| 摘要 |
<p>A generation method of Comfort Noise Frames (CNF) in a TETRA system is described, for the generation of background noise frames in an emitter terminal, which must be transmitted during the periods of silence of said emitter terminal. The invention, also applicable to the case of the GSM standard, uses algorithmic alternatives for generating the frames by means of applying an algorithm to the parameters given by the control block terminal vocoder to the vocoder control block, the latter including a Vocal Activity Detector (VAD) and a comfort noise parameters calculation block. The method of the invention foresees the adaptation phases of the GSM standard VAD to that of TETRA, the CNF frame calculation, and the gains averaging by alternating the values of the quantizer, such that the average of the values over the subframes is as close as possible to the desired energy. <IMAGE></p> |
