<<On Wed, 27 Jan 2021 15:02:30 -0800, Paul Eggert <eggert@cs.ucla.edu> said:
And as far as I know, KNX's audio time signal is no more accurate now than it was in the 1990s.
Most CBS owned-and-operated radio stations installed "HD Radio", which requires an eight-second delay in the analog audio to match the compression delays on the digital side. (CBS Radio's then national VP of engineering, Glynn Walden, was heavily involved in the creation and promotion of the "HD Radio" system.) Receivers may add additional decoding delays so long as they delay analog audio an equal amount. (This allows for "seamless" cross-fading between the analog and digital signals at the fringes of the digital coverage area.) The encoding delay for "HD2" and other low-bandwidth subchannels is even longer, about 30 seconds (there's no blend-to-analog issue there, just the encoder). Even before HD Radio, CBS affiliates that carried the network news at the top of the hour would normally take the "bong" from the network feed, via satellite. However, CBS stations running a talk format would not normally dump the profanity delay for the news, so the network "bong" would be delayed another seven to fifteen seconds. Some talk stations chose to insert their own top-hour tone after the profanity delay, often at the transmitter. (Aside: When Westinghouse bought CBS, this combined Westinghouse's all-news stations with CBS's all-news stations in several major markets, including Los Angeles; other than New York, the weaker of the two stations ended up changing formats. But after Westinghouse changed its corporate name to "CBS", this had the effect that "CBS" owned a number of radio stations that were not affiliates of the CBS Radio Network -- the former Group W stations were primarily ABC Information Network affiliates if they had any network at all. ABC-I didn't broadcast a top-hour time signal, so those stations, like WBZ in Boston, already had their own local top-hour beeps if they wanted. WTIC in Hartford, which wasn't a Westinghouse station but did later become part of CBS Radio, famously kept its V-for-Victory Morse code interval signal from World War II. A few years back, CBS spun off its radio unit to Entercom, but kept the CBS Radio News network under the new name "CBS News Radio".) -GAWollman