OPTIMOD-AM DIGITAL
INSTALLATION
2-27
In Region-2 countries, we recommend configuring the 9400 for 9.5 kHz
NRSC-1 lowpass filtering (via the active transmission preset) and the
18dB/octave HF equalizer active with a
G
AIN
of 10dB and a
C
URVE
of 10
(via the active processing preset). This is similar in spirit to the NRSC pre-
emphasis, which also has a maximum gain of 10dB. However, it provides
more midrange boost than the NRSC pre-emphasis, which helps the vast
majority of radios in the field. These are narrowband radios with 2 to 3
kHz audio bandwidth (3dB down). They do not meet the EIA's AMAX
standard (or even come close to it). Of course, if you wish to broadcast
with strict NRSC pre-emphasis, you can easily adjust the 9400's HF Equal-
izer to do this by setting the HF curve to NRSC.
Some broadcasters have now chosen to reduce their output bandwidth
below the NRSC limit voluntarily. Setting the output bandwidth to 7.0
kHz or below in a transmission preset will automatically invoke the nar-
rowband versions of the factory presets. However, it will not change a
user processing preset.
For countries where narrowband lowpass filtering is required, we rec-
ommend setting OPTIMOD-AM’s lowpass filter to 6.0 kHz. This will meet
the requirements of ITU-R 328-5 without further lowpass filtering in the
transmitter. Any such lowpass filters already in the transmitter should be
removed to prevent overmodulation caused by the filter's overshoot and
ringing.
Figure 2-8: Effect of the LPF Shape Control with F = 5.0 kHz
C)
Hold down the soft key under
LPF
S
HAPE
and turn the knob to determine
whether the input lowpass filter is down 0.1 dB, 3 dB, or 6 dB at the lowpass
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...