Digital Signal Processors Digital Network Echo Cancellers Processor moving window. This 24 ms window is StarCore™ Family of Digital Signal sufficient to handle the multi-reflective echo Processors from Freescale paths in G.168 (2002) and others that are expected to be encountered in the network. Introduction The echo path delay of the echo canceller Freescale echo cancellation solutions is runtime configurable, from 8 ms up to include a set of network echo cancellers 128 ms, so users may choose a proper for various market requirements and configuration to meet the need of echo path applications. Equipped with Freescale configurations (or spans) and the resource technologies, the solutions offer budget in per channel data memory and carrier-class echo cancellation service for processing load million cycles per packet telephony networks. The echo > Rapid initial convergence rate (echo cancelled within 50 ms) > Far-reaching and stable infinite convergence depth second (MCPS). cancellers are designed to cover up to Features Freescale Semiconductor’s* echo cancellation solutions are robust, field-proven implementations with more than 15 years global deployment into Tier 1 carrier-class telecommunications infrastructure products. The echo cancellers are based on normalized LMS adaptive algorithms and have the following major features: 128 ms echo path delay with one 24 ms > Intelligent near-end talk signal detection mechanism > Adaptive nonlinear processor with optional comfort noise matching FREESCALE ECHO CANCELLER BLOCK DIAGRAM > Innovative mechanism for near-end background noise handling Sin (signal from near end) Echo Delay HPF Error Signal + + Sout (signal to far end) Nonlinear Processor - > Runtime configurable echo-span coverage from 8 ms up to 128 ms Echo Estimate Hybrid Echo Near End Double Talk Detector Pure Delay Estimator Adaptive Filter > Effective background processing for divergence prevention > Fast mid-call convergence (i.e., re-convergence upon hybrid change in the middle of a call) Echo Canceller Controller Delay > Four configurable comfort noise matching levels HPF > Smart handling of signaling tones Delay Rout (signal to near end) Rin (signal from far end) Freescale IPs *The Semiconductor Products Sector of Motorola, Inc. became Freescale Semiconductor, Inc. in 2004. The echo cancellers are ITU-T G.168 (2000/2002) compliant, and systematically evaluated with Freescale voice quality evaluation techniques and by independent expert groups. NETWORK ECHO CANCELLERS Two-Wire Side Four-Wire Side Four-Wire Side Voice Gateway Hybrid Echo Voice Gateway DE PAC PAC VC JB VDC Packet Network ECAN VDC JB Two-Wire Side DE PAC ECAN PAC Echo Hybrid VC Near End Far End VC-voice coder VDC-voice decoder PAC-packetizer DEPAC-depacketizer JB-jitter buffer FREESCALE ECHO CANCELLER IS RUNTIME CONFIGURABLE AND THE CONFIGURATION OPTIONS ARE: Option Echo Span Coverage Window Size Window Type Interfaces The individual software function is supplied as a single library module, 1 128 ms 24 ms Moving window which contains the necessary object 2 64 ms 24 ms Moving window code required to link into a user’s Moving window top-level application code. Essential 3 32 ms 24 ms 4 24 ms 24 ms Fixed window functions are equipped with C 5 16 ms 16 ms Fixed window callable interfaces. 6 8 ms 8 ms Fixed window Availability Available today. PERFORMANCE Echo Span Data Memory (bytes) Option Mean Processing Load (MCPS) Max Processing Load (MCPS per 5 ms frame) Other Documents The following documents are available 128 ms 4064 N* 2.4 N* 4.0 N* upon request. Please contact your 64 ms 2784 N* 2.4 N* 4.0 N* sales representative. 32 ms 2144 N* 2.4 N* 4.0 N* 24 ms 1888 N* 2.1 N* 3.7 N* 16 ms 1376 N* 1.8 N* 3.4 N* 8 ms 864 N* 1.5 N* 3.1 N* • Freescale Echo Cancellation White Paper • Independent Third-Party Testing Results (under NDA) • Freescale Echo Canceller Benchmarking Summary (under NDA) • Freescale Echo Canceller G.168 Test Coverage and Results (under NDA) • Freescale Echo Canceller Interface Control Document (under NDA) • Freescale Echo Path Channel Identification White Paper (under NDA) • Freescale Echo Canceller Evaluation User’s Guide (under NDA) *N is the number of channels. Learn More: For more information about Freescale products, visit www.freescale.com. Freescale™ and the Freescale logo are trademarks of Freescale Semiconductor, Inc. All other product or service names are the property of their respective owners. © Freescale Semiconductor, Inc. 2004 ECHOCANCELFS REV 5