| 摘要 |
A Comfort Noise Generation (CNG) system is provided for use in open systems where there is no predefined protocol for transmission of Silence Insertion Descriptor (SID) information from transmitter to receiver. The receiver enters an underrun condition in response to periods of silence, and in response generates comfort noise. According to the present invention, the computation of the level and spectral characteristics of the background of the speech signal is done within the receiver, thereby overcoming the lack of a protocol to transmit the SID information during silence periods. These characteristics a re computed as a gain parameter and a set of Linear Prediction Coding (LPC) parameters which are applied to a filter which filters flat-spectrum noise in order to generate noise that sounds like the background noise of the speech signal.
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