Thread: Disadvantages of using AM for DSSS/FHSS Spread Spectrum?
View Single Post
  #10   Report Post  
Old May 2nd 08, 06:44 PM posted to rec.radio.amateur.antenna
Cecil Moore[_2_] Cecil Moore[_2_] is offline
external usenet poster
  
First recorded activity by RadioBanter: Mar 2007
Posts: 3,521
Default Disadvantages of using AM for DSSS/FHSS Spread Spectrum?
Richard Harrison wrote:
FM usually occupies about twice the bandwidth of AM.

Thanks for adding "usually" to your original statement.
I was just pointing out that if the FM peak deviation
is equal to the maximum modulation frequency, then the
FM signal occupies the same bandwidth as AM. The S/N
ratio advantage usually enjoyed by FM over AM occurs
when the FM peak deviation is *greater than* the maximum
modulation frequency. FM seems to have been the original
"spread spectrum" mode. :-)
--
73, Cecil http://www.w5dxp.com
Reply With QuoteReply With Quote