1 GHz synthesizer
in [Design]
|
From: Joel Koltner on 25 Feb 2010 14:42 "Jim Thompson" <To-Email-Use-The-Envelope-Icon(a)My-Web-Site.com> wrote in message news:eakdo5l3e5u671bc5oa0hqrvomsvpe54cs(a)4ax.com... > If no one comes forth with the actual paper in the next few days, > could you scan the snippet out of Hayward? Sure thing, will do. ---Joel
From: Phil Hobbs on 25 Feb 2010 15:18 On 2/25/2010 2:22 PM, Jim Thompson wrote: > On Thu, 25 Feb 2010 11:09:57 -0800 (PST), osr(a)uakron.edu wrote: > >> On Feb 25, 2:00 pm, o...(a)uakron.edu wrote: >>>> You want real fun? Try to align a 'Tubular Filter' without a network >>>> analyzer. >>> >>>> -- >>>> Greed is the root of all eBa >>> >>> That DOES NOT need to be the five hours it usually takes... >>> >>> On odd element microwave ones, short the Inner element. Adjust the >>> outer ones for SWR as desired, open up the inner one. >>> >>> Dishal's method.... The guy wrote a brilliant paper on it.. >>> >>> Steve >> >> Ah found it: >> >> Dishal, M., � Alignment and Adjustment of Synchronously Tuned Multiple- >> Resonant- >> Circuit Filters,� Elec. Commun., pp. 154-164, June, 1952. >> >> Also see Hayward, >> � Introduction to Radio Frequency Design,� ARRL, 1994, pp95-101. >> >> Steve >> > > Steve, Many of us have no access to either of those articles (I have > only 1981 and 1999 ARRL Handbooks). > > Can you post, or provide a link where IEEE rears their ugly head ?:-) > > Thanks! > > ...Jim Thompson Dishal works best with high-Q filters--it relies on the fact that detuned series sections look like open circuits and detuned parallel sections like shorts. You use a return-loss test setup, start from the end you're measuring, and get all the bumps in the calculated spots. Also it doesn't matter what you put in parallel with a series section--in the limit of high Q, you can't move its resonance. Works well for Q >~ 20 IME, but not as well at lower Q since the approximations don't hold as accurately. The thing to watch out for is the temptation to make the filter look nice but with a slightly too-narrow bandwidth: "There's no way to get there from here." Cheers Phil Hobbs -- Dr Philip C D Hobbs Principal ElectroOptical Innovations 55 Orchard Rd Briarcliff Manor NY 10510 845-480-2058 hobbs at electrooptical dot net http://electrooptical.net
From: Jim Thompson on 25 Feb 2010 15:20 On Thu, 25 Feb 2010 15:18:31 -0500, Phil Hobbs <pcdhSpamMeSenseless(a)electrooptical.net> wrote: >On 2/25/2010 2:22 PM, Jim Thompson wrote: >> On Thu, 25 Feb 2010 11:09:57 -0800 (PST), osr(a)uakron.edu wrote: >> >>> On Feb 25, 2:00 pm, o...(a)uakron.edu wrote: >>>>> You want real fun? Try to align a 'Tubular Filter' without a network >>>>> analyzer. >>>> >>>>> -- >>>>> Greed is the root of all eBa >>>> >>>> That DOES NOT need to be the five hours it usually takes... >>>> >>>> On odd element microwave ones, short the Inner element. Adjust the >>>> outer ones for SWR as desired, open up the inner one. >>>> >>>> Dishal's method.... The guy wrote a brilliant paper on it.. >>>> >>>> Steve >>> >>> Ah found it: >>> >>> Dishal, M., � Alignment and Adjustment of Synchronously Tuned Multiple- >>> Resonant- >>> Circuit Filters,� Elec. Commun., pp. 154-164, June, 1952. >>> >>> Also see Hayward, >>> � Introduction to Radio Frequency Design,� ARRL, 1994, pp95-101. >>> >>> Steve >>> >> >> Steve, Many of us have no access to either of those articles (I have >> only 1981 and 1999 ARRL Handbooks). >> >> Can you post, or provide a link where IEEE rears their ugly head ?:-) >> >> Thanks! >> >> ...Jim Thompson > >Dishal works best with high-Q filters--it relies on the fact that >detuned series sections look like open circuits and detuned parallel >sections like shorts. You use a return-loss test setup, start from the >end you're measuring, and get all the bumps in the calculated spots. > >Also it doesn't matter what you put in parallel with a series >section--in the limit of high Q, you can't move its resonance. > >Works well for Q >~ 20 IME, but not as well at lower Q since the >approximations don't hold as accurately. > >The thing to watch out for is the temptation to make the filter look >nice but with a slightly too-narrow bandwidth: "There's no way to get >there from here." > >Cheers > >Phil Hobbs I was thinking of using it for simulation tools ;-) ...Jim Thompson -- | James E.Thompson, CTO | 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 | I love to cook with wine. Sometimes I even put it in the food.
From: Phil Hobbs on 25 Feb 2010 15:24 On 2/25/2010 3:20 PM, Jim Thompson wrote: > On Thu, 25 Feb 2010 15:18:31 -0500, Phil Hobbs > <pcdhSpamMeSenseless(a)electrooptical.net> wrote: > >> On 2/25/2010 2:22 PM, Jim Thompson wrote: >>> On Thu, 25 Feb 2010 11:09:57 -0800 (PST), osr(a)uakron.edu wrote: >>> >>>> On Feb 25, 2:00 pm, o...(a)uakron.edu wrote: >>>>>> You want real fun? Try to align a 'Tubular Filter' without a network >>>>>> analyzer. >>>>> >>>>>> -- >>>>>> Greed is the root of all eBa >>>>> >>>>> That DOES NOT need to be the five hours it usually takes... >>>>> >>>>> On odd element microwave ones, short the Inner element. Adjust the >>>>> outer ones for SWR as desired, open up the inner one. >>>>> >>>>> Dishal's method.... The guy wrote a brilliant paper on it.. >>>>> >>>>> Steve >>>> >>>> Ah found it: >>>> >>>> Dishal, M., � Alignment and Adjustment of Synchronously Tuned Multiple- >>>> Resonant- >>>> Circuit Filters,� Elec. Commun., pp. 154-164, June, 1952. >>>> >>>> Also see Hayward, >>>> � Introduction to Radio Frequency Design,� ARRL, 1994, pp95-101. >>>> >>>> Steve >>>> >>> >>> Steve, Many of us have no access to either of those articles (I have >>> only 1981 and 1999 ARRL Handbooks). >>> >>> Can you post, or provide a link where IEEE rears their ugly head ?:-) >>> >>> Thanks! >>> >>> ...Jim Thompson >> >> Dishal works best with high-Q filters--it relies on the fact that >> detuned series sections look like open circuits and detuned parallel >> sections like shorts. You use a return-loss test setup, start from the >> end you're measuring, and get all the bumps in the calculated spots. >> >> Also it doesn't matter what you put in parallel with a series >> section--in the limit of high Q, you can't move its resonance. >> >> Works well for Q>~ 20 IME, but not as well at lower Q since the >> approximations don't hold as accurately. >> >> The thing to watch out for is the temptation to make the filter look >> nice but with a slightly too-narrow bandwidth: "There's no way to get >> there from here." >> >> Cheers >> >> Phil Hobbs > > I was thinking of using it for simulation tools ;-) > > ...Jim Thompson If you already know where the section resonances should go, that'll work fine, although I'm not sure what problem you're trying to solve.... Generally what makes filter tuning hard is that you're adjusting L and C, whereas you really want to adjust f_0 and Q, and simulators don't have that problem. Cheers Phil Hobbs -- Dr Philip C D Hobbs Principal ElectroOptical Innovations 55 Orchard Rd Briarcliff Manor NY 10510 845-480-2058 hobbs at electrooptical dot net http://electrooptical.net
From: Jim Thompson on 25 Feb 2010 15:35
On Thu, 25 Feb 2010 15:24:11 -0500, Phil Hobbs <pcdhSpamMeSenseless(a)electrooptical.net> wrote: >On 2/25/2010 3:20 PM, Jim Thompson wrote: >> On Thu, 25 Feb 2010 15:18:31 -0500, Phil Hobbs >> <pcdhSpamMeSenseless(a)electrooptical.net> wrote: >> >>> On 2/25/2010 2:22 PM, Jim Thompson wrote: >>>> On Thu, 25 Feb 2010 11:09:57 -0800 (PST), osr(a)uakron.edu wrote: >>>> >>>>> On Feb 25, 2:00 pm, o...(a)uakron.edu wrote: >>>>>>> You want real fun? Try to align a 'Tubular Filter' without a network >>>>>>> analyzer. >>>>>> >>>>>>> -- >>>>>>> Greed is the root of all eBa >>>>>> >>>>>> That DOES NOT need to be the five hours it usually takes... >>>>>> >>>>>> On odd element microwave ones, short the Inner element. Adjust the >>>>>> outer ones for SWR as desired, open up the inner one. >>>>>> >>>>>> Dishal's method.... The guy wrote a brilliant paper on it.. >>>>>> >>>>>> Steve >>>>> >>>>> Ah found it: >>>>> >>>>> Dishal, M., � Alignment and Adjustment of Synchronously Tuned Multiple- >>>>> Resonant- >>>>> Circuit Filters,� Elec. Commun., pp. 154-164, June, 1952. >>>>> >>>>> Also see Hayward, >>>>> � Introduction to Radio Frequency Design,� ARRL, 1994, pp95-101. >>>>> >>>>> Steve >>>>> >>>> >>>> Steve, Many of us have no access to either of those articles (I have >>>> only 1981 and 1999 ARRL Handbooks). >>>> >>>> Can you post, or provide a link where IEEE rears their ugly head ?:-) >>>> >>>> Thanks! >>>> >>>> ...Jim Thompson >>> >>> Dishal works best with high-Q filters--it relies on the fact that >>> detuned series sections look like open circuits and detuned parallel >>> sections like shorts. You use a return-loss test setup, start from the >>> end you're measuring, and get all the bumps in the calculated spots. >>> >>> Also it doesn't matter what you put in parallel with a series >>> section--in the limit of high Q, you can't move its resonance. >>> >>> Works well for Q>~ 20 IME, but not as well at lower Q since the >>> approximations don't hold as accurately. >>> >>> The thing to watch out for is the temptation to make the filter look >>> nice but with a slightly too-narrow bandwidth: "There's no way to get >>> there from here." >>> >>> Cheers >>> >>> Phil Hobbs >> >> I was thinking of using it for simulation tools ;-) >> >> ...Jim Thompson > >If you already know where the section resonances should go, that'll work >fine, although I'm not sure what problem you're trying to solve.... >Generally what makes filter tuning hard is that you're adjusting L and >C, whereas you really want to adjust f_0 and Q, and simulators don't >have that problem. > >Cheers > >Phil Hobbs Every once in a while I have to demonstrate a filter made from RLC's (but in PSpice) that meets the clients needs. _Possibly_ this method will allow me to "fake" some real filters ;-) ...Jim Thompson -- | James E.Thompson, CTO | 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 | I love to cook with wine. Sometimes I even put it in the food. |