ACTIVE NOISE CONTROL FOR CREATING A QUIET ZONE AROUND A MOBILE PHONE FOR NOISELESS SPEECH COMMUNICATION

摘要

Active Noise Control for Creating a Quiet Zone around a Mobile Phone for Noiseless Speech Communication Abstract Active noise control (ANC) is emerging as an effective technique for nullifying noise. Conventional passive methods using barriers are found ineffective in low frequency noise (= 500Hz). In mobile telephony it is difficult to attend incoming telephone calls in a noisy environment such as in market places, transport vehicles etc. Conventional methods cannot be applied in such situations, but noise can be eliminated electronically using ANC. Present invention relates to the findings by computer simulation that the speech signal whose SNR is above or equal to 3 dB do not lose their intelligibility in the quiet space created by the ANC system. Extensive experiments have been performed for verifying the above result using the developed Two stage FxNLM algorithm based ANC system. The results revealed that an ANC system embedded in a mobile phone enable a noiseless speech communication in a noisy environment.