Sennheiser MI 1000 Instructions for Use - Page 2

USER'S GUIDE MI 1000 General The infrared meter MI 1000 was designed for measuring the useful infrared light in an infrared system. The measurement is to a large extent free from the in- fluences of unwanted light. Sunlight, spotlights and other sources of very strong unwanted light should, however, be avoided. The MI 1000 selectively measures that part of the infrared light which is modulated by the RF carrier and indicates this on a wide logarithmic scale. In this way one can determine whether a given infrared system has been under- or overdimensioned and whether certain spots in the room are being insufficiently illuminated. When measuring multi-channel systems all of those ~ channeffiwhich will later come into use should be switched on. The measurement should preferably be carried out on channel 2 (95 kHz). Channel 2 of the MI 1000 corresponds to channel 2 of the 9-channel system. Moreover, in this setting measurements can be carried out on infrared mono systems and the left channel (95 kH~: of a stereo system. Wideband mono- and stereo systems should not be AF modulated during the measuring process as this would only result in the narrow band infrared meter giving false readings. °Reration a) Set channel selector to position 2 b) Press red button c) Position of the lens should correspond to the normal position of the receiver d) Read the meter A table on the back of the unit shows which S/N ratios are to be expected. A deflection of 7 means good reception quality. ~ A weaker deflection means that there is too little useful infrared light and ~ that therefore the quality of reception is not so good. A deflection of more than 7 means that the number of radiators can be reduced or that the radiators already present should be pointed at places in the room which are not so weIl illuminated. Monitoring output It is possible to connect headphones (Z~ 200 Q) to the 3,5 mm jack socket. This means that while measuring one can listen to the residual noise or (with 9-channel systems only) the AF modulation. Changing the batteries If during the course of the measuring process the red LED should light up, this means that the batteries are exhausted. The small panel situated directly below the lens should be unscrewed and the batteries changed.