# 90 degree phase shifter

Discussion in 'Electronic Design' started by jp, Mar 15, 2006.

1. ### Rich GriseGuest

Hm. According to this, there is no such tning. No wonder you Brits are
such squares. ;-P

Cheers!
Rich

2. ### Jim ThompsonGuest

pi are round, cakes are square ;-)

...Jim Thompson

3. ### Ken SmithGuest

Y = sin(0t)

Shifted version

Y = sin(0t + PI/2)

1V does sound like enough.

4. ### KeithGuest

He let 'em eat cake!

6. ### John_HGuest

Your response is nonsense, try again, there's already been a lot of help
from people who have a clue.

8. ### Guest

Lets see now, a 0hz sinewave? now lets try and phaseshift it.

9. ### John FieldsGuest

---
OK, here's the way I suggested:

COUNT SIN ROM SIN DAC
+------+ +-------+ +-------+
HFCK>--+--|> Qn|--+--------|An Dn|---|Dn OUT|--[R]--+-->SIN
| . . | . . . . |
| . . | . . . . [C]
| . . | . . . . |
| | Q0|--|-----+--|A0 D0|---|D0 | GND
| +------+ | | +-------+ |__ |
+------------|-----|-------------O|LE |
| | | +-------+
| | |
| | |
| | | COS ROM COS DAC
| | | +-------+ +-------+
| +-----|--|An Dn|---|Dn OUT|--[R]--+-->COS
| | . . . . |
| | . . . . [C]
| | . . . . |
| +--|A0 D0|---|DO | GND
| +-------+ |__ |
+--------------------------------O|LE |
+-------+

Note that if HFCK is stopped the frequency of SIN and COS will be
0Hz, but there will still be a 90° amplitude difference between
them.

10. ### Guest

This seems to come down to the problem of how you resolve a DC voltage
into its phase and magnitude.

If you know or can safely presume a representation of the form A sin (
Bt + c ) then you can easily phase shift it.

If you don't know, can't request more information, and can't get away
with making an arbitrary decision, then yes you have an undefined
problem.

11. ### Le Chaud LapinGuest

Mathematically speaking, it's perfectly acceptable. In fact, I would
be more worried about a model that treated 0 as a special case.

And since it is hard to describe a range whose lower bound is 0 without
using 0 as the lower bound...

-Le Chaud Lapin-

12. ### Rich GriseGuest

You may send your check to:
Richard Grise
c/o ABI Engineering
12143 Rivera Rd.
Whittier, CA 90606

Please pay to the order of Richard M. Grise.

Thanks!
;-)
Rich

13. ### Rich Grise, PLainclothes HippieGuest

Huh?

X >= 0 is a lot different from X > 0, in a lot of ways - ask any
programmer!

Cheers!
Rich
--
Elect Me President in 2008! I will:
A. Fire the IRS, and abolish the income tax
B. Legalize drugs
C. Stand down all military actions by the US that don't involve actual
military aggression against US territory
D. Declare World Peace I.

15. ### John LarkinGuest

With a big army, I assume.

John

16. ### Kalman RubinsonGuest

Declarations require little more than a piece of paper or a
microphone. Reality is something else.

Kal

17. ### Rich Grise, PLainclothes HippieGuest

That's kind of an oxymoron, as you know. As Commander-in-Chief of
all of the US Military, I would simply declare it unilaterally,

What's the only country on Earth that's currently engaged in aggression
against one or more foreign countries?

Thank you very much.

Cheers!
Rich
--
Elect Me President in 2008! I will:
A. Fire the IRS, and abolish the income tax
B. Legalize drugs
C. Stand down all military actions by the US that don't involve actual
military aggression against US territory
D. Declare World Peace I.

18. ### Rich Grise, PLainclothes HippieGuest

By making armies unnecessary.

Cheers!
Rich
--
Elect Me President in 2008! I will:
A. Fire the IRS, and abolish the income tax
B. Legalize drugs
C. Stand down all military actions by the US that don't involve actual
military aggression against US territory
D. Declare World Peace I.

19. ### Rich Grise, PLainclothes HippieGuest

And don't forget, this follows A, B, and C - get them done,
and nobody will feel like fighting. ;-)

Cheers!
Rich
--
Elect Me President in 2008! I will:
A. Fire the IRS, and abolish the income tax
B. Legalize drugs
C. Stand down all military actions by the US that don't involve actual
military aggression against US territory
D. Declare World Peace I.

20. ### John LarkinGuest

Your A, B, and C conditions were true for most of human history. And
human history is overwhelmingly the history of war.

John