On Tue, 24 Mar 2009 16:08:46 -0700, "Joel Koltner"
wrote:

Still, AFAIK all that averaging can do is to effectively lower the noise floor
at the expense of bandwidth (effectively data rate), and the more benefit
you'd like to get from that averaging, the more important your sample points
become, which gets back to needing as little phase noise as possible on your
oscillators. Is there some other angle here?

That was a curious objection to a solution answering a problem as it
was specifically stated. Are there angles to showing noise being
overcome by several means when you offered none?

noise is the primary factor that limits how far
you can transmit a signal and still recovery it successfully.

Again, "qualified" statements such as that should be able to support
themselves with quantifiables.

What "noise" were you speaking about when through the course of this
thread it has most often been confined to kTB than, say, cross-talk,
splatter, spurs, whistlers, howlers, jamming, and a host of others?

What constitutes "successfully?" Is this a personal sense of well
being, or is it supported by a metric?

What constitutes "far"ness? At one point you offered from hilltop to
hilltop with antennas combining to 60dB directivity (but curiously
expressed as SNR). Lacking any quantifiable of what size hills,
shouting can be competitive at some range, and reasonably assured of
being understood to the first order of approximation without need for
averaging.

Spread Spectrum is so ubiquitous that waiting on anticipated exotic
failures of phase noise, on the face of an overwhelming absence of
problems, is wasted time indeed. Communication problems via the Cell
technology are more likely packets going astray on the network than
through the air. Perhaps it is with the clock chips of network
routers where phase noise fulfill this perception of sampling error -
but even there, collision is more likely and the system merely
abandons retries for the sake of economy not for overwhelming noise.

As to sampling error via the net. Time was when 16x over-sampling for
RS-232 was the norm. Going to one sample and transmitting at the base
frequency didn't help until quadrature and more complex phase systems
emerged. Same infrastructure, same noise, faster and more efficient
(not less) communication. Shannon wrote about the bit error rate in
the presence of noise, modulation techniques have improved throughput,
not lowered it.

73's
Richard Clark, KB7QHC