OPTIMOD-AM DIGITAL
INSTALLATION
2-35
B)
Make sure that the oscilloscope is synchronized to the square wave.
C)
Turn on the carrier. Observe the RF envelope at the common point with a DC-
coupled oscilloscope and trim the
T
ONE
L
VL
control (if necessary) to produce
30% modulation.
D)
Navigate to
S
ETUP
>
M
ODIFY
TX
P
RESET
>
TX1/D
AY
.
E)
If necessary, press
N
EXT
until you see the screen containing the four L+R
transmitter equalizer controls.
To avoid overheating the transmitter, perform steps (C) through (G) quickly.
Adjustment of the high frequency transmitter equalizer controls cannot be done
into a dummy load because the transmitter will overshoot and ring differently
when loaded by the reactance of your antenna system.
F)
Set the L+R HF
and L+R HF FR controls to
O
FF
.
If no overshoot is observed, skip to step (H).
G)
Adjust the L+R HF
and L+R HF
controls to minimize ringing and over-
shoot.
The L+R HF DELAY and L+R HF FR controls interact. First, adjust the L+R
HF FR control until any ringing is reduced to the same level as the flat
part of the square wave (you will still have ringing, but no overshoot).
Then adjust the L+R HF DELAY control (which will further reduce the am-
plitude of the ringing on the leading edge of the square wave while in-
troducing a new ring on the trailing edge) until the amplitude of the
ringing at the leading and trailing edges is equal. The peaks of the ring-
ing at both edges should approach the flattop modulation level as closely
as possible without exceeding it. Note that the L+R HF FR control does
most of the work.
Note also that the L+R HF DELAY control will produce little or no visible
effect until you set it beyond
40
.
Adjusting the L+R HF DELAY control like this usually reduces the level of
the ringing to below the flattop modulation level. Reducing the setting
Figure 2-11: Unequalized RF envelope
(showing ringing)
Figure 2-12: RF envelope showing
successful HF equalization
Summary of Contents for Optimod-AM 9400
Page 1: ...Operating Manual OPTIMOD AM 9400 Digital Audio Processor Version 1 2 Software...
Page 7: ...Operating Manual OPTIMOD AM 9400 Digital Audio Processor Version 1 2 Software...
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Page 261: ...OPTIMOD AM DIGITAL TECHNICAL DATA 6 29...
Page 267: ...OPTIMOD AM DIGITAL TECHNICAL DATA 6 35 CPU Module...
Page 273: ...OPTIMOD AM DIGITAL TECHNICAL DATA 6 41 RS232 BOARD PARTS LOCATOR...
Page 275: ...OPTIMOD AM DIGITAL TECHNICAL DATA 6 43 8300 POWER SUPPLY PARTS LOCATOR...
Page 284: ...6 52 TECHNICAL DATA ORBAN MODEL 9400 DSP BOARD PARTS LOCATOR DRAWING 32170 000 14...
Page 292: ...6 60 TECHNICAL DATA ORBAN MODEL 9400 DISPLAY BOARD PARTS LOCATOR...
Page 293: ...OPTIMOD AM DIGITAL TECHNICAL DATA 6 61 DISPLAY BOARD...