In Reply to: FM Future in the US? posted by Todd A. on December 12, 2014 at 14:31:55:
"HD" in the U.S. digital FM world does NOT mean "high-definition", although the industry doesn't seem to go out of their way to correct this misconception. HD stands for "Hybrid Digital", describing the scheme used to piggyback digitally-encoded programs within the assigned analog FM frequency bandwidth.
Audio quality from the HD signal is not necessarily superior to ordinary FM. It can be worse in some ways. Much depends on signal strength and other factors. Whereas analog FM quality (S/N) generally degrades gradually with range from the transmitter, usable range of the digital signal is less -- and it fails abruptly. Indeed, the HD receiver is designed to automatically fall back on the analog FM broadcast when the HD loses lock. That's why HD stations put several seconds delay in their analog program: this give the receiver time to decide whether to serve up the analog FM or the digital HD version.
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Follow Ups
- HD = Hybrid Digital - Charlie S in Maryland 14:38:57 12/18/14 (1)
- RE: HD = Hybrid Digital - Todd A. 15:05:15 12/18/14 (0)