Each input of the multi-channel Acoustic Echo Canceller (AEC) shall have its own acoustic echo canceller and ambient noise canceller on up to eight (8) individual inputs. Acoustic echo cancellation on each channel shall be fully automatic in operation and shall not use any tones or noise in order to establish AEC convergence. AEC convergence shall be no slower than 30dB / second. The AEC shall have a minimum echo cancellation span of 200 ms per channel. The AEC shall operate at room gain levels of up to 10dB and a minimum total echo cancellation of 65dB. In addition to providing acoustic echo cancellation on each input, the unit shall provide 6 or 10 dB (user selectable) of ambient noise cancellation on each input. The noise cancellation shall effectively cancel steady-state ambient noise at all frequencies without causing any perceptible degradation of human voice or other transient sounds. The unit shall be capable of canceling noise on eight channels of full-band (20kHz bandwidth) audio when the AEC is disabled on all channels.
Individual line level outputs shall be available for each of the inputs. The unit shall accommodate Record and Playback signals. The multi-channel AEC shall be capable of feeding the individual inputs of an automatic microphone mixer (AMM) at a nominal level of 0dBu. Acoustic echo and ambient noise shall be removed prior to feeding the AMM. Inputs shall be configurable for microphone or line level such that any number of inputs from 0 to 8 may be supported at microphone or line level. 28V phantom power shall be available for microphone inputs and shall be switch selectable.
The AEC shall have the capability of splitting inputs and outputs for room zoning or other uses. Splitting shall be user-selectable and shall be configurable from one to seven inputs/outputs for one room, with the remaining inputs/outputs assigned to the second room. The AEC shall be capable of accepting two AEC reference (CODEC) inputs.
Remote control of the unit via RS232 shall be available. The unit shall be capable of linking to additional multi-channel AEC units or other products from the same manufacturer (such as a phone-add) and shall provide a bus for control of all linked units such that all linked units may be controlled through a single RS232 connection.
Audio signals to and from the unit shall be balanced and shall be presented on mini-Phoenix connectors. Serial control and bus connections shall be available on DB9F and RJ45 connectors. The unit shall accept microphone input levels of –33 to –63 dBu or line level inputs of -30 dBu to +0 dBu, with 20dB headroom. Phantom power shall be available on the eight microphone inputs whether they are configured for mic or line level, such that high-output microphones may be accommodated. The unit shall accept reference (codec) input levels of -24dBu to +0 dBu. Line level outputs shall be at +0dBu nominal. Zone output signal levels shall be adjustable from -20 dBu to +0 dBu. The unit shall accept a playback input with nominal level of –10dBV with an adjustable gain of +/- 8dB, and shall provide a record output with nominal level of –10dBV.
The unit shall accept input voltage of 100 – 240 VAC, 50 / 60 Hz and shall consume no more than 40 Watts. The AEC shall be no larger than one rack unit in size and shall comply with the ITU G.167 Recommendation for AEC, FCC part 15, and CE requirements.
The Polycom EF1210 is specified.
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