AMSS: Information and examples

here is an explanation given by James Briggs, originally posted on the Dream forum

details can be found in this ETSI document

Some examples of transmissions already using AMSS (decoder:Dream)

BBCWS 648 kHz from Orfordness

BBC WS on 9410 kHz from Limassol/Cyprus

RTL on 234 kHz from Beidweiler