Moog Focal 903, Руководство пользователя

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903-0628-00 Rev. 1 Model 903-HD User's Guide – FMB-X-2.5
Focal Technologies Corp. Page 6-6
6.4 Bench Test for Model 903 Systems
BASIC LINK OPERATION (FMBs)
1. Basic operation of the uplink (remote to console) and downlink (console to remote) can be verified in a
bench test simply by connecting the test jumper and the 10 dB attenuator supplied between a bushing on
the remote FMB-X-2.5 turret and a bushing (F1 or F2) on the console FMB-X-2.5. The fiber switch should
either be in automatic mode or manually switched to the correct bushing.
2. A green “Link” LED on the console FMB-X-2.5 indicates a valid uplink and is lit when data frames are
being transmitted from the remote end. A green “Link” LED on the remote FMB-X-2.5 indicates a valid
downlink and is lit when data frames are being transmitted from the console end.
3. A red “Link” LED indicates either insufficient received optical power or loss of frame synchronization.
Frame synchronization must be re-established before valid data frames are transmitted.
4. Loss of both the uplink and downlink — “Link” and “FO-RX” LEDs are red at both ends — suggests a
problem with the optics between the two modules, such as a bad connector. (All optical connectors
should be cleaned before use.)
Do not attempt to connect the high optical power FMBs directly with an ordinary fiber jumper. A
minimum loss of 10 dB is required between the front panels of the console and remote units when
using the high optical power FMBs to ensure the receivers are not saturated or damaged.
OPTICAL POWER BUDGET TEST
1. To verify the uplink (remote to console) power budget, measure the 1310 nm transmit power (P1) of
the remote FMB-X-2.5 by connecting one of two bushings directly to a calibrated optical power meter
(PM) using a short, low loss singlemode jumper. Ensure that the optical power meter is set for
1310 nm.
Figure 6-5: Power Budget Test Setup – Transmit Optical Power Measurement
2. With the test jumper included, install a singlemode variable optical attenuator (VOAT) between the
remote and console FMBs plus a 10 dB attenuator. Adjust the VOAT until a “Link” LED on either one
of the modules starts flickering or turns red, then reduce the loss to the point where both “Link” LEDs
are solid green. (Alternatively, video signal quality can be used as a measure of link threshold, since
black speckles will start to appear when the optical link is marginal.) Use of a fixed attenuator with the
VOAT is recommended to avoid accidentally setting the loss too low. The following figure shows a
setup example.