Shaping radio today and tomorrow
Feb 1, 2003 12:00 PM, By Kari Taylor, associate editor
Do you remember?
PhilipsConsumer Electronics announced its first digital compact cassetteplayer and recorder in November 1992. The DCC900 was an extension ofthe compact cassette, and connected directly to a home stereo systemand came with a pre-recorded DCC music sampler. Two-channel audiosignals could be recorded with sampling frequencies of 48kHz, 44.1kHzand 32kHz. The dynamic range was better than 105dB, and the totalharmonic distortion, including noise, was less than 0.0025 percent.Recording time was as long as 90 minutes, with provision for 120minutes if a thinner tape was used.
The digital signals were recorded on nine parallel tracks, each 185micrometers wide with a track pitch of 195 micrometers. The height ofthe playback heads is 70 micrometers. This offered less sensitivity toazimuth errors than the analog compact cassette.
Two kinds of data could be recorded on the tape: main data in eighttracks and auxiliary data in one track. The format was intended toprovide digital recording to consumers in a format that resembledexisting analog compact cassettes. The format never caught on.
That was then
In theJanuary 1994 issue of Radio magazine we reported that USADigital was submitting two IBOC-FM DAB systems to the EIA/NRSC digitalradio tests, which were beginning that month. The second FM systememployed a significantly different implementation of IBOC technology.The receiver for the new system was based on silicon architecturerather than the gallium arsenide processor required by the previousformat's receiver.
The company demonstrated its first IBOC-FM system in various stagesof development at several national and regional trade events during1992 and 1993.
Sample and Hold
A look at the technology shaping radio
High speed lines connecting homes and business have increased
Source: FCC Study High Speed Services for Internet Access,
Status as of June 30, 2002