5:30, Jasen Betts wrote:> On 2018-03-14, dakupoto@gmail.com <dakupoto@gmail.com> wrote: > > Could some electronics guru please help ? I am running some SPICE > > simulations on wideband impedance matching of the following setup. > > The source and load resistances are equal > > The source is a pure resistor > > Yhe load consists of a resistor(same value as source resistor) and > > a series inductor > > The matching network is a 6th order low pass filter with a > > series inductor as the last element. > > The RMS input power and the RMS output power are measured. > > The ratio RMS output power/RMS input power is very low, indicating > > poor matching and large invident signal reflection. How would the > > load inductor be bullified in a physically realizable way ? All > > hints/suggestions are welcome. Thanks in advance. > > are you looking for a Zobel Network? > https://en.wikipedia.org/wiki/Zobel_network > > -- > This email has not been checked by half-arsed antivirus softwareThanks for jogging my memory. I had worked on a similar design issue about three years ago, derived the simple expressions for the Zobel network, and then completely forgotten about it.
Reply by ●March 19, 20182018-03-19
On Saturday, March 17, 2018 at 10:30:00 PM UTC+5:30, Phil Hobbs wrote:> On 03/17/18 02:57, dakupoto@gmail.com wrote: > > On Friday, March 16, 2018 at 10:05:40 PM UTC+5:30, Jim Thompson wrote: > >> On Fri, 16 Mar 2018 04:50:54 -0700 (PDT), dakupoto@gmail.com wrote: > >> > >>> On Friday, March 16, 2018 at 3:42:04 AM UTC+5:30, Jim Thompson wrote: > >> [snip] > >>>>>> Schematic? What does "wideband" mean? fL, fH, dB's? > >>>>>> > >>>>>> ...Jim Thompson > >>>> [snip] > >>>>> > >> [snip] > >>>>> > >>>>> Any hints/suggestions would be very helpful. > >>>>> Thanks in advance. > >>>> > >>>> Gozinta/gozouta specification? You're exhibiting the standard failure > >>>> here of thinking you can force what you think the solution should be > >>>> rather than specifying the desired results... sort like the "Searching > >>>> for an Op-Amp" fiasco >:-} > >>>> > >>>> (I actually have symbols in my spice library: gozinta, gozouta, and > >>>> gozbi... prettied-up _small_ port symbols ;-) > >>>> > >> [snip] > >> > >> NGspice, HSpice noted. LTspice requires all kinds of extra steps to > >> get to a numerically analyzable set of data points > >> > >> Unless HSpice has been recently neutered, I'd hazard a guess that it's > >> .PRINT statement will produce a table in the .OUT file that can pasted > >> into Excel or a curve-fitting program (which is what I mostly use it > >> for... for behavioral modeling ;-) > >> > >>> > >>> I am not forcing anything on anyone. Please read my previous response to your previous message. > >> > >> Then I missed that post... perhaps during my surgery yesterday? > >> > >> I'd like an answer to "What does "wideband" mean? fL, fH, dB's?" > >> > >> If your desired LP corner is > 2*pi*Rload/Lload you've got problems, > >> if < 2*pi*Rload/Lload, piece-a-cake. > >> > >> A definitive statement of the problem will produce definitive answers, > >> otherwise blather and bloviations >:-} > >> > >> ...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 | > >> > >> Understanding is a fountain of life to one who has it, > >> But the instruction of fools is folly. Proverbs 16:22 > > > > So, let us start with the LP corner < 2.0*PI*RLoad*Lload, > > > > What would be the solution ? > > > > There's a tradeoff between the log of the return loss and > bandwidth--it's a theorem of Bode's, so of course it's called the > Fano-Bode limit. See e.g. > > http://www.ece.ucsb.edu/~long/ece145a/zmatch.pdf > > Cheers > > Phil Hobbs > -- > Dr Philip C D Hobbs > Principal Consultant > ElectroOptical Innovations LLC / Hobbs ElectroOptics > Optics, Electro-optics, Photonics, Analog Electronics > Briarcliff Manor NY 10510 > > http://electrooptical.net > http://hobbs-eo.comSo true. In fact, all approaches to broadband impedance matching are governed by the Bode-Fano inequalities. The solution that I re-discovered( I had worked on a very similar problem about three years ago) is the Zobel network, that effectively "converts" a series R-C or series R-L load to a resistor -- used to impedance match signals to gates of RF/microwave FETs.
Reply by ●March 19, 20182018-03-19
On 03/19/2018 02:16 AM, dakupoto@gmail.com wrote:> On Saturday, March 17, 2018 at 10:30:00 PM UTC+5:30, Phil Hobbs wrote: >> On 03/17/18 02:57, dakupoto@gmail.com wrote: >>> On Friday, March 16, 2018 at 10:05:40 PM UTC+5:30, Jim Thompson wrote: >>>> On Fri, 16 Mar 2018 04:50:54 -0700 (PDT), dakupoto@gmail.com wrote: >>>> >>>>> On Friday, March 16, 2018 at 3:42:04 AM UTC+5:30, Jim Thompson wrote: >>>> [snip] >>>>>>>> Schematic? What does "wideband" mean? fL, fH, dB's? >>>>>>>> >>>>>>>> ...Jim Thompson >>>>>> [snip] >>>>>>> >>>> [snip] >>>>>>> >>>>>>> Any hints/suggestions would be very helpful. >>>>>>> Thanks in advance. >>>>>> >>>>>> Gozinta/gozouta specification? You're exhibiting the standard failure >>>>>> here of thinking you can force what you think the solution should be >>>>>> rather than specifying the desired results... sort like the "Searching >>>>>> for an Op-Amp" fiasco >:-} >>>>>> >>>>>> (I actually have symbols in my spice library: gozinta, gozouta, and >>>>>> gozbi... prettied-up _small_ port symbols ;-) >>>>>> >>>> [snip] >>>> >>>> NGspice, HSpice noted. LTspice requires all kinds of extra steps to >>>> get to a numerically analyzable set of data points >>>> >>>> Unless HSpice has been recently neutered, I'd hazard a guess that it's >>>> .PRINT statement will produce a table in the .OUT file that can pasted >>>> into Excel or a curve-fitting program (which is what I mostly use it >>>> for... for behavioral modeling ;-) >>>> >>>>> >>>>> I am not forcing anything on anyone. Please read my previous response to your previous message. >>>> >>>> Then I missed that post... perhaps during my surgery yesterday? >>>> >>>> I'd like an answer to "What does "wideband" mean? fL, fH, dB's?" >>>> >>>> If your desired LP corner is > 2*pi*Rload/Lload you've got problems, >>>> if < 2*pi*Rload/Lload, piece-a-cake. >>>> >>>> A definitive statement of the problem will produce definitive answers, >>>> otherwise blather and bloviations >:-} >>>> >>>> ...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 | >>>> >>>> Understanding is a fountain of life to one who has it, >>>> But the instruction of fools is folly. Proverbs 16:22 >>> >>> So, let us start with the LP corner < 2.0*PI*RLoad*Lload, >>> >>> What would be the solution ? >>> >> >> There's a tradeoff between the log of the return loss and >> bandwidth--it's a theorem of Bode's, so of course it's called the >> Fano-Bode limit. See e.g. >> >> http://www.ece.ucsb.edu/~long/ece145a/zmatch.pdf >> >> Cheers >> >> Phil Hobbs >> -- >> Dr Philip C D Hobbs >> Principal Consultant >> ElectroOptical Innovations LLC / Hobbs ElectroOptics >> Optics, Electro-optics, Photonics, Analog Electronics >> Briarcliff Manor NY 10510 >> >> http://electrooptical.net >> http://hobbs-eo.com > > So true. In fact, all approaches to broadband impedance matching are governed by the Bode-Fano > inequalities. The solution that I re-discovered( > I had worked on a very similar problem about three > years ago) is the Zobel network, that effectively > "converts" a series R-C or series R-L load to a > resistor -- used to impedance match signals to > gates of RF/microwave FETs. >Yup, a 1-pole diplexer. There are more complicated ones. Cheers Phil Hobbs -- Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC / Hobbs ElectroOptics Optics, Electro-optics, Photonics, Analog Electronics Briarcliff Manor NY 10510 http://electrooptical.net https://hobbs-eo.com
