1-20
INTRODUCTION
ORBAN MODEL 9300
Transmission Levels
The transmission engineer is primarily concerned with the peak level of a program
to prevent overloading or overmodulation of the transmission system. This peak
overload level is defined differently, system to system.
In FM modulation, it is the maximum-permitted RF carrier frequency deviation. In
AM modulation, it is negative carrier pinch-off. In analog telephone/post/PTT trans-
mission, it is the level above which serious crosstalk into other channels occurs, or
the level at which the amplifiers in the channel overload. In digital, it is the largest
possible digital word.
For metering, the transmission engineer uses an oscilloscope, absolute peak-sensing
meter, calibrated peak-sensing LED indicator, or a modulation meter. A modulation
meter usually has two components — a semi-peak reading meter (like a PPM), and a
peak-indicating light, which is calibrated to turn on whenever the instantaneous
peak modulation exceeds the overmodulation threshold.
Line-Up Facilities
Metering of Levels
The meters on the 9300 show left/right input levels and both positive and negative
output modulation.
Input metering is stereo because the 9300 will most often be fed by a ste-
reo source even though the 9300 processing is mono.
Left and right input level is shown on a VU-type scale, while the metering indicates
absolute instantaneous peak
(much faster than a standard PPM or VU meter). The
input meter is scaled so that 0 dB corresponds to the absolute maximum peak level
that the 9300 can accept. If you are using the AES3 digital input, the maximum digi-
tal word at the input corresponds to the 0 dB point on the 9300’s input meter.
Built-in Calibrated Line-up Tones
To facilitate matching the output level of the 9300 to the transmission system that it
is driving, the 9300 contains an adjustable test tone oscillator that produces sine
waves at 9300’s (analog or digital) left and right outputs. The frequency and modu-
lation level of the line-up tones can be adjusted from the front panel (as described
in
You can adjust the frequency and modulation level of the built-in line-up tone. You
can use the front panel, the PC Control software, or the opto-isolated remote con-
trol interface ports to activate the Test Tone.
Built-in Calibrated Bypass Test Mode
A
BYPASS
Test Mode is available to pass line-up tones generated earlier in the sys-
tem. This mode applies a DC servo, a highpass filter, a 15 kHz lowpass filter, a safety
Summary of Contents for OPTIMOD-AM 9300
Page 1: ...Operating Manual OPTIMOD AM 9300 Digital Audio Processor Version 2 0 Software...
Page 7: ...Operating Manual OPTIMOD AM 9300 Digital Audio Processor Version 2 0 Software...
Page 178: ...3 46 OPERATION ORBAN MODEL 9300...
Page 200: ......
Page 221: ...OPTIMOD AM DIGITAL TECHNICAL DATA 6 21...
Page 222: ...6 22 TECHNICAL DATA ORBAN MODEL 9300 CONTROL BOARD PARTS LOCATOR...
Page 228: ...6 28 TECHNICAL DATA ORBAN MODEL 9300...
Page 229: ...OPTIMOD AM DIGITAL TECHNICAL DATA 6 29 I O DSP BOARD LEFT AND RIGHT ANALOG INPUTS...
Page 230: ...6 30 TECHNICAL DATA ORBAN MODEL 9300 I O DSP BOARD ANALOG OUTPUTS...
Page 231: ...OPTIMOD AM DIGITAL TECHNICAL DATA 6 31...
Page 238: ...6 38 TECHNICAL DATA ORBAN MODEL 9300 FRONT VIEW REAR VIEW FRONT PANEL PARTS LOCATOR DIAGRAM...