Freq. Independent Phase Shifter
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From: Phil Allison on 11 May 2010 07:28 "Spehro Pefhany" "Phil Allison" >"Joke" > >>> >>> A Hilbert shifter works well, depends on the precision and how many >>> octaves you want. Also, you'd need to get hold of 0.5% or better film >>> capacitors which is not easy anymore these days. >> >> >>** The use of 0.5% tolerance caps implies a phase ripple or error of >>better >>than 1 degree max. >> >>Using 1% tolerance or 1% values selected from 5% stock, the max phase >>error >>is not more than 2 degrees. >> >>There is no problem designing a Hilbert phase shift network that covers >>from >>22 Hz to 20 kHz using only 10nF and 1nF polystyrene caps of nominal 1% >>tolerance, 1% MF resistors and a few FET op-amps. > > > 0.1% resistors are cheap these days. ** Still about 25 times the cost of 1% MF and of no benefit when the caps used are only 1% tolerance. > Where can you buy PS caps of any tolerance ? ** LCR Components make polystyrene caps of 1% tolerance & Farnell / Newark sell them - among others. http://www.newark.com/lcr-components/mkp-hr-10000pf-1/capacitor-10nf-63v-capacitor-10nf/dp/73K0558 $1.54 each in *one off* cheap enough for you - eh ??? > NPO ceramic parts are available, but $$$$. ** Really ??? 1% tolerance * silvered mica * caps are available in values like 10nF for big bucks. BTW: What the HELL is the point of your TEDIOUS BLOODY nit picking ???? Got nothing better to do with your life ?? ..... Phil
From: Spehro Pefhany on 11 May 2010 07:40 On Tue, 11 May 2010 21:28:50 +1000, the renowned "Phil Allison" <phil_a(a)tpg.com.au> wrote: > >"Spehro Pefhany" >"Phil Allison" >>"Joke" >> >>>> >>>> A Hilbert shifter works well, depends on the precision and how many >>>> octaves you want. Also, you'd need to get hold of 0.5% or better film >>>> capacitors which is not easy anymore these days. >>> >>> >>>** The use of 0.5% tolerance caps implies a phase ripple or error of >>>better >>>than 1 degree max. >>> >>>Using 1% tolerance or 1% values selected from 5% stock, the max phase >>>error >>>is not more than 2 degrees. >>> >>>There is no problem designing a Hilbert phase shift network that covers >>>from >>>22 Hz to 20 kHz using only 10nF and 1nF polystyrene caps of nominal 1% >>>tolerance, 1% MF resistors and a few FET op-amps. >> >> >> 0.1% resistors are cheap these days. > > >** Still about 25 times the cost of 1% MF and of no benefit when the caps >used are only 1% tolerance. Should improve things by about 30%. > >> Where can you buy PS caps of any tolerance ? > > >** LCR Components make polystyrene caps of 1% tolerance & Farnell / Newark >sell them - among others. > >http://www.newark.com/lcr-components/mkp-hr-10000pf-1/capacitor-10nf-63v-capacitor-10nf/dp/73K0558 > >$1.54 each in *one off* cheap enough for you - eh ??? Cheap enough. I've heard a lot of complaints about poor availability of PS caps and PP caps. > >> NPO ceramic parts are available, but $$$$. > > >** Really ??? Yeah, 18125A103FAT2A AVX 10nF 1% NPO in 1812 form factor, but about five clams a pop in tens. http://www.avx.com/docs/Catalogs/ccog.pdf >1% tolerance * silvered mica * caps are available in values like 10nF for >big bucks. > > >BTW: > >What the HELL is the point of your TEDIOUS BLOODY nit picking ???? > >Got nothing better to do with your life ?? Apparently, not at the moment, Phil. How about yourself? >.... Phil > Best regards, Spehro Pefhany -- "it's the network..." "The Journey is the reward" speff(a)interlog.com Info for manufacturers: http://www.trexon.com Embedded software/hardware/analog Info for designers: http://www.speff.com
From: Jan Panteltje on 11 May 2010 09:38 On a sunny day (Mon, 10 May 2010 13:57:33 -0700) it happened Joerg <invalid(a)invalid.invalid> wrote in <84raa0F148U1(a)mid.individual.net>: >Hint: One can load revolving wave tables into a sound card :-) You can also load Mozart's into it :-) Or 'All you need is love' from the Beatles :-)
From: George Herold on 11 May 2010 09:47 On May 11, 3:21 am, billmur...(a)protech.com (Bill Murphy) wrote: > On Mon, 10 May 2010 18:24:52 -0700 (PDT), MooseFET > > <kensm...(a)rahul.net> wrote: > >What are the two other channels making? > > Same signal, all spearated by 120 degrees. Done in CoolEdit. > > >If you have two signals at 90 degrees, you can get any other phase > >and the same amplitude. > > Can you give me a hint how, or where to find out please? > > Bill Murphy The simple way is to mix them in a pot. (NPI) (View in Couriers) Sine----+ | P O<----output T | Cosine--+ But this has an amplitude variation as you move the pot wiper around, perhaps MooseFET knows a trick to eliminate the amplitude change. George H.
From: MooseFET on 11 May 2010 09:49
On May 11, 12:21 am, billmur...(a)protech.com (Bill Murphy) wrote: > On Mon, 10 May 2010 18:24:52 -0700 (PDT), MooseFET > > <kensm...(a)rahul.net> wrote: > >What are the two other channels making? > > Same signal, all spearated by 120 degrees. Done in CoolEdit. > > >If you have two signals at 90 degrees, you can get any other phase > >and the same amplitude. > > Can you give me a hint how, or where to find out please? > > Bill Murphy Read Phil's reply ASCII art sin(t)----+--------- ! ! ! \ \ / R1 / \ \ ! /<--------+ \ +----------+----/\/\------ / ! ! ! \ / ! ! / \ --!+\ ! \ / ! >--+-----+---- Out ! ! --!-/ ! sin(t+a)--+--------- ! ! +--/\/\-- ! \ / \ ! GND If you make the phase angle "a" 100 degrees, you can make R1 a 10 turn pot with a counter knob that sets the phase angle in degrees. With the right values for all the resistors, the gain is nearly constant and the phases nearly spot on. |