Orban OPTIMOD-FM 8600S, Operating Manual

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4-12
MAINTENANCE ORBAN MODEL 8600S
An analog oscilloscope can be used for a more thorough test. Set the
scope for X/Y operation (i.e., so that it generates Lissajous patterns).
Connect the reference generator to one input and the 8600S’s digital
output to the other input. If correct synchronization is occurring, you
should see an essentially stationary (although complex-looking) Lissajous
pattern as opposed to one that precesses slowly either left or right. This
should be true at any combination of input and output sample frequen-
cies and a thorough test will test every permutation.
This test verifies that for non-identical reference and output sample fre-
quencies (for example, locking a 32 kHz output sample rate to a 48 kHz
wordclock), the output and input sample rates are exactly a ratio of inte-
gers. In the example, the output sample rate is exactly 2/3 of the word-
clock frequency.
A digital oscilloscope is unlikely to work satisfactorily for this test.
D) Connect either a source of 1x wordclock (a TTL-level squarewave at the sam-
ple frequency) or a high-accuracy 10 MHz sinewave or squarewave generator
to the 8600S’s
R
EF
I
N
BNC connector
.
Vary the frequency of the reference in-
put by
±
25 ppm and verify that the 8600S’s output sample rate tracks it. See
the comments in step (C) above.
E) Set the 8600S’s
P
ILOT
S
YNC control to
D
IG
I
N
.
F) Sequentially apply AES3 or AES11 signals having 32kHz, 44.1 kHz, 48 kHz, 88.2
kHz, and 96 kHz sample frequencies to the 8600S’s AES3 Digital Input. Using
the oscilloscope technique described in step (C) above, verify that for each in-
put sample frequency, any 8600S output sample frequency (as set via the
DO
R
ATE control) will lock to any reference sample frequency.
G) Disconnect the generator from the 8600S’s
R
EF
I
N
connector.
H) Set the
P
ILOT
R
EF
control to
I
NTERNAL
.
9. Test the 8600S’s stereo encoder.
A) Connect an accurate stereo monitor like the Belar FMMS-1 (“Wizard”) stereo
demodulator to the
C
OMPOSITE
O
UTPUT
1
BNC on the 8600S’s rear panel.
NOTE: The recommended Belar monitor is the only instrument we have
encountered that can accurately measure the performance of the 8600S’s
stereo encoder. With most older-technology monitors, you will be meas-
uring the performance of the monitor, not the 8600S’s encoder. (Of
course, we have not evaluated every monitor on the market.) While we
have not yet tested it, we are confident that the Belar FMCS-1 (a newer
model than the FMMS-1) will also work correctly.
B) On the 8600S, navigate to
Setup > T
EST
.
C) Set the
M
ODE
to
T
ONE
.
D) Set the test tone parameters as follows:
T ONE F REQ ..........................................................................................400 Hz
T ONE L VL ................................................................................................ 91%
T ONE C HAN ............................................................................................... L+R
P ILOT ......................................................................................................... On