[asac] DSB vs SSB option

[Roy Booth]

Dear Stephane,

I haven't had time to digest your document fully and I have an urgent 
meeting which will prevent my participation this afternoon.
However, you don't seem to have considered side-band separation mixers 
which give the advantages of SSB for line work and DSB for continuum if 
both sidebands are used.

Any comments?

I note the points about cost!

Regards,

Roy

At 14:38 2001-05-16 +0200, Stephane Guilloteau wrote:
>Please, look at the following document on DSB vs SSB
>
>http://iraux2.iram.fr/~guillote/alma/dsb-ssb-guilloteau.ps
>
>It differs from T.Hasegawa document because I consider that in continuum
>mode
>(or in multiple spectral line mode with spectral lines coming from opposite
>sidebands)
>DSB receivers can recover an extra sqrt(2) sensitivity factor because you
>effectively collect
>twice the bandwidth. This of course is a possible gain which can be factored
>out only if
>the effective fraction of projects requiring such a mode is known.
>
>The agreed upon value for bandwidth, 4 or 8 GHz, is still a matter of
>debate, essentially because we do not have sufficiently well proven design
>for 8 GHz bandwidths, while we have proven designs for 4 GHz.
>
>However, I agree with Tetsuo on the fact that the issue is too complicated
>for the time being, and should be deferred to another teleconf given the
>other agenda items.
>
>     Stephane



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