page 4 – 3
D-75 /Sep 2004
OUTPUT MODULE
Internal Programming Options
There are no programming options on the OM-75 output card.
Sampling Frequency for Console Outputs
For stand alone operation, the console output sample rate is determined
by crystal Y1, which is installed
at the factory for a 44.1 kHz
sample rate. An additional crys-
tal oscillator is provided with the
console for the 48 kHz sample
rate. Crystals for the 32 kHz
sample rate are available from
the factory as a special order
item.
To switch to a different out-
put sample rate, replace crystal
Y1 with one of the appropriate
frequency as shown in Figure 1
and Table 1.
TABLE 1
SAMPLE RATE CRYSTAL OSCILLATOR WS PART#
FREQUENCY
48 kHz 24.576 MHz 370012
44.1 kHz 22.579 MHz 370011
32 kHz 16.384 MHz 370010
Note that to replace the crystal Y1 you need to open the meterbridge to
access the PR-75 board.
The console must be powered down before changing the sample rate
crystal Y1 or damage not covered by warranty may result. Changing the
crystal Y1 will change the console output sample rate; however some external
digital devices also need the correct sample rate information to be embedded
in the AES output data or they will not operate correctly. Therefore, after
changing the sample rate crystal Y1, be sure to reset dipswitches SW3 and
SW4 on the PR-75 board to correctly embed the sample rate information in
the output AES data stream. Table 2 shows the dipswitch settings.
TABLE 2
SW3 SW4 FREQUENCY
OFF OFF 48 kHz
ON OFF *44.1 kHz
OFF ON 32 kHz
*default setting
Figure 1. Section of the PR-75 PCB
SW3 SW4
D-75 /Nov 2009
!
Note, the console sample rate
can also be synchronized to an
external sample rate source.
See page 10-5 for details.
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