The present invention relates to a method for providing noise fill in a communication system. The method comprises the detecting (16) of active and inactive information signal transmission periods to a destined end user, and the measuring (17) of background noise normally found in the transmission of...http://www.google.com.hk/patents/US4864561?utm_source=gb-gplus-share專利 US4864561 - Technique for improved subjective performance in a communication system using attenuated noise-fill
