Basics of Level Accuracy, Level Linearity, and Level Scale in Optical Spectrum Analyzers
Level Accuracy:
Level Accuracy is a tolerance to the true value of measured value, when a standard level is measured with a standard wavelength.
Level Linearity:
Level Linearity is the width of error dispersion between a measured value and a true value, when multiple levels are measured at a certain wavelength. Similar to wavelength linearity, it specifies a degree of error dispersion, but not an error of absolute level. Therefore, it provides a relative reliability of a level of the spectrum. If there is an error of absolute level, all of the spectrum may be shifted up or down.
Level Scale:
Level Scale is the vertical axis (level axis) setting, when a spectrum is shown on the display. The level axis is divided by 10. Therefore, 10 dB/DIV means 10 dB per each division. In this case, the full display range is 100 dB. If a marker is placed on a spectrum, the detailed data is shown regardless of level scale.