Yamaha V4.0 DME Designer V4.0 Owners Manual - Page 483

Chapter 6 Component Guide MY4-AEC Signal Flow The local and remote locations in a teleconferencing system are referred to as the "near end" and "far end", respectively. The MY4-AEC acoustic echo canceller (AEC) works by comparing the reference signal received from the far-end with the signal from the microphone in order to determine which components of the signal are echo, and then subtracts only the far-end echo component from microphone signal. The near-end sound is thus clearly transmitted to the far end without echo From Far-end A NR From Far-end B NR From Far-end C NR From Far-end D NR Matrix Router Far-end Voice A Far-end Voice B Far-end Voice C Far-end Voice D To Far-end 4 NR AEC Near-end Mic. 4 FBS Near-end Voice 4 To Far-end 3 NR Near-end Mic. 3 AEC FBS Near-end Voice 3 To Far-end 2 NR Near-end Mic. 2 AEC FBS Near-end Voice 2 To Far-end 1 NR Near-end Mic. 1 AEC FBS Near-end Voice 1 Reference signal FBS: Feedback suppressor NR: Noise reduction  NR (Noise Reduction) Automatically detects and reduces constant environmental noises such as projector fans or air conditioning.  FBS (Feedback Suppressor) Automatically detects the frequencies at which feedback is occurring and applies notch filters at those frequencies to stop the feedback. 42 notch filters are available for each AEC channel. The notch filters are reset (i.e. returned to "not applied" status) when the DME64N/24N power is turned off. DME Designer Owner's Manual 483