Monday, July 2, 2007

Zarlink Expands its Voice Echo Canceller Line

Zarlink Semiconductor has expanded its VEC (voice echo canceller) product portfolio with a hardware and firmware platform aimed at helping network equipment manufacturers simplify design, speed time-to-market and lower bill-of-material and resource costs.

Zarlink's ZL38015 voice processing platform is built on a voice optimized 100 MHz (200 effective MIPS) DSP with an integrated 1024 tap filter co-processor, 16 KW instruction and 8 KB data memory, hardware accelerators, SPI (serial peripheral interface), UART (universal asynchronous receiver/transmitter) and TDM (time division multiplexing) interfaces, multiprotocol TDM ports, flexible clocking scheme support and 10 GPIOs (general purpose input/outputs).

The ZLS38233 is a four-channel VEC with echo tail programmable up to 64 ms per channel. Where competing solutions will often employ windowing algorithms in the DSP to locate and cancel peaks in echo profiles, the ZLS38233 VEC supports full band echo cancellation. Zarlink said windowing algorithms may not detect multiple echo paths in a signal, resulting in incomplete echo cancellation. In addition, echo tails outside the windowing algorithm may not be cancelled. In comparison, the ZLS38233 VEC eliminates echo from 0 ms to 64 ms without compromise.

The ZLS38233 firmware also integrates a flexible DTMF (dual-tone multi-frequency) transmit programmable tone generator that can generate dual DTMF or single tones, with burst mode support from zero to four seconds and programmable output gains from -18 db to 24 db in 6 db steps to allow for the generation of DTMF, CNG (comfort noise generator), central office and other telecom signaling functions.