Product category:
Communications ICs (Wired)
News Release from: Zarlink Semiconductor | Subject: ZL38070 and ZL38065
Edited by the Electronicstalk Editorial
Team on 21 September 2004
Echo cancellers ensure carrier-grade
voice quality
Two new voice echo canceller devices have advanced features to help ensure carrier-grade voice quality for packet-based and cellular networking equipment in high-noise environments.
Two new VEC (voice echo canceller) devices have advanced features to help ensure carrier-grade voice quality for packet-based and cellular networking equipment in high-noise environments Zarlink's 256-channel ZL38070 and 32-channel ZL38065 VECs are high-capacity, low-power devices that use patented nonlinear processing software to deliver improved noise-matching techniques
This article was originally published on Electronicstalk on 7 Feb 2001 at 8.00am (UK)
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Today's VECs must handle voice echo issues that are often emphasised by the longer signal processing and transmission delays associated with packet and wireless networks.
These problems are compounded by excessive background noise that further effects call quality.
"Building on the field-proven success of our voice echo canceller family, our new devices remove echo and ensure that callers are not plagued by annoying changes in background noise, regardless of operating conditions", said Andre Coucopoulos, Product Marketing Manager, Voice Echo Cancellers, Zarlink Semiconductor.
"These VEC chips also deliver significant power savings for equipment manufacturers".
The ZL38065 and ZL38070 VECs improve voice quality in equipment where the convergence of voice and data traffic on a packet network causes processing delays that emphasise echo.
In addition, excessive background noise will affect call quality when equipment is operating in a high-noise environment, such as an industrial setting or airport terminal.
Zarlink's new VEC chips use patented nonlinear processing software that includes several features to improve voice quality.
The software's algorithm injects onto the line spectrally matched "comfort noise" that is adjusted to match caller background noise and eliminate noise gating when echoes are cancelled.
With superior noise matching capabilities, Zarlink's new VECs can handle intense background noise, ensuring seamless voice quality in high-noise situations.
In comparison, less effective noise matching often results in annoying background noise on the line that sounds "choppy" to users.
Double-talk, when two callers are speaking at the same time, poses a unique challenge for VECs as they must distinguish the conversation from background noise.
Zarlink's VECs feature fully programmable per-channel convergence speeds, allowing designers to tailor the performance of the devices to achieve the best double-talk call quality for their application.
The ZL38070 high-density VEC can be configured to offer 256 channels of echo cancellation at 64ms, 128 channels at 128ms, or other combinations of channel density and echo delay.
The low-density ZL38065 device can be configured to offer 32 channels of echo cancellation at 64ms, 16 channels at 128ms, or other combinations of channel density and echo delay.
Consuming only 4.68mW per channel, Zarlink's new VEC chips meet customer requirements for power-efficient echo cancellers.
In addition, individual blocks can be turned off when not all channels are in use, drastically reducing power requirements.
For example, in a mobile switching centre where overall power consumption is a critical design concern, the high-density ZL38070 VEC delivers power efficiency and flexibility advantages.
The ZL38065 and ZL38070 VECs are fully compliant with the ITU-T G.168 (2000) standard for digital echo cancellers and G.164/165 standards for fax/modem transmissions.
Zarlink's newest VEC chips are now in production.
The 32-channel ZL38065 device is packaged in a 100-pin LQFP or 208-ball LBGA and is priced at US $52 in volumes of 1000.
The 256-channel ZL38070 chip is packaged in a 535-ball PBGA and is priced at US $244 in volumes of 1000.
Both devices are fully supported by evaluation boards and reference designs.
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