Speaking of bandwidth:
A separate document, so far called “NRSC-G100,” illustrates “the relationship of transmitted analog AM bandwidth with interference considerations as related to receiver test results,” Salek said.
Remember that awhile back, we reported that NPR Labs was characterizing 30 or so receivers, on the bench and in the field; that research was for the NRSC. The tests were to determine how much of the bandwidth they recover from an AM transmitted signal.
“Mainstream receivers never did go out as wide as the 10 kHz NRSC standard,” said Salek. The idea is, why not better match up the transmitted signal with what the radio can receive?
Discussion in the document describes how to narrow the transmitted analog or digital bandwidth. The general recommendation is 7 kHz, he said.
When Clear Channel narrowed the transmitted bandwidth on its AMs to some 5 kHz about two years ago (a story that RW broke), the concept was controversial. That’s why this discussion is not part of the standard but placed in a separate document.
Clear Channel Radio’s Jeff Littlejohn, who led the Clear Channel narrowing move, co-chairs the subcommittee, which will exist until at least CES. After that, the roughly 15-member group may go on hiatus until needed again.