Philips rolls second-generation DTV chip set
eetimes.com
By George Leopold
EE Times
(04/12/99, 11:34 a.m. EDT)
SUNNYVALE, Calif. — Several years of testing and deployment of
digital-TV services are yielding second-generation chip sets designed to
improve reception of digital broadcast signals. Philips Semiconductors, for
instance, today will unveil a two-chip front-end device designed to improve
indoor reception of DTV broadcast signals.
The hybrid analog and digital chip set includes an input processor and a DTV
demodulator/decoder. The product supports the Advanced Television
Systems Committee's vestigial sideband (VSB) demodulator standard as well
as NTSC channel decoding for analog sets.
Simon Wegerif, Philips Semiconductors' manager of product marketing and
business development, said the chip set provides more-rugged reception of
DTV broadcast signals by overcoming multipath signal interference. DTV
testing has turned up significant problems on that front, particularly in New
York and other large cities where the first digital broadcasts originated.
The digital front end improves reception, Wegerif said, by extracting the
synchronization pulse from a DTV signal. A "complex" equalizer then
reduces the worst effects of multipath interference. The result, said the
Philips executive, is more-reliable performance in second-generation DTV
receivers.
Reduces chip count
Philips also said its input processor is intended to reduce chip count,
eliminating many components by integrating NTSC decoding, an IF circuit,
picture and sound demodulation, and VSB down conversion into a single
device. The reduced chip count could cut DTV receiver manufacturers'
costs by 20 percent, Wegerif estimated.
Philips has been developing low-component-count reference designs aimed at
slashing today's high prices for DTV receivers. The chip maker is in talks
with "a lot of manufacturers" about design-ins of the chip set, Wegerif said,
but he declined to identify potential customers.
Yet the chip set also handles analog NTSC signals. "Since the transition to
DTV will not happen overnight, we recognize the need to continue handling
the analog signals found in homes today," Wegerif said. The NTSC
demodulator/decoder is also designed to cancel NTSC co-channel
interference.
Philips said the chip set supports parallel (8-bit) or serial MPEG-2
transport-stream output and includes an I2C-bus interface. It also supports
format conversion for analog devices such as VCRs as well as cable-TV and
set-top boxes. Backward compatibility is necessary to support potential input
devices favored by consumers, Philips said.
As digital-TV receiver costs slowly start to drop, greater attention could turn
to using the ATSC signal to relay data to users. "We're seeing more interest
in data-broadcast services," Wegerif said. Medium-scale trials of about 1,000
DTV receivers could start as early as this year. |
