Grass Valley 3404 CopperHead - Manual (Page 71)

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CopperHead 3404
User Guide
A Brief Guide to Measurement of Fiber Optic Signal Strength
The CopperHead 3404 Transceiver System operates within a defined fiber optic link margin,
based on two factors:
• Output (or "launch") power of the optical transmitter at each end of the link: typically -
7dBm*
• Sensitivity of the optical detector at each end of the link: typically -22 dBm.
Fig. 6-4: CopperHead Fiber Optic Link Margin
The overall link margin (or dynamic range) of the CopperHead 3404 system (the difference
between the transmitter's output power and the receiver's sensitivity) is typically 15dB.
That margin is consumed by two main factors:
• Optical loss over the length of the fiber cable: typically 0.5dB per kilometer
• Optical loss at connection points: typically 1 dB per connector
Therefore, a CopperHead 3404 system can optimally work over 24 kilometers of cable
(spending 12 dB of the link budget), and three connectors (spending 3 dB of the budget).
However, adding additional devices, such as the HDX or MPS power supplies, or the
camera-mounted PowerPlus will add connectors, and contribute additional connector loss.
The CopperHead 3404 Transceiver System provides direct digital readout of the Fiber Optic
Link signal strength for both the Base-to-Camera link and the Camera-to-Base link.
The digital readouts on both the CopperHead 3404 Base Station and Camera Unit provide
direct signal strength measurements in dBm. These readouts also provide a wide range of
diagnostic information. The use of the digital readouts is described below.
*The unit "dBm" is an abbreviation for the optical power measured in decibels referenced to
one milliwatt (mW).