Dsp Circuit; Power Supply - Orban OPTIMOD 6300 Operating Manual

6-10
TECHNICAL DATA

DSP Circuit

Power Supply

3. Digital Sample Rate Converter (SRC) and Output Transmitter
Located on input/output/DSP board
Output sample rate converter (SRC) chips IC400 and IC402 convert the 48 kHz
6300 system sample rate to any of the standard 32 kHz, 44.1 kHz, 48 kHz, 88.2
kHz, and 96 kHz rates for the 6300's Digital Out 1 and Digital Out 2 respectively.
The sample rate converters drive digital audio interface transmitters IC403, IC404,
which encode digital audio signals using the AES3 interface format (AES3-1992).
These chips are surface-mounted and are not field-replaceable.
The DSP circuit consists of four Motorola DSP56367 24-bit fixed-point DSP chips,
which execute DSP software code to implement digital signal processing algorithms.
The algorithms filter, compress, and limit the audio signal. The four DSP chips, each
operating at approximately 150 million instructions per second (MIPS), for a total of
600 MIPS, provide the necessary signal processing. A sampling rate of 48 kHz is used.
System initialization normally occurs when power is first applied to the 6300 and can
occur abnormally if the 6300's watchdog timer forces the SC520 to reboot. Upon ini-
tialization, the SC520 CPU downloads the DSP executable code stored in the flash
memory. This typically takes about 7 seconds. Once a DSP chip begins executing its
program, execution is continuous. The SC520 provides the DSP program with pa-
rameter data (representing information like the settings of various processing con-
trols), and extracts the front panel metering data from the DSP chips.
During system initialization, the SC520 queries the DSP hardware about its opera-
tional status and will display an error message on-screen if the DSP fails to initialize
normally. Please note any such messages and be ready to report them to Orban Cus-
tomer Service.
The DSP chips are located on the I/O+DSP board—see the drawings starting on page
6-29.
Warning! Hazardous voltages are present in the power supply when it is connected
to the AC line. Several parts, including the heat sink, are hot to the AC power line.
Except for servicing, do not remove the insulating shield from the power supply.
The power supply is a modular switching supply to minimize heat buildup and
power consumption. It converts an AC line voltage input to +15, –15, and +5 volts.
All other supply voltages are derived from these three voltages via local regulation.
The supply accepts inputs from 95 to 264 VAC, 50 – 60 Hz.
The only fuse in your Optimod is a 2.5A 20mm Quick Acting HBC fuse mounted on
the power supply's circuit board. Because the supply's outputs are automatically cur-
ORBAN MODEL 6300