Zarlink simplifies hands-free communication system design

Available now, the ZL38005 voice processing platform integrates dual channel narrowband codecs, on-chip memory, multiple interfaces and advanced voice processing firmware. Supported by a range of design tools, the voice processor improves voice quality, minimises background noise and reduces system complexity and cost.

With this new product, Zarlink now offers a complete portfolio of hands-free voice processing solutions. The new ZL38005 device delivers high-quality voice processing performance and is an easy-to-implement solution for mainstream hands-free communication systems. The previously introduced ZL38004 platform is an enhanced voice processor integrating advanced firmware and functionality for high-end hands-free communication systems. Zarlink also offers the lightly featured ZL38002 digital echo canceller for basic hands-free communication.

Zarlink’s voice processing family is supported by a range of design tools that remove system-tuning complexity, help speed design time and shorten time-to-market. Zarlink’s design tools include a complete evaluation board, and a mini-evaluation board that fits directly into a speakerphone plastic enclosure to provide quick and easy performance testing. Zarlink’s diagnostic tool kit supports simple “plug and test” capabilities to easily measure echo profile, frequency response and distortion. Zarlink also offers a bluetooth evaluation kit for advanced hands-free car kits.

The ZL38005 hardware platform and integrated ZLS38501 firmware ensure hands-free voice quality in severe noise conditions. For example, conference phones must cope with background noise, sound reverberation due to poor plastic enclosure design and acoustic coupling between the microphone and speaker. Car kit designers must provide solutions that support high-quality voice despite severe noise conditions caused by engine, tire and wind noise.

The ZL38005 platform includes narrowband codecs with input/output sampling of 8 KHz, and integrated acoustic and line echo cancellers with programmable echo tail up to 256 ms and noise reduction up to 20 dB.

The device delivers exceptional performance is double-talk situations. Most commercial voice processing solutions fall back to half-duplex operation during double-talk, meaning voice signals pass in only one direction. During double-talk only the signal with the highest strength is transmitted. This results in a choppy and unnatural conversation.

In comparison, Zarlink’s ZL38005 voice processor algorithm is able to continuously converge and track changes in the echo path to support full-duplex operation. Designed in to hands-free desktop speakerphone, for example, Zarlink’s voice processing solution continuously converges, actively tracks echo and adapts to the changing echo path. Poorly designed voice processing solutions will stop tracking echo during double-talk situations. A lower-quality algorithm will readapt when double-talk ceases, creating an audible burst of echo.

The ZL38005 voice processing platform is available now in a 14x14 mm, 100-pin lead-free QFP package.