Powerware Model V-2000B 사용자 설명서

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페이지 137
 
 
 
Maintenance = 107 
Audio Level Calibration 
The input gain and output gain of the analog audio circuits are factory calibrated to a +4 dBu 
standard.  Each circuit includes a trim pot with a range of approximately ±2.5 dB.  The following 
procedures may be used to calibrate these for unity gain.  Each trim pot is located above the XLR 
connector with which it is associated.  Refer to the preceding drawing (Figure 27) for the location 
of trim pots and jumper blocks referred to in the calibration procedures. 
Calibration Procedure 
This procedure assumes that the technician is fully familiar with test procedures employing the 
Audio Precision® test equipment, or its equivalent. 
1.  Position the jumper block J5 and J6 for Channel 1 output to obtain an analog output. 
2.  Play the test clip titled zTONE present on the Image Server disk.  This stereo clip is 
recorded at a level equivalent to a +4 dBu output level. 
3.  While observing the output level of audio Channel 1 Left, adjust trimmer RV4 until a level 
of exactly +4.00 dBu is obtained. 
4.  Repeat this procedure for audio Channel 1 Right, while adjusting trimmer RV3, and also for 
each subsequent audio channel using its associated trim pot. 
Having established accurate gain settings for all analog audio outputs in steps 1 through 3 
above, calibrate the Imag e Server’s input gain as follows: 
5.  Using the graphic user interface, place server Channel 1 in the E-E mode, so that an input 
signal will appear at its output. 
6.  While observing the output level of audio Channel 1-L, apply a 1 kHz sine wave from the 
audio generator to audio Input 1-L.* 
7.  Adjust input trimmer RV2 until a level of exactly +4.00 dBu is obtained at the output of 
Channel 1L. 
8.  Repeat this procedure for audio Input 1-R, making the gain adjustment with input trimmer 
RV1. 
The preceding steps establish a gain of unity through the server. 
* In the absence of a generator, use the calibrated outputs of Channel 2 playing zTONE to 
feed the inputs.