Grass Valley 3400 CopperHead - Manual (Page 75)

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CopperHead 3400
User Guide
Using the Digital Displays
A Brief Guide to Measurement of Fiber Optic Signal Strength
The CopperHead 3400 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 3400 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 3400 system can optimally work over 24 km 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 therefore contribute additional
connector loss.
The CopperHead 3400 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 3400 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).