28-03-2017, 10:50 AM
Thanks for that 1988 BBC link... Seems there are 2 types of so called 'floating carrier' systems: DAM that reduces the carrier power when low volume or no sound is transmitted, & AMD where the carrier is reduced when high volume sound is transmitted. To me they seem to work in opposite ways. Both are very clever ways of reducing the electric bill. It says that a disadvantage of DAM is that on weak signals when the modulation is low the reduced carrier power can increase noise a bit, would Mr/Mrs Average Listener notice though? Probably not. To me the AMD system seems very elegant as it uses the receiver AGC to make it work effectively, how it would sound on a crystal set or old TRF set without AGC I don't know...
