Studer d 19 echo canceller brochure

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D19 Echo Canceller E 2 Edition: 29.07.9 STUDER Echo Canceller The Echo Canceller has been designed to over- come problems in live broadcasting, when trans- mission delays due to digital transmission and data compression processes do not allow using the broadcast signal as monitoring source. When switching between different channels dur- ing on-air programs, the local reporters should be able to monitor the final broadcast signal to keep the overview and react to forced switchings due to more important events on other channels (e.g. sports events).For listening to the current program without be- ing disturbed by the own delayed voice, the echo of the local signal has to be deleted from the re- turn signal. The delay range of currently available echo sup- pression products like telephone hybrids is not sufficient for these situations (some 100 ms). The Echo Canceller is using a separate delay line which allows to remove echo signals up to one second. This pre-delay either adapts to the cur- rently measured delay automatically, or it can be set manually for fixed installations. After being removed from the returning broad- cast signal, the local source can be directly added again. The volume of this direct signal is adjustable, and it is added automatically when a return signal is present.

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D19 Echo Canceller E 3 Edition: 29.07.9 1. Operation T he E cho Canceller is ope rated locally with a few frontpanel elements. A serial remote port will be available as option. In addition to the power switch, the following elements are pro- vided. A 3-digit display indicates the currently selected pre-delay in the range of 0-¦999 ms. With the MODE key, one of the following oper- ating modes can be selected: CONT In continuous mode the predelay circuit is adapting automatically to the current situation. It is looking for a correlation between local and return signal; the delay line is modified after two valid measurements in sequence. MAN The manual mode allows to set the pre- delay with an UP and a DOWN key, which increment or decrement the cur- rent delay. ONCE The one-shot mode is setting the delay line once. After the first two valid meas- urements in sequence the delay will re- main constant. The return signal may be bypassed to the LOC AL OUT output with the BYP key. With the DIRECT V OLUME potentiometer, the volume of the directly added local signal is ad- justed from mute to full level position. A LOCK indication is switched on during cor- rect operation of the unit. Whenever no correla- tion is found or the delay time is being modified, the LOCK indication goes off.