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DSTR-20
I
M
USL/B.A.C.P.
NSTRUCTION
ANUAL
Reader Alignment
SR.D VIDEO DISPLAY
FIGURE 3
The reader is shipped pre-aligned for 4.5 volts Video output. The following procedure
requires a wide bandwidth oscilloscope (20 MHz or better) and may be used to
verify correct initial operation and also to troubleshoot the unit should service be
required in the future. Focus and video output level may be easily adjusted using
only this instrument. A laptop with Dolby
DRAS software may also be used to
measure and display data about the reader and the film being run.
Connect the oscilloscope to Dolby
Digital processor as follows: connect scope
channel 1 probe to Video test point and its ground test probe to the ground test point.
Connect scope channel 2 to the Clamp test point.
Set scope channels 1 and 2 to 1 Volt sensitivity, DC coupling, calibrated.
Set horizontal sweep rate to 2 us/division.
Run Cat. No. 69T film loop to generate a video signal.
Adjust scope trigger level to stabilize on the clamp signal.
Adjust horizontal position to inside edge of left clamp signal with the scope's left
screen graticule.
Adjust horizontal sweep vernier to line up inside edge of the right screen clamp
signal with right screen graticule as shown in Fig. 3.
Adjust the scope channel 1 vertical position so the bottom of the video display is
even with the lowest horizontal graticule. The video output level should be
comfortably above 2 Volts for proper operation.
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