Fwd: Re: [digitalradio] A closer look at ROS]]
Tom Azlin N4ZPT
n4zpt at cox.net
Mon Feb 22 10:31:36 CST 2010
That is similar to my question. What does the FCC define as spread
spectrum. AMRAD members who were part of the original request for SS
approval might know this.
Spreading is adding known redundancy otherwise you would not get
spreading gain. Using FEC is adding known redundance. 30 bps data
channel encoded to 300 baud using Multitone FSK then sounds the same.
So is this a big hoopla over nothing? Thus my question to the AMRAD
73, Tom n4zpt
On 2/22/2010 7:29 AM, Mike O'Dell wrote:
> so where in the regs is the definition of "bandwidth-expansion
> modulation" ??? that would seem to be the crux of this. it's
> also damn tricky.
> if one wishes to be extremely pedantic, which I don't recommend,
> *any* modulation of a raw carrier is an example of "bandwidth-expansion
> modulation". there is no other way to modulate - any impression of
> modulation on a carrier results in a wider signal, and this includes CW.
> It simply follows from Shannon - no increase in bandwidth,
> no information added.
> so pursuing that argument results in *all* HF operations being illegal.
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