ZL38065 Product Preview

32-CHANNEL
VOICE ECHO CANCELLER ZL38065
PRODUCT PREVIEW
The ZL™38065 is a highly integrated VEC (voice echo canceller) that optimizes
call quality in a wide range of low-density wireless and telephony equipment.
The off-the-shelf device supports 32 voice channels, and cancels echo tails of
64 milliseconds or 128 ms.
The VEC chip utilizes a patented NLP (non-linear processing) technology that
outperforms competing devices in the presence of intense background noises.
These features help ensure carrier-grade voice connections and improve subjective voice quality by removing echoes, clicks, and hisses caused by the user
environment, network conditions and round-trip delays in speech signals.
The device uses an efficient architecture that reduces board space and development resource requirements.
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Fast re-convergence on echo path
changes
Fully programmable convergence
speeds per-channel improves
performance during double-talk
Flexibility and Ease-of-Use
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Each ECG offers parallel DSP
processing without resource
sharing limitations
Compatible pin-outs simplify
system upgrades
Standards Compliant
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Configurable to allow simultaneous
operation of dual channel ECG
(echo canceller group) at 64 ms, bidirectional 64 ms or 128 ms
Low-power operation (4.6 mW per
channel) with independent powerdown mode
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Full band convergence allows
multiple echo reflection cancellation
Protection against narrowband
signal divergence in high echo
environments or in the presence of
DTMF or other tones
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NLP with adaptive suppression
threshold and spectrally matched
comfort noise injection removes
residual echo and minimizes
switching effects
Adjustable signal gain/loss
improves ERL performance and
flexibility for system gains
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Highest Voice Quality with Advanced
Noise Matching
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ITU-T G.168 (2000), G.168 (2002)
and ITU-T G.165
Fax/modem G.164 2100 Hz Tone
Disable
Streamlines AT&T equipment
certifications
Applications
Wireless local loop base stations &
controllers (PHS/DECT)
Voice/telephony gateways and
digital PBX systems
Integrated access devices
Packaging and Availability
100-pin LQFP or 208-ball LBGA
In volume production
Customer Support
The ZL38065 VEC is supported by
Zarlink’s network of in-house field
application and design engineers.
Evaluation boards with full design
and applications documentation are
available.
32-CHANNEL
ZL38065 VOICE ECHO CANCELLER
APPLICATION
IP-PBX
The ZL38065 VEC improves voice quality in low-density networking equipment, such IP-PBXs, where the convergence
of voice and data traffic on a packet network causes processing delays that emphasize echo. In addition, excessive
background noise introduced when equipment is operating
in a high-noise environment, such as an industrial setting or
airport terminal, will impact call quality.
The diagram below illustrates the ZL38065 VEC deployed in
an IP-PBX using a centralized TDM/TSI switching architecture to simultaneously route over 500 voice calls between a
local packet network to other PBXs and the PSTN.
The VEC’s patented software algorithm injects spectrally
matched “comfort noise” onto the line that is adjusted to
match caller background noise and eliminate noise gating
when echoes are cancelled. In comparison, less effective
noise matching results in annoying background noise on the
line that sounds “choppy” to users.
The device also improves performance during double-talk
conditions. Zarlink’s algorithm adjusts to a slow convergence speed once double-talk is detected. The convergence
speed can be slowed by as much as 128 times that of the
fast convergence mode to dramatically improve stability.
The low-density ZL38065 VEC can be configured to offer
32 channels of echo cancellation at 64 ms, 16 channels at
128 ms, or other combinations of channel density and echo
delay.
The ZL38065 consumes only 4.68 mW of power per-channel.
Individual blocks can be turned off when not all channels are
in use to further reduce power consumption.
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Information relating to products and services furnished herein by Zarlink Semiconductor Inc. or its subsidiaries is believed to be reliable.
The products, their specifications, services and other information appearing in this publication are subject to change by Zarlink without notice.
ZARLINK, ZL, and the Zarlink logo are trademarks of Zarlink Semiconductor Inc.
© 2004, Zarlink Semiconductor Inc. All Rights Reserved.
Publication Number PP5888
www.ZARLINK.com