3 phase from func.gen. IC
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From: Robert Baer on 11 Mar 2010 00:58 Kevin Lang wrote: > What would be the simplest way to derive a simultaneous three phase > output from a sine wave produced by a single function generator IC ... > that does not change as the frequency is varied? > > Specifically, two additional sinewaves remaining 120 and 240 degrees > out of phase with the original as the frequency is varied between > 100Hz and 1KHz. > > Kevin Lang Refer to analog computers and work done then (40 or so years ago well before "solid state"). Even the x=-x.. generator needs tuning for sine generation, so what is wrong with using three phase retard stages with "ganged" tuning to maintain fixed phase delay on each stage?
From: Robert Baer on 11 Mar 2010 01:01 dcaster(a)krl.org wrote: > On Mar 10, 10:52 am, kevinl...(a)hartley.com (Kevin Lang) wrote: >> What would be the simplest way to derive a simultaneous three phase >> output from a sine wave produced by a single function generator IC ... >> that does not change as the frequency is varied? >> >> Specifically, two additional sinewaves remaining 120 and 240 degrees >> out of phase with the original as the frequency is varied between >> 100Hz and 1KHz. >> >> Kevin Lang > > I would look at Microchip's application notes. I think they have a > PIC that is used for variable frequency drives. Does the whole > thing. The function generator with three phase output. Might not be > what you want as the sinewave would not be a real sine wave. It would > be a pulse width modulated output. > > > Dan DIY; use a look-up table containing a DAC representation of a sine wave and have the program "pick off" (pun NOT intended) the phases for output to 3 DACs.
From: Robert Baer on 11 Mar 2010 01:02 John Fields wrote: > On Wed, 10 Mar 2010 10:52:55 GMT, kevinlang(a)hartley.com (Kevin Lang) > wrote: > >> What would be the simplest way to derive a simultaneous three phase >> output from a sine wave produced by a single function generator IC ... >> that does not change as the frequency is varied? >> >> Specifically, two additional sinewaves remaining 120 and 240 degrees >> out of phase with the original as the frequency is varied between >> 100Hz and 1KHz. > > --- > View in Courier: > > > CLK>-+--[COUNT]-+-[LUT000]--[DAC]--[LPF]--> > | > | > +-[LUT120]--[DAC]--[LPF]--> > | > | > +-[LUT240]--[DAC]--[LPF]--> > > > JF If i played a fLUTe,would that do?
From: JW on 11 Mar 2010 05:27 On Wed, 10 Mar 2010 19:33:19 -0500 Jamie <jamie_ka1lpa_not_valid_after_ka1lpa_(a)charter.net> wrote in Message id: <0AWln.78156$K81.64778(a)newsfe18.iad>: > Learn to code a uC chip... A Pic, AVR, ATEML, ARm etc.. >that has at least 3 ADC outputs.. ADC outputs? Do you mean DAC?
From: Michael A. Terrell on 11 Mar 2010 10:43
JW wrote: > > On Wed, 10 Mar 2010 19:33:19 -0500 Jamie > <jamie_ka1lpa_not_valid_after_ka1lpa_(a)charter.net> wrote in Message id: > <0AWln.78156$K81.64778(a)newsfe18.iad>: > > > Learn to code a uC chip... A Pic, AVR, ATEML, ARm etc.. > >that has at least 3 ADC outputs.. > > ADC outputs? Do you mean DAC? He never knows what he means. -- Greed is the root of all eBay. |