Noise considerations of optical beam recording.
This paper reviews the signal-to-noise considerations of optical beam reading processes. It shows that, with a binary light signal system using level detection, it is preferable to consider the arithmetic sum of the noise terms of each level as the noise term in a signal-to-noise calculation, even though the sum of the gaussian noise terms for each separate level are summed as powers. For the case where gaussian and nongaussian noise terms are combined for one level, it is preferable to add the peak values of their envelopes rather than employ rms values. The importance of the magnitude of the common mode rejection ratio, when deciding whether or not to employ a differential light detection system, is considered. The specific case of a magnetooptical material that exhibits Faraday rotation is used to illustrate these points in a quantitative fashion.
Beck
J W
JW