3 phase from func.gen. IC

On Mar 10, 6:17 pm, Bill Sloman <bill.slo...@ieee.org> wrote:
On Mar 10, 5:42 pm, John Larkin



jjlar...@highNOTlandTHIStechnologyPART.com> wrote:
On Wed, 10 Mar 2010 10:52:55 GMT, kevinl...@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
Given a single-phase sine wave as input, you could make an all-pass
network that would give two outputs that are 90 degree phase shifted
at all frequencies, then do some analog summing to make 120 and 240.
There are some allpass phase shifter circuits used in ham-radio type
SSB transmitters that aren't too horrible.
It could also be done with an integrator to make a 90 degree shift,
some sort of AGC to restore the amplitude, and some analog mixing.
And a few other terrible ways.
But it's probably easier to build a generator that inherently makes
quadrature or 3-phase sine waves.
Analog Devices do multi-output DDS chips that would probably do the
job.

A quick look suggests that a pair of synchronised AD9958 chips would
do the job

http://www.analog.com/en/rfif-components/direct-digital-synthesis-dds...

but a bit of trigometry with an AD9854 - which nominally generates
pairs of outputs in quadrature - might do the job for less money.

http://en.wikipedia.org/wiki/Trigonometric_functions

sin(x + y) = sin x. cos y + cos x.sin y

sin(2.pi.t + 3.pi/2) = sin(2.pi.t).cos(2.pi/3) + cos(2.pi.t).
sin(2.pi/3)

= sin(2.pi.t).-0.5 + cos(2.pi.t). 0.866025403

which you can get with a summing amplifier, as you can with sin(2.pi.t
+ 4.pi/3)

Once you've got two sine waves in quadrature, getting three phase is

On Wed, 10 Mar 2010 19:33:19 -0500 Jamie
jamie_ka1lpa_not_valid_after_ka1lpa__at_charter.net> wrote in Message id:
0AWln.78156$K81.64778_at_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?
Yes, of course

JW wrote:

On Wed, 10 Mar 2010 19:33:19 -0500 Jamie
jamie_ka1lpa_not_valid_after_ka1lpa__at_charter.net> wrote in Message id:
0AWln.78156$K81.64778_at_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.


I think you should be the last one, commenting on that.

On Mar 10, 5:42 pm, John Larkin



jjlar...@highNOTlandTHIStechnologyPART.com> wrote:
On Wed, 10 Mar 2010 10:52:55 GMT, kevinl...@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

Given a single-phase sine wave as input, you could make an all-pass
network that would give two outputs that are 90 degree phase shifted
at all frequencies, then do some analog summing to make 120 and 240.
There are some allpass phase shifter circuits used in ham-radio type
SSB transmitters that aren't too horrible.

It could also be done with an integrator to make a 90 degree shift,
some sort of AGC to restore the amplitude, and some analog mixing.

And a few other terrible ways.

But it's probably easier to build a generator that inherently makes
quadrature or 3-phase sine waves.

Analog Devices do multi-output DDS chips that would probably do the
job.

A quick look suggests that a pair of synchronised AD9958 chips would
do the job

http://www.analog.com/en/rfif-components/direct-digital-synthesis-dds...

but a bit of trigometry with an AD9854 - which nominally generates
pairs of outputs in quadrature - might do the job for less money.

Michael A. Terrell wrote:

JW wrote:

On Wed, 10 Mar 2010 19:33:19 -0500 Jamie
jamie_ka1lpa_not_valid_after_ka1lpa__at_charter.net> wrote in Message id:
0AWln.78156$K81.64778_at_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.


I think you should be the last one, commenting on that.

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
Learn to code a uC chip... A Pic, AVR, ATEML, ARm etc..
that has at least 3 ADC outputs..
The smaller family chips use a PWM (Pulse width modulator) that
can form a Sin wave on the output..

You code the math to generate the first base sine and then, offset
the other outputs at the proper angle.

Jamie wrote:

Michael A. Terrell wrote:


JW wrote:


On Wed, 10 Mar 2010 19:33:19 -0500 Jamie
jamie_ka1lpa_not_valid_after_ka1lpa__at_charter.net> wrote in Message id:
0AWln.78156$K81.64778_at_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.



I think you should be the last one, commenting on that.



When did you start thinking?


I've always been thinking. The mentally incapacitated, usually don't notice.

On Wed, 10 Mar 2010 19:33:19 -0500, Jamie
jamie_ka1lpa_not_valid_after_ka1lpa__at_charter.net> wrote:


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

Learn to code a uC chip... A Pic, AVR, ATEML, ARm etc..
that has at least 3 ADC outputs..
The smaller family chips use a PWM (Pulse width modulator) that
can form a Sin wave on the output..

You code the math to generate the first base sine and then, offset
the other outputs at the proper angle.


---
And how, exactly, would you do that over a 10:1 change in frequency?

JF

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?

Michael A. Terrell wrote:

Jamie wrote:

Michael A. Terrell wrote:


JW wrote:


On Wed, 10 Mar 2010 19:33:19 -0500 Jamie
jamie_ka1lpa_not_valid_after_ka1lpa__at_charter.net> wrote in Message id:
0AWln.78156$K81.64778_at_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.



I think you should be the last one, commenting on that.



When did you start thinking?


I've always been thinking. The mentally incapacitated, usually don't notice.

Don't fret, it'll probably take you a while to get this.

John Fields wrote:

On Wed, 10 Mar 2010 19:33:19 -0500, Jamie
jamie_ka1lpa_not_valid_after_ka1lpa__at_charter.net> wrote:


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

Learn to code a uC chip... A Pic, AVR, ATEML, ARm etc..
that has at least 3 ADC outputs..
The smaller family chips use a PWM (Pulse width modulator) that
can form a Sin wave on the output..

You code the math to generate the first base sine and then, offset
the other outputs at the proper angle.


---
And how, exactly, would you do that over a 10:1 change in frequency?

JF

Never made a variable frequency generator with a uC before?

it's very easy. Look at DDS technology. Just an old idea with a new
name on it and some alterations to make it possible for a wide range of
output.

With 20 Mhz uC's you can get 1khz sine waves via pwm with no problem
into a padded network that is unity buffered.

Even the slower ones can do that. Math isn't a problem, I just load a
data table with the integral coefficients to index into, for fast
computations of the PWM duty cycle.

And I have made a 3 phase 60 Hz reference generator with a PLL that
did a 12 cycle latency sample.

This was to replace an obsolete chip.
(via an older generation PIC). The output wave form looked clean....

btw, there are some external components needed to polish this off,
naturally. And if memory serves, I think microchip has newer uC's that
makes this even easier now.

Have a good day..

On Thu, 11 Mar 2010 21:03:15 -0500, Jamie
jamie_ka1lpa_not_valid_after_ka1lpa__at_charter.net> wrote:

John Fields wrote:

On Wed, 10 Mar 2010 19:33:19 -0500, Jamie
jamie_ka1lpa_not_valid_after_ka1lpa__at_charter.net> wrote:


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

Learn to code a uC chip... A Pic, AVR, ATEML, ARm etc..
that has at least 3 ADC outputs..
The smaller family chips use a PWM (Pulse width modulator) that
can form a Sin wave on the output..

You code the math to generate the first base sine and then, offset
the other outputs at the proper angle.


---
And how, exactly, would you do that over a 10:1 change in frequency?

JF

Never made a variable frequency generator with a uC before?

---
Heh...

One of the first ones I ever made was using the 6502 in a Commodore 64
and a light pen to translate the amplitude variations on the face of the
monitor into musical tones as the light pen was moved around the screen.
---

it's very easy. Look at DDS technology. Just an old idea with a new
name on it and some alterations to make it possible for a wide range of
output.

With 20 Mhz uC's you can get 1khz sine waves via pwm with no problem
into a padded network that is unity buffered.

---
20 _mega_ Hertz???

With an 8 bit counter, a lookup table, and a DAC, I can generate a
stand-alone 1000Hz sine wave using a 256kHz clock, and I can easily
change the frequency of the sine wave just by varying the clock
frequency, unlike you wastrels who demand ever-increasing µC clock
frequencies just to bring your monstrosities to life.
---

Even the slower ones can do that. Math isn't a problem, I just load a
data table with the integral coefficients to index into, for fast
computations of the PWM duty cycle.

---
Blah, blah, blah.
---

And I have made a 3 phase 60 Hz reference generator with a PLL that
did a 12 cycle latency sample.

---
BFD...

I can build a 3 phase 60Hz reference generator directly locked to a
crystal, with infinite latency and no need for a PLL, and so can just
about anybody else who's in this game.

YMMV.
---

This was to replace an obsolete chip.
(via an older generation PIC). The output wave form looked clean....

---
"Looking" clean isn't the same as "being" clean, and, since you've
admitted that you have a penchant for cheap-ass test equipment of
unknown accuracy, you're saying that a lick is as good as a promise.
---

btw, there are some external components needed to polish this off,
naturally. And if memory serves, I think microchip has newer uC's that
makes this even easier now.

---
More platitudes.
---

Have a good day..

---
Blow me.

JF

John Fields wrote:

On Wed, 10 Mar 2010 19:33:19 -0500, Jamie
jamie_ka1lpa_not_valid_after_ka1lpa__at_charter.net> wrote:


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

Learn to code a uC chip... A Pic, AVR, ATEML, ARm etc..
that has at least 3 ADC outputs..
The smaller family chips use a PWM (Pulse width modulator) that
can form a Sin wave on the output..

You code the math to generate the first base sine and then, offset
the other outputs at the proper angle.


---
And how, exactly, would you do that over a 10:1 change in frequency?

JF

Never made a variable frequency generator with a uC before?

it's very easy. Look at DDS technology. Just an old idea with a new
name on it and some alterations to make it possible for a wide range of
output.

With 20 Mhz uC's you can get 1khz sine waves via pwm with no problem
into a padded network that is unity buffered.

Even the slower ones can do that. Math isn't a problem, I just load a
data table with the integral coefficients to index into, for fast
computations of the PWM duty cycle.

John Fields wrote:
On Thu, 11 Mar 2010 21:03:15 -0500, Jamie
jamie_ka1lpa_not_valid_after_ka1lpa__at_charter.net> wrote:


John Fields wrote:


On Wed, 10 Mar 2010 19:33:19 -0500, Jamie
jamie_ka1lpa_not_valid_after_ka1lpa__at_charter.net> wrote:



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

Learn to code a uC chip... A Pic, AVR, ATEML, ARm etc..
that has at least 3 ADC outputs..
The smaller family chips use a PWM (Pulse width modulator) that
can form a Sin wave on the output..

You code the math to generate the first base sine and then, offset
the other outputs at the proper angle.


---
And how, exactly, would you do that over a 10:1 change in frequency?

JF

Never made a variable frequency generator with a uC before?


---
Heh...

One of the first ones I ever made was using the 6502 in a Commodore 64
and a light pen to translate the amplitude variations on the face of the
monitor into musical tones as the light pen was moved around the screen.
---


it's very easy. Look at DDS technology. Just an old idea with a new
name on it and some alterations to make it possible for a wide range of
output.

With 20 Mhz uC's you can get 1khz sine waves via pwm with no problem
into a padded network that is unity buffered.


---
20 _mega_ Hertz???

With an 8 bit counter, a lookup table, and a DAC, I can generate a
stand-alone 1000Hz sine wave using a 256kHz clock, and I can easily
change the frequency of the sine wave just by varying the clock
frequency, unlike you wastrels who demand ever-increasing µC clock
frequencies just to bring your monstrosities to life.
---


Even the slower ones can do that. Math isn't a problem, I just load a
data table with the integral coefficients to index into, for fast
computations of the PWM duty cycle.


---
Blah, blah, blah.
---


And I have made a 3 phase 60 Hz reference generator with a PLL that
did a 12 cycle latency sample.


---
BFD...

I can build a 3 phase 60Hz reference generator directly locked to a
crystal, with infinite latency and no need for a PLL, and so can just
about anybody else who's in this game.

YMMV.
---


This was to replace an obsolete chip.
(via an older generation PIC). The output wave form looked clean....


---
"Looking" clean isn't the same as "being" clean, and, since you've
admitted that you have a penchant for cheap-ass test equipment of
unknown accuracy, you're saying that a lick is as good as a promise.
---


btw, there are some external components needed to polish this off,
naturally. And if memory serves, I think microchip has newer uC's that
makes this even easier now.


---
More platitudes.
---


Have a good day..


---
Blow me.
Professional courtesy response, I presume ?

JF
My my, what vulgarity out of a prestige young man, like yourself.

20 _mega_ Hertz???

With an 8 bit counter, a lookup table, and a DAC, I can generate a
stand-alone 1000Hz sine wave using a 256kHz clock ...