--
CL -- I doubt, therefore I might be !






wrote in message
...
On Thu, 6 Oct 2005 07:21:02 -0700, "Caveat Lector"
wrote:



"Doug Smith W9WI" wrote in message
...
Caveat Lector wrote:
Every day in the USA you can hear stations broadcasting using double
sideband - suppressed carrier -- what are these/

FM broadcast stations -- but only if you're listening in stereo.

(the L-R channel is broadcast DSBSC on a 38KHz subcarrier on the main FM
signal)

(the same stereo method is, to my knowledge, used worldwide)
--
Doug Smith W9WI
Pleasant View (Nashville), TN EM66
http://www.w9wi.com

Very good Doug
Don't know if the scheme is used world wide - good question
Maybe others can confirm

As a second quiz -- what other information is transmitted besides the
main
R+L, 38 kHz DSBSC, and 19 kHz pilot carrier ?


Didn't it once include a subcarrier to allow the use of
elevator/background music for equipment rented by subscibers to the
service?

How about the kind of info displayed on digital receivers for
stuff like station id, station type and the like?

Yep some stations transmit in the subcarrier set such
things as digital or analog SCA (Subsidiary Communications Authorizations)
or RDS signals. these are carried in most cases on 76 and 92 KHz
subcarriers, although there is no steadfast rule for use of subcarrier
frequencies, only convention.

SCA at URL:
http://www.blackcatsystems.com/radio/sca.html

RDS at URL:
http://electronics.howstuffworks.com/question323.htm

CL