Lucent Technologies Introduces
System-On-A-Chip Echo Canceler With
Tenfold Performance Improvement
Chip Targets Voice-Over-Internet-Protocol (VoIP) and POTS Applications
ALLENTOWN, Pa., April 20 /PRNewswire/ -- Lucent Technologies' (NYSE: LU - news)
Microelectronics Group today announced the first four-channel programmable communications
semiconductor chip, combining echo cancellation and coding/decoding (codec) functions, that
provides a ten decibel improvement in telephone line echo return loss performance compared to
traditional echo cancellation methods. The system-on-a-chip solution, called the T8533, has the
potential to substantially reduce total system costs compared to traditional network echo
cancelers, while providing great flexibility and convenience.
Echo cancelers eliminate the annoying echo caused by network delays and by impedance
mismatches at the ''hybrid,'' the location where telephone lines connect to a digital voice
network.
Lucent's integrated chip is the industry's first to comply with the International
Telecommunications Union G.168 and G.712 standards for echo cancellation and codec
technologies. The chip can be located on the telephone subscriber's premises; at the gateway to
an Internet Services Provider's (ISP) Voice-over-Internet Protocol (VoIP) network; or at the
point in a local exchange carrier's network where voice traffic is digitized or packetized.
Newer entrants, such as competitive local exchange carriers, may prefer to put echo cancellation
closest to the point where voice traffic enters their networks: a digital loop carrier system or a
telephone central office. This approach improves echo cancellation performance and can cost
less, depending on configuration, than the typical $60 per line for network-based echo
cancellation equipment. And the Lucent chip also has the potential to improve modem connection
speeds.
ISPs that want to provide voice capability, and other carriers implementing VoIP technology,
must add echo cancellation where voice traffic is packetized for transport over the network -- at
a modem, set-top or cable box, or network gateway.
''Designers of packetized voice networks can use the T8533 to eliminate echo before signal
processing begins, while automatically adapting to all impedance conditions encountered on
customers' lines,'' said Randy Pitts, an analog line card product manager with Lucent's
Microelectronics Group. ''And by integrating the echo cancellation function on the codec chip,
the T8533 allows designers to use their digital signal processors for other functions, avoiding
the need to develop or license the software to perform echo cancellation separately.''
Network designers can easily place this echo canceler chip at the location closest to where the
echo is generated, providing superior echo cancellation performance.
The chip, which implements codec and 64-tap echo cancellation functions for four telephone
lines, provides programmable control of key performance parameters, including gain, hybrid
balance, termination impedance, equalization, and echo cancellation. The chip automatically
turns off echo cancellation on a modem call and provides residual echo control and noise
modulation. The codec is globally applicable, producing Mu-law and A-law companded output,
or a 16-bit linear digital output for direct interface with digital signal processor chips. The
analog interface mates seamlessly with Lucent subscriber line interface circuit (SLIC)
architectures, minimizing the need for external components.
The T8533 comes in a 44-pin plastic leaded chip carrier (PLCC). The T8534, a companion
circuit that has data latches to control SLICs and other line card components, is housed in 68-pin
PLCC and 64-pin thin quad flat pack (TQFP) packages. Samples and production quantities of
both chips will be available in July 1999 and will be priced from $9.16 ($2.29 per channel) for
the T8533 to $10.44 ($2.61/channel) for the T8534. Prices for both devices are in quantities of
1,000.
For additional product information, customers in the U.S. may call the Lucent Technologies
Microelectronics Group Customer Response Center at 800-372-2447, Dept. R98. In Canada,
call 800-553-2448, Dept. R98. International customers should fax their request to
610-712-4106, or write to Lucent Technologies, Room 30L-15P-BA, 555 Union Boulevard,
Allentown, Pa. 18103.
Lucent Technologies designs, builds and delivers a wide range of public and private networks,
communications systems and software, data networking systems, business telephone systems and
microelectronics components. Bell Laboratories is the research and development arm for the
company. For more information on Lucent Technologies, headquartered in Murray Hill, N.J.,
USA, visit its web site at lucent.com.
Lucent's Microelectronics Group designs and manufactures integrated circuits and optoelectronic
components for the computer and communications industries. More information about the
Microelectronics Group is available from its web site at lucent.com.
SOURCE: Lucent Technologies |
