gEDA-user: Barrie Gilbert

[Bob Paddock]

On Wednesday 06 September 2006 03:36, Karel Kulhavy wrote:
> Anyone knows what exactly is called Gilbert cell?

The Gilbert Cell is named after Barrie Gilbert of Analog Devices,
invented in 1968.

http://www.ieee.org/organizations/pubs/newsletters/sscs/jan03/jssc_classic.html

The Gilbert Cell has become common in RF designs, used as a double balanced
mixer.   It is a four quadrant multiplier.  Somewhere in my files I have a paper
by Gilbert  where he states that he never really meant it to be used the way,
that has been the most common usage.  He recommended an obscure
division technique instead.  I'll dig the paper up this evening.

> How many transistors does it actually have?

http://rfdesign.com/mag/503rfdf1.pdf

> Is it possible to make a well working Gilbert cell with ordinary non-matched
> transistors? 
> And btw do you know what translinear mean?

One set of frequencies is translated linearly to an other set of frequencies.
Using non-matched transistors will not be linear, resulting in spurious outputs.

What is it you really need to do?  If it is a simple AM demodulation you can
make a Synchronous Demodulator out of 4000 family gates.  There is also
a simple two transistor Synchronous Oscillator/Demodulator.  Look at the Application Note
section at http://www.unusualresearch.com/ .

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