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Because the impulse response of an acoustic echo path may be several hundred milliseconds long, acoustic echo cancellation is a long-standing problem and hasn't been solved effectively. In order to solve this problem, in this paper an acoustic echo canceller is presented and a new self-orthogonalizing alternative constrained partitioned frequency-domain block LMS (PBFLMS) algorithm is put forward. This algorithm has good convergence ability, small misadjustment, low computation complexity and small delay. In addition, according to the application of the acoustic echo canceller, this algorithm is modified. Finally the whole echo canceller is implemented by using a single TMS320C30 processor in the ATD-C30 simulator and satisfying results are acquired.

The single chip telephone IC, INCA (INfineon Codec with U/sub PN/ transceiver and embedded microcontroller featuring Acoustic echo cancellation), integrates all the functions necessary for a digital voice and data terminal. With the 2-wire U/sub PN/ analog line transceiver, the INCA implements all subscriber access functions for digital terminals. Key feature of the chip is a smart acoustic echo cancellation and suppression algorithm, which allows comfortable full-duplex speakerphone conversations. Different digital interfaces allow connection to a variety of devices, including a 12 Mb/s USB (Universal Serial Bus) interface for PC host communication. The basic application of the INCA is in terminal equipment, where microphone, loudspeaker, headset and handset can be connected directly to the analog front end. Additionally the INCA provides a mechanism to control other U/sub PN/ terminals. This mode allows one to cascade U/sub PN/ telephones via its IOM-2 (ISDN Oriented Modular) interface. The INCA is a 0.35 /spl mu/ CMOS device and operates with a single 3.3 V supply.