Re: [Phys-l] WIFI

[Bernard Cleyet <bernardcleyet@redshift.com>]

On 2012, Apr 08, , at 17:59, John Denker wrote:

> Returning to the communications example:  Starting from 256-QAM,
> if you throw away the v2 axis in phase space, and collapse
> everything down onto the v1 axis, you would be throwing away
> something like 15/16ths of the available phase space.  Not a
> good idea.


Do these communications suppress the carrier (unnecessary as a local oscillator is used?)


bc knows SSSC requires a crystal controlled exciter (BFO?).  Or perhaps a lock-in receiver?



p.s.


On 2012, Apr 08, , at 17:59, John Denker wrote:

> This is a fairly good shibboleth for identifying experimental 
> physicists:  If you ask somebody to measure an AC signal, the 
> physicist will instinctively reach for a lockin amplifier, in 
> situations where an ordinary mortal would reach for a voltmeter.


A 'scope is just a voltmeter?


p.p.s   not quite the subject, but I found interesting:

When I was setting up the scattering experiment [ MPT looking (at various angles) at a phial of micron sized spheres in water-alcohol illuminated by a He-Ne LASER], I found it easier to connect the output of the variable band pass amplifier to a speaker in addition to the FFT spectrum analyzer.


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