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Is the optical power meter reading positive or negative
Although OPM testers measure a negative number for loss, it is conventionally said as a positive number. For example, if the optical power meter reading is “-3. Fiber Optic Measurement Units: "dB" and "dBm" Whenever tests are performed on fiber optic networks, the results are displayed on a power meter, OLTS or OTDR readout in units of “dB. It's very useful in many jobs, especially in communications, fiber optics, andelectronics. Other general purpose light power measuring devices are usually called radiometers, photometers, laser power. Negative dB means division, so -10 dB means a factor of 1/10th (10 times log10 0. 0 dB" signifies a loss of 3.