Combined systems for noise reduction and echo cancellation

The performance of three different combined systems for noise reduction and acoustic echo cancellation is compared in this paper. This comparison is made in the specific context of hands-free radiotelephony in cars, where both noise and acoustic echo highly degrade speech quality. This article shows that the best system is based on a cascaded combination of a conventional echo canceller with a filter reducing noise and residual acoustic echo. Nevertheless, recent novel approaches based on the use of a single Wiener filter are to be efficient enough in the specific context of hands-free sound pick-up in cars.