Orban OPTIMOD-FM 5518, Operating Manual

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4-12
MAINTENANCE ORBAN MODEL 5518
Connect the reference generator to one input and the 5518’s digital out-
put 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 frequencies 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 5518’s
R
EF
I
N
BNC connector
.
Vary the frequency of the reference input
by
±
25 ppm and verify that the 5518’s output sample rate tracks it. See the
comments in step (C) above.
E) Set the 5518’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 5518’s AES3 Digital Input. Using
the oscilloscope technique described in step (C) above, verify that for each in-
put sample frequency, any 5518 output sample frequency (as set via the
DO
R
ATE control) will lock to any reference sample frequency.
G) Disconnect the generator from the 5518’s
R
EF
I
N connector.
H) Set the
P
ILOT
R
EF
control to
I
NTERNAL
.
9. Test the 5518’s stereo encoder functionality.
A) Connect an accurate stereo monitor like the Belar FMMS-1 (“Wizard”) stereo
demodulator to the
C
OMPOSITE
O
UTPUT
1
BNC on the 5518’s rear panel.
NOTE: The recommended Belar monitor is the only instrument we have
encountered that can accurately measure the performance of the 5518’s
stereo encoder. With most older-technology monitors, you will be meas-
uring the performance of the monitor, not the 5518’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 5518, 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
You will have to press the
N
EXT button to access all of these parameters.