Scientific-Atlanta Expands HD Head-End Offerings

The delivery of HD signals over cable TV systems just picked up a bit more steam with Scientific-Atlanta's announcement that it has two new HD demodulators targeted for cable applications. Since over-the-air broadcasts use 8VSB modulation for DTV and cable systems generally use 256QAM, cable head-ends require demodulators to provide the baseband ASI signal (19.4 Mbps), which is then remodulated as a 256QAM channel. Using this technology, cable systems can pack two HDTV channels onto a single 6 MHz cable channel.

The two new products are the D6238 demodulator and the more complex D6239 demodulator/multiplexer, with the latter containing the additional components necessary to stack two 256QAM channels onto a single cable channel. Both can receive an over-the-air broadcast from any local DTV broadcaster.

For more information, go to Scientific-Atlanta's Web site,