Grass Valley T-POV Bidirectional Robotic - Manual (Page 70)

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Operation of the T-POV System
A Brief Guide to Measurement of Fiber Optic Signal Strength
A Brief Guide to Measurement of Fiber Optic Signal Strength
The T-POV Optical Link 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.
The following diagram illustrates the Fiber Link transmission range related to Optical Power
Fig. 6-1: T-POV Fiber Optic Link Margin
The overall link margin (or dynamic range) of the T-POV 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 Tactical Fiber T-POV 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).
The T-POV 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 unit "dBm" is an abbreviation for the optical power measured in decibels referenced to
one milliwatt (mW).