Re: gEDA-user: Barrie Gilbert

[Karel Kulhavy <clock@xxxxxxxxxxxxx>]

On Wed, Sep 06, 2006 at 06:09:10AM -0400, Bob Paddock wrote:
> 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

I thought I have Gilbert cells in my Ronja RX, but that was because someone
somewhere incorrectly called a long-tail pair Gilbert cell. So I was wondering
what is the actual Gilbert cell.

CL<

> 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/ .
> 
> -- 
>  http://www.softwaresafety.net/ http://www.designer-iii.com/
>                  
> 
> 
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