Circuit Contest - Last Day

I read in sci.electronics.design that Richard Kanarek wrote (in ) about 'Circuit Contest - Last Day', on Wed, 2 Nov 2005:

I believe it will actually be a giant swede and a convertible Yuan.

--
Regards, John Woodgate, OOO - Own Opinions Only.
If everything has been designed, a god designed evolution by natural selection.
http://www.jmwa.demon.co.uk Also see http://www.isce.org.uk

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Fearful Of Admitting Defeat.

We told you to cool it with those big capacitors.

--
 Thanks,
    - Win

Do you mean "swede" as in a person from Sweden, or do you mean (what we here call) a rutabaga or turnip.

Mark Zenier snipped-for-privacy@eskimo.com Googleproofaddress(account:mzenier provider:eskimo domain:com)

Fucking Old Abusive Drunk.

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?

Michael A. Terrell
Central Florida

4-channel sonar chip with 80dB of time variable gain (linear in dB), self-tuning gmC filters, and an I2C bus down the middle

...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.

Variable transconductance.

...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.

Not quite. Gilbert is a multiplier stack. This was done by simply changing the transconductance of a differential pair in a complicated fashion that varied signal handling capability inverse to gain.

At one point in time I posted the complex temperature tracking current reference that allowed ±0.5dB stability over the gain curve... one of my previous "what is it" postings ;-)

...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.

It's also noisy at low gains, figs 24, 25. Barry first attenuates the input signal then amplifies it back again.

--
 Thanks,
    - Win

In my sonar case the low-gain noise is not an issue... low gain equals high signal handling capability, so the SNR is still good.

...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.

I read in sci.electronics.design that Mark Zenier wrote (in ) about 'Circuit Contest - Last Day', on Wed, 2 Nov 2005:

I do so HATE having to explain. (;-)

Both; it's a PUN (check - Czech, Swede - swede). Geddit?

--
Regards, John Woodgate, OOO - Own Opinions Only.
If everything has been designed, a god designed evolution by natural selection.
http://www.jmwa.demon.co.uk Also see http://www.isce.org.uk

Hello Jim,

Does it work like the AD603 ladder or is it a stack of the usual Gilbert cells?

Only if you are at liberty to say, that is.

Regards, Joerg

Hello Jim,

IOW, Gilbert "de luxe" ;-)

Regards, Joerg

Hello Jim,

That is where chip solutions make life so much easier. Us discrete designers have to find cheap enough PIN diode pairs and generate a pilot carrier that allows tracking yet won't interfere with the passband signals. Or run the pilot straight through the amp. But as a reward we're gitten all the dynamic range we wants ;-)

The AD603 has an interesting attenuator up front that maintains good dynamic range. But that thang has become so expensive that I haven't used one in a design in years. They might still be under patent protection for that attenuator.

Regards, Joerg

Hello Win,

True. It was intended for ultrasound, or at least its forefather AD600 was. The main concern there is wall echoes of blood vessels which are huge at echoes nearby. A Gilbert multiplier just doesn't cut it for those jobs.

My favorite scheme is controlled resistance at the collector or drain, usually via PIN diode. But not 40dB worth of range in a single stage.

Regards, Joerg

Right, hence Barry's design decision. But I'd like to see an electronic attenuator with that architecture but with a say -20 to +20dB gain range.

--
 Thanks,
    - Win

I was just pedantically pointing out that a vanishingly small number of Americans would know about the root vegetable, as it's a parochial English usage.

I'm afraid I got it the first time. Uff Da. (Since we have more Swedish immigrants than Englishmen in my part of the country, implying they were "turnips", well ... ).

Mark Zenier snipped-for-privacy@eskimo.com Googleproofaddress(account:mzenier provider:eskimo domain:com)

Barry's cutest trick is the staggered sections of asymmetric differential (BJT) pairs... left device bigger than right paralleled with right bigger than left.

Analyse it sometime, you'll like it... I wish it wasn't patented ;-)

...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.

Hello Win,

The AD603 is -11dB to +31dB in its wide bandwidth configuration. It wouldn't be a big deal to migrate that into a chip that does -20dB to

+20dB. There may not be enough of a market for them to do it though.

Considering that I played with the AD600 around 1992 the patent may not have that much life left in it. But I doubt that there'll be much competition coming once it expires. It is such a small market and the really cost critical designs are likely going to remain discrete anyway.

Regards, Joerg