In hands-free telephony (e.g. mobile phone hands-free Car kit, PC Internet telephony, video-conferencing, hands-free telephones, etc), voice signals from the loudspeaker often appear at the microphone, this causes conversational interference in the form of acoustic echo and howling. These can be eliminated by using simple Acoustic Echo Canceller systems.

The major limitation of existing Acoustic Echo Canceller (AEC) systems is that most systems are only capable of half-duplex communication or muffled full-duplex communication. Even though many existing Acoustic Echo Canceller systems claim to offer full-duplex systems, the quality of speech are greatly compromised.

In BITwave, we have developed a DSP-based AEC system that is capable of handling full-duplex communication, echo cancellation, noise suppression and reproducing crystal clear speech.

By accurately detecting Echos, Near End Speech and Double Talk situations, the BITwave AEC system is able to cancel the Echos accurately and retain the quality of Near End Speech, even during Double Talk Situations.

By continuously monitoring the background noise and using a mathematically-optimised algorithm, the BITwave AEC system is able to accurately estimate and suppress background noise. The advantage of this method compared to simple spectral subtraction is that the quality of the Near End Speech is subjected to minimumal distortions. This method allows a lot more accurate suppression and thus, is able to retain maximum intelligibility than other forms of frequency suppression algorithms.

Together, these technologies produce astonishingly levels of echo suppression and noise suppression never achieved before.