Re: gEDA-user: Building the PCB+GL branch [WAS: Re: Open GL survey (for PCB)]

[Daniel Svärd <daniel.svard@xxxxxxxxx>]

     The one from which my remarks were derived came from googling and
     reading three or four pages which gave definitions, such as
     [1]http://en.wikipedia.org/wiki/Baseband and
     [2]http://en.wikipedia.org/wiki/Broadband.  It is that baseband
     uses the
     frequency range whose low-frequency end is at 0Hz; broadband avoids
     this, with its low-frequency cutoff well above that.  As the
     "Broadband" wikipedia page points out, the term can also refer to
     any
     signal whose bandwidth is wide compared to something else, but
     that's
     not a very useful definition in this context, as there is no
     obvious
     "something else" to compare to.
     Actually, channels sharing bandwidth can happen on baseband or
     broadband, via either TDM or FDM (though whether FDM is baseband
     depends on your point of view; an FDM-shared medium is not baseband
     for
     more than one of the signals making it up, though if you think of
     them
     as aggregated then the term may be fair).

   That is my view of the thing as well. The baseband signal is what is
   left when you down-convert your recieved signal from the RF-band
   (assuming it is up-converted at all at the transmitter. Some
   communication systems send at baseband.). So the baseband is basically
   what the computer (or whatever device) processes.
   And "broadband" feels just like a marketing word for me. The higher
   your carrier frequency, the wider your basband can be, increasing
   throughput.
   Daniel

References

   1. http://en.wikipedia.org/wiki/Baseband
   2. http://en.wikipedia.org/wiki/Broadband


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