On Sat, 13 Oct 2012 00:01:00 +0200, Jeroen wrote:> On 2012-10-12 19:02, Tim Wescott wrote: >> On Fri, 12 Oct 2012 12:08:46 +0200, Jeroen Belleman wrote: >> >>> On 2012-10-12 11:04, Robert Baer wrote: >>>> Vladimir Vassilevsky wrote: >>>>> "Tim Wescott"<tim@seemywebsite.com> wrote: >>>>>> How commonly do you see PLL designs referred to as "type I", "type >>>>>> II", "type III", etc.? Do the terms make sense to you? >>>>> >>>>> IMO this terminology is used only in Gardner's book; there is no >>>>> universal >>>>> meaning. >>>>> It is about P, PI, or PII control loop. Remnants of old times, when >>>>> they used to mix the details of implementation with the type of the >>>>> transfer function. >>>>> >>>>>> I'm writing a report; don't want to either baffle with bullshit nor >>>>>> leave >>>>>> out handy terms... >>>>> >>>>> Since nobody is going to read it anyway, why would that matter? >>>>> >>>>> Vladimir Vassilevsky >>>>> DSP and Mixed Signal Consultant >>>>> www.abvolt.com >>>>> >>>>> >>>> Do not know but my wild uneducated guess is that "P" stands for >>>> regular feedback as in a standard op-amp circuit, "PI" stands for >>>> first derivative (eg: "P dot") and "PII" stands for second derivative >>>> (eg: "P double dot"). >>>> >>>> >>>> >>> 'I' stands for an Integral term, not a derivative one. >>> >>> I think that PLL designs should be classified by the number of >>> significant poles and zeroes of their transfer functions. This 'type' >>> business only introduces an extra layer of obscurity. >> >> Both the number of poles (order), and the number of nekkid integrators >> (type) have relevance in telling you how the loop is going to behave. > > Well yes, in essence that's what I said. We know what the poles and > zeroes do. Introducing superfluous terminology like 'type' does not make > it any clearer. I'd say: Drop the type.A type 0 loop can have a bazillion poles and still be type 0. A type 2 loop can have only two poles. Poles and type are _different_. -- My liberal friends think I'm a conservative kook. My conservative friends think I'm a liberal kook. Why am I not happy that they have found common ground? Tim Wescott, Communications, Control, Circuits & Software http://www.wescottdesign.com
PLL Terminology Question
Started by ●October 11, 2012
Reply by ●October 13, 20122012-10-13
Reply by ●October 13, 20122012-10-13
On Sat, 13 Oct 2012 00:09:54 +0200, Jeroen wrote:> On 2012-10-12 19:05, Tim Wescott wrote: >> On Fri, 12 Oct 2012 08:39:21 -0700, John Larkin wrote: >> >>> On Fri, 12 Oct 2012 10:39:14 -0400, Randy Yates >>> <yates@digitalsignallabs.com> wrote: >>> >>>> Tim Wescott <tim@seemywebsite.com> writes: >>>> >>>>> How commonly do you see PLL designs referred to as "type I", "type >>>>> II", "type III", etc.? Do the terms make sense to you? >>>>> >>>>> I'm writing a report; don't want to either baffle with bullshit nor >>>>> leave out handy terms... >>>> >>>> Hi Tim, >>>> >>>> We used to use those terms in the 80s in our antenna control systems >>>> at GTE Government Systems. If I remember correctly, the "number" >>>> refers to the number of integrators in the loop. >>>> >>>> I don't think they are used much today. >>> >>> The question then becomes whether you count the inherent VCO phase >>> integration as one of those integrators. >> >> For any control loop you pick a point in the loop and go around, >> counting integrators, until you get back to the same point. Because >> the VCO takes a voltage and turns it into a frequency (which is the >> integral of phase), > > Harumph! Flub, phase is the integral of frequency. But you know that, of > course.Blargh. Indeedie. -- My liberal friends think I'm a conservative kook. My conservative friends think I'm a liberal kook. Why am I not happy that they have found common ground? Tim Wescott, Communications, Control, Circuits & Software http://www.wescottdesign.com
Reply by ●October 13, 20122012-10-13
On 2012-10-12, Jim Thompson <To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> wrote:> > Poles are from Poland. What are zeroes? >Zeroes were manufactured by Mitsubishi. -- ⚂⚃ 100% natural --- news://freenews.netfront.net/ - complaints: news@netfront.net ---
Reply by ●October 13, 20122012-10-13
On 10/12/2012 12:42 PM, Jim Thompson wrote:> On Fri, 12 Oct 2012 09:29:55 -0700 (PDT), George Herold > <gherold@teachspin.com> wrote: > >> On Oct 11, 4:36 pm, Tim Wescott<t...@seemywebsite.com> wrote: >>> How commonly do you see PLL designs referred to as "type I", "type II", >>> "type III", etc.? Do the terms make sense to you? >>> >>> I'm writing a report; don't want to either baffle with bullshit nor leave >>> out handy terms... >>> >>> -- >>> My liberal friends think I'm a conservative kook. >>> My conservative friends think I'm a liberal kook. >>> Why am I not happy that they have found common ground? >>> >>> Tim Wescott, Communications, Control, Circuits& Softwarehttp://www.wescottdesign.com >> >> Nice thread, thanks Tim. >> >> I assume "Phaselock Techniques" by Flyod M. Gardener is the right >> book. (Making my Xmas wish list.) Any advantage of the third edition >> over the second? >> >> So in a type III system the error signal is integrated twice? >> Does anyone have an example where double integration is used? >> It doesn't have to be a PLL application any type of control loop would >> be fine. >> >> George H. > > The extra filter/integrator is usually placed above the zero dB > cross-over, just to reduce noise. > > ...Jim ThompsonNo, it's another lead-lag integrator, to reduce the static phase offset due to a frequency ramp to zero. Back in the all-analogue days, that sometimes mattered. 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 ●October 13, 20122012-10-13
Jasen Betts wrote:> > On 2012-10-12, Jim Thompson <To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> wrote: > > > > Poles are from Poland. What are zeroes? > > > > Zeroes were manufactured by Mitsubishi.And used to attack Pearl Harbor.
Reply by ●October 13, 20122012-10-13
On Sat, 13 Oct 2012 07:23:37 -0400, Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> wrote:>On 10/12/2012 12:42 PM, Jim Thompson wrote: >> On Fri, 12 Oct 2012 09:29:55 -0700 (PDT), George Herold >> <gherold@teachspin.com> wrote: >> >>> On Oct 11, 4:36 pm, Tim Wescott<t...@seemywebsite.com> wrote: >>>> How commonly do you see PLL designs referred to as "type I", "type II", >>>> "type III", etc.? Do the terms make sense to you? >>>> >>>> I'm writing a report; don't want to either baffle with bullshit nor leave >>>> out handy terms... >>>> >>>> -- >>>> My liberal friends think I'm a conservative kook. >>>> My conservative friends think I'm a liberal kook. >>>> Why am I not happy that they have found common ground? >>>> >>>> Tim Wescott, Communications, Control, Circuits& Softwarehttp://www.wescottdesign.com >>> >>> Nice thread, thanks Tim. >>> >>> I assume "Phaselock Techniques" by Flyod M. Gardener is the right >>> book. (Making my Xmas wish list.) Any advantage of the third edition >>> over the second? >>> >>> So in a type III system the error signal is integrated twice? >>> Does anyone have an example where double integration is used? >>> It doesn't have to be a PLL application any type of control loop would >>> be fine. >>> >>> George H. >> >> The extra filter/integrator is usually placed above the zero dB >> cross-over, just to reduce noise. >> >> ...Jim Thompson > >No, it's another lead-lag integrator, to reduce the static phase offset >due to a frequency ramp to zero. Back in the all-analogue days, that >sometimes mattered. > >Cheers > >Phil Hobbs...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.
Reply by ●October 13, 20122012-10-13
On Sat, 13 Oct 2012 07:23:37 -0400, Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> wrote:>On 10/12/2012 12:42 PM, Jim Thompson wrote: >> On Fri, 12 Oct 2012 09:29:55 -0700 (PDT), George Herold >> <gherold@teachspin.com> wrote: >> >>> On Oct 11, 4:36 pm, Tim Wescott<t...@seemywebsite.com> wrote: >>>> How commonly do you see PLL designs referred to as "type I", "type II", >>>> "type III", etc.? Do the terms make sense to you? >>>> >>>> I'm writing a report; don't want to either baffle with bullshit nor leave >>>> out handy terms... >>>> >>>> -- >>>> My liberal friends think I'm a conservative kook. >>>> My conservative friends think I'm a liberal kook. >>>> Why am I not happy that they have found common ground? >>>> >>>> Tim Wescott, Communications, Control, Circuits& Softwarehttp://www.wescottdesign.com >>> >>> Nice thread, thanks Tim. >>> >>> I assume "Phaselock Techniques" by Flyod M. Gardener is the right >>> book. (Making my Xmas wish list.) Any advantage of the third edition >>> over the second? >>> >>> So in a type III system the error signal is integrated twice? >>> Does anyone have an example where double integration is used? >>> It doesn't have to be a PLL application any type of control loop would >>> be fine. >>> >>> George H. >> >> The extra filter/integrator is usually placed above the zero dB >> cross-over, just to reduce noise. >> >> ...Jim Thompson > >No, it's another lead-lag integrator, to reduce the static phase offset >due to a frequency ramp to zero. Back in the all-analogue days, that >sometimes mattered. > >Cheers > >Phil HobbsIn _modern_ times. I've not heard that before and I'm wa-a-a-ay older than you. Analog phase detectors locked at 90�. Although you seem actually to be implying more loop gain?? ...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.
Reply by ●October 13, 20122012-10-13
On Fri, 12 Oct 2012 09:29:55 -0700 (PDT), George Herold <gherold@teachspin.com> wrote:>On Oct 11, 4:36�pm, Tim Wescott <t...@seemywebsite.com> wrote: >> How commonly do you see PLL designs referred to as "type I", "type II", >> "type III", etc.? �Do the terms make sense to you? >> >> I'm writing a report; don't want to either baffle with bullshit nor leave >> out handy terms... >> >> -- >> My liberal friends think I'm a conservative kook. >> My conservative friends think I'm a liberal kook. >> Why am I not happy that they have found common ground? >> >> Tim Wescott, Communications, Control, Circuits & Softwarehttp://www.wescottdesign.com > >Nice thread, thanks Tim. > >I assume "Phaselock Techniques" by Flyod M. Gardener is the right >book. (Making my Xmas wish list.) Any advantage of the third edition >over the second? > >So in a type III system the error signal is integrated twice? >Does anyone have an example where double integration is used? >It doesn't have to be a PLL application any type of control loop would >be fine. > >George H.I am a fan of the D-flop bang-bang phase detector. It has, in theory, an infinite phase-error gain, which makes it interesting to analyze. That's the way to go if you want to lock an oscillator to an external input with picosecond long-term stability. -- John Larkin Highland Technology Inc www.highlandtechnology.com jlarkin at highlandtechnology dot com Precision electronic instrumentation Picosecond-resolution Digital Delay and Pulse generators Custom timing and laser controllers Photonics and fiberoptic TTL data links VME analog, thermocouple, LVDT, synchro, tachometer Multichannel arbitrary waveform generators
Reply by ●October 13, 20122012-10-13
On Fri, 12 Oct 2012 23:28:28 -0500, Tim Wescott <tim@seemywebsite.com> wrote:>On Sat, 13 Oct 2012 00:09:54 +0200, Jeroen wrote: > >> On 2012-10-12 19:05, Tim Wescott wrote: >>> On Fri, 12 Oct 2012 08:39:21 -0700, John Larkin wrote: >>> >>>> On Fri, 12 Oct 2012 10:39:14 -0400, Randy Yates >>>> <yates@digitalsignallabs.com> wrote: >>>> >>>>> Tim Wescott <tim@seemywebsite.com> writes: >>>>> >>>>>> How commonly do you see PLL designs referred to as "type I", "type >>>>>> II", "type III", etc.? Do the terms make sense to you? >>>>>> >>>>>> I'm writing a report; don't want to either baffle with bullshit nor >>>>>> leave out handy terms... >>>>> >>>>> Hi Tim, >>>>> >>>>> We used to use those terms in the 80s in our antenna control systems >>>>> at GTE Government Systems. If I remember correctly, the "number" >>>>> refers to the number of integrators in the loop. >>>>> >>>>> I don't think they are used much today. >>>> >>>> The question then becomes whether you count the inherent VCO phase >>>> integration as one of those integrators. >>> >>> For any control loop you pick a point in the loop and go around, >>> counting integrators, until you get back to the same point. Because >>> the VCO takes a voltage and turns it into a frequency (which is the >>> integral of phase), >> >> Harumph! Flub, phase is the integral of frequency. But you know that, of >> course. > >Blargh. Indeedie. >I get that backwards all the time, too. I don't know why. Eric Jacobsen Anchor Hill Communications www.anchorhill.com
Reply by ●October 13, 20122012-10-13
On Fri, 12 Oct 2012 09:29:55 -0700 (PDT), George Herold <gherold@teachspin.com> wrote:>So in a type III system the error signal is integrated twice? >Does anyone have an example where double integration is used? >It doesn't have to be a PLL application any type of control loop would >be fine.Different loop types exhibit different error characteristics. A Type-0 loop (no integrator) has position error. A Type-1 loop has no position error. A Type-2 loop has no position or velocity error. A Type-3 loop has no position, velocity, or acceleration error. The references to error here refer to steady-state conditions.
