"Mario dei Pintarei" writes:

How does HD radio work? I'm an equipment designer (remote control
equipment) from Italy, we don't have it here. Never even heard about it! Is
it Digital? Modulation CODFM? what is the bandwith? Here in Italy we have
DAB... do you have that in the US?

We don't have DAB because the National Association of Broadcasters
lobbied against it several years ago when they realized it would give
all stations in a market essentially the same coverage and possibly
allow new competitors into the game.

They do have DAB in Canada, but we have IBOC ("in-band, on-channel"),
or "HD Radio" as it has been recently rebranded. HD Radio allows a
station on the AM or FM bands to transmit a digital signal along with
the conventional analog signal. The catch is that the maximum bit
rate permitted by HD Radio is 96 kbps on the FM band and about 36 kbps
on AM. By comparison, DAB allows up to 256 kbps.


umar