90 degree phase shifter

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

--
|  James E.Thompson, P.E.                           |    mens     |
|  Analog Innovations, Inc.                         |     et      |
|  Analog/Mixed-Signal ASIC\'s and Discrete Systems  |    manus    |
|  Phoenix, Arizona            Voice:(480)460-2350  |             |
|  E-mail Address at Website     Fax:(480)460-2142  |  Brass Rat  |
|       http://www.analog-innovations.com           |    1962     |
             
I love to cook with wine.      Sometimes I even put it in the food.

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

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

What are your REAL requirements?

Jim

Agreed - quadrature generation is the way to go. There are chips from Analog Devices

that do Direct Digital Synthesis complete with DACs. A quick scan of the descriptions came up with one quadrature device:

but there may be more.

- John_H

[snip]

Imaginary DC ?:-)

...Jim Thompson

-- | James E.Thompson, P.E. | mens | | Analog Innovations, Inc. | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | Phoenix, Arizona Voice:(480)460-2350 | | | E-mail Address at Website Fax:(480)460-2142 | Brass Rat | |

| 1962 | I love to cook with wine. Sometimes I even put it in the food.

--- 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 Professional Circuit Designer

--- 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 | +-------+

-- John Fields Professional Circuit Designer

"jp" schreef in bericht news: snipped-for-privacy@v46g2000cwv.googlegroups.com...

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.

--
Thanks, Frank.
(remove \'q\' and \'.invalid\' when replying by email)

"Jim Thompson" a écrit dans le message de news: snipped-for-privacy@4ax.com...

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.

--
Thanks,
Fred.

Fairly simple. Use a digital sinewave chip, and use the 90 degree shifted output pin... 8-)

Charlie

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

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

Jim

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

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

Cheers! Rich

Naaah! It was in 1593 ;-)

...Jim Thompson

-- | James E.Thompson, P.E. | mens | | Analog Innovations, Inc. | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | Phoenix, Arizona Voice:(480)460-2350 | | | E-mail Address at Website Fax:(480)460-2142 | Brass Rat | |

| 1962 | I love to cook with wine. Sometimes I even put it in the food.

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

--=20 Keith

"jp" a écrit dans le message de news: snipped-for-privacy@v46g2000cwv.googlegroups.com...

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.

--
Thanks,
Fred.

So, what did you do to celebrate it then?

--
Paul Hovnanian     mailto:Paul@Hovnanian.com
------------------------------------------------------------------
Telemark:  If it was easy, they\'d call it snowboarding.

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

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

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