Santec PEM-320, Operation Manual

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PEM-320 Operation Manual
4-2
After amplification the detected signal is converted to a digital format to enable the measured
parameters to be calculated by the unit's microprocessor. The diagram on the previous page shows the
sine-wave signal obtained as the polarizer rotates. One measurement period corresponds to a 180˚
rotation of the polarizer. PER is calculated as the ratio of the maximum and minimum signals in any
one measurement period and the polarization angle is determined by detecting the position of the
polarizer at minimum transmission. The PEM-320 displays a polarization angle of zero when the
polarization axis is vertical and aligned with the alignment notch of the input connector.