USL, Inc.
JSD-80 Instruction Manual
Page 26
3rd Edition. February, 2006
The graph below shows a reader with an
azimuth error. The rising lower curve shows
the phase difference between left and right
channels. This is similar to a lissajous pat-
tern on an oscilloscope where an ellipse in-
dicates a poor alignment. The oscilloscope
pattern is actually less accurate than the
difference display. In the lissajous pattern,
all the frequencies are added together so a
phase difference at 20 kHz is less obvious.
The difference display on the RTA shows the
phase difference at each frequency.
8.4 Mono EQ and Bypass Level
1. Click on the INPUT tab and select
MONO format. Thread a pink noise
loop on the projector. Using the SLIT
EQ Analyzer, adjust the MONO EQ until
the above curve is achieved.
2. Set the bypass level by adjusting trim-
pot (1) until the voltage on the bypass
level test point (8) reads 300 mV rms.
Repeat the procedure for Projector
2 using trimpot (2). When the JSD-80
power switch is in the “off” position
and the emergency backup power
supply is present the main fader will
control the bypass level.
8.5 Optical Surround Gain and
Delay
1. Click the INPUTS tab and thread a
Dolby Cat 151 test fi lm on the projec-
tor.
2. Mute the screen channels and, using
an RTA or SPL meter, adjust the SURR
GAIN in the MATRIX CONTROLS so
that the SPL level in the back matches
the SPL level in the front. The SURR
DELAY slider should be at 10 ms.
3. Calculate the surround delay by using
the following formula:
Length of theatre - (width of theatre/2)
+20 = Delay in ms
4. Set the SURR DELAY control accord-
ingly.
8.6 Optical Subwoofer
See Section 9.5
8.7 Analog Non-Sync, AUX
Levels, MIC Levels
1. Set main fader to 7.0. Connect the
sound source to the NON-SYNC L and
R RCA jacks. Click on the INPUTS tab.
Select the NON-SYNC format. Adjust
the left slide pot and both channels
will change. The master fader should
be set at 7.0.
2. Set main fader to 7.0. Connect the
sound source to the AUX L and R RCA
jacks. Click on the INPUTS tab. Select
the AUX format. Use the main left and
