90 degree phase shifter

[jp]

Hi,

Does anyone have any suggestions on phase shifting a sinwave by 90
dgerees. I need to sweep a sinwave from 0 to 500kHz and phase shift it
by 90 degrees. Any suggestiions would be appreciated.

Thanks,
jp

 

[Jim Thompson]

Hi,

Does anyone have any suggestions on phase shifting a sinwave by 90
dgerees. I need to sweep a sinwave from 0 to 500kHz and phase shift it
by 90 degrees. Any suggestiions would be appreciated.

Thanks,
jp

It is difficult to do a passive 90° phase shift filter over more than
about an octave.

What are you trying to accomplish?

You might be better off using a quadrature square wave generator
followed by a tracking filter.

...Jim Thompson

 

[Thomas Magma]

Hi,

Does anyone have any suggestions on phase shifting a sinwave by 90
dgerees. I need to sweep a sinwave from 0 to 500kHz and phase shift it
by 90 degrees. Any suggestiions would be appreciated.

Thanks,
jp

Most PCI arbitrary waveform generators should be able to do this. There are
a lot of manufactures of them with all kinds of price ranges and
functionalities, so you really have to do your homework. Good luck.

Thomas

 

[RST Engineering \(jw\)]

Tell me, just because I'm nosy, how do you phase shift DC? (0 Hz.)

What are your REAL requirements?

Jim

 

[John_H]

It is difficult to do a passive 90° phase shift filter over more than
about an octave.

What are you trying to accomplish?

You might be better off using a quadrature square wave generator
followed by a tracking filter.

<snip signature>

Agreed - quadrature generation is the way to go. There are chips from
Analog Devices (www.analog.com) that do Direct Digital Synthesis complete
with DACs. A quick scan of the descriptions came up with one quadrature
device:

http://www.analog.com/en/prod/0,,AD9854,00.html

but there may be more.

- John_H

 

[Jim Thompson]

Tell me, just because I'm nosy, how do you phase shift DC? (0 Hz.)

What are your REAL requirements?

Jim

[snip]

Imaginary DC ?

...Jim Thompson

 

[John Fields]

Hi,

Does anyone have any suggestions on phase shifting a sinwave by 90
dgerees. I need to sweep a sinwave from 0 to 500kHz and phase shift it
by 90 degrees. Any suggestiions would be appreciated.

---
An easy, brute force way would be to count through a sine and a
cosine lookup table, output that data to a couple of DACs and LPF
the outputs to get rid of the jaggies. View in Courier:

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 |
+-------+

 

[John Fields]

Tell me, just because I'm nosy, how do you phase shift DC? (0 Hz.)

---
If you do it statically, once you define the rails and the
relationship between the two outputs, then that relationship will
exist all the way down to DC:


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 |
+-------+

 

[Frank Bemelman]

Hi,

Does anyone have any suggestions on phase shifting a sinwave by 90
dgerees. I need to sweep a sinwave from 0 to 500kHz and phase shift it
by 90 degrees. Any suggestiions would be appreciated.

Well, it's not that you take a sine wave and then sweep it.
You generate a sinewave, from 0-500Khz. Make your generator
so that it has 2 outputs, one shifted 90 degrees.

Sounds like a DDS job.

 

[Fred Bartoli]

Tell me, just because I'm nosy, how do you phase shift DC? (0 Hz.)

What are your REAL requirements?

Jim

[snip]

Imaginary DC ?

Nah. Have two fine wires, one for each signal and a temperature sensor.
When the first wire comes to 90 deg, then drive the other.

 

[Charlie Edmondson]

Hi,

Does anyone have any suggestions on phase shifting a sinwave by 90
dgerees. I need to sweep a sinwave from 0 to 500kHz and phase shift it
by 90 degrees. Any suggestiions would be appreciated.

Thanks,
jp

Fairly simple. Use a digital sinewave chip, and use the 90 degree
shifted output pin...

Charlie

 

[John Larkin]

Tell me, just because I'm nosy, how do you phase shift DC? (0 Hz.)

The sin() output stays zero, and the cos() stays +1. Forever.


Incidentally, yesterday. 3.14.2006, was Pi day, and we all missed it.

John

 

[RST Engineering \(jw\)]

Not true. In its honor I had boysenberry pi for dessert last night.

Jim

 

[AudioPhotonix]

I had Pizza Pi - along with 3.1416 pints of beer.

 

[Rich Grise]

It is difficult to do a passive 90° phase shift filter over more than
about an octave.

What are you trying to accomplish?

You might be better off using a quadrature square wave generator
followed by a tracking filter.

I'd like to see _anybody_ shift a 0 Hz sinewave by _any_ amount! ;-P

Cheers!
Rich

 

[Jim Thompson]

The sin() output stays zero, and the cos() stays +1. Forever.


Incidentally, yesterday. 3.14.2006, was Pi day, and we all missed it.

John

Naaah! It was in 1593 ;-)

...Jim Thompson

 

[Keith Williams]

I'd like to see _anybody_ shift a 0 Hz sinewave by _any_ amount! ;-P

How about shifting by 1V? Enough? ;-)

 

[Fred Bartoli]

Hi,

Does anyone have any suggestions on phase shifting a sinwave by 90
dgerees. I need to sweep a sinwave from 0 to 500kHz and phase shift it
by 90 degrees. Any suggestiions would be appreciated.

If the sinwave is something you don't have control over, which I doubt since
you want to sweep it, you can do this but the wide 0-500kHz range makes this
a bit more complex.

First you build a wide range 0-500kHz controled oscillator with a 2MHz
oscillator, a 2-2.5MHz VCO that you mix and LPF so as to obtain your
0-500kHz range.
Then you PLL that wide range oscillator to the incoming signal with a mixer
that'll give you the 90 deg shift.
The response time would be conditioned by how low in frequency you want to
go.

But the better way is as others said: build the quadrature into your
generator first IOW use a DDS.

 

[Paul Hovnanian P.E.]

Naaah! It was in 1593 ;-)

So, what did you do to celebrate it then?

 

[taff]

Not true. In its honor I had boysenberry pi for dessert last night.

Jim

Not in the UK, it falls on 31/4/2006

Taff.......
( Thunder Ridge PA, Bristol, UK )