David Robbins wrote:
>
> some of the low data rate digital methods used to communicate
> with nuclear missile submarines will out perform cw all the time.
> same with the methods used to retrieve data from planetary probes.
> there are also other ultra narrow bandwidth methods that will
> receive signals you could never hear.... and could never be done
> without digital receivers and decoders.
At last some one who is willing to bring digital correlation reccivers
and transmiters to amateur radio ... Although at each moment in time
these signals consist of very narrow band width signals the need to
frequency hop or shift to transmit data bits consumes a significant
amount of spectrum. .The higher th data rates thew more spectrum is
needed to transmit the data.
Cw still remains the narrowest single frequency
mode to transmit information reliably .. ( Human factors not taken into
account)... The other digital modes that we as amateurs use at present
remain spectrum hogs when compared to CW.
A light read that will give you some insight into these principals is
Modern Signals and Systems
By
Huibert Kwakernaak and Raphael Sivan
ISBN - 0-13-809252-4
Available at most University Book Stores.
73
de
ve6nap@oanet.com
--
FAQ on WWW: http://www.contesting.com/towertalkfaq.html
Submissions: towertalk@contesting.com
Administrative requests: towertalk-REQUEST@contesting.com
Problems: owner-towertalk@contesting.com
Search: http://www.contesting.com/km9p/search
|