A spectrophotometric instrument is comprised of a processor, a probe having a tissue engaging surface with an aperture therethrough and a light source producing measurement light signals and optically coupled to the probe via a first optical path. A partially reflective first reflecting member is located...http://www.google.es/patents/US7239385?utm_source=gb-gplus-sharePatente US7239385 - Method and apparatus for monitoring output signal instability in a light source
Method and apparatus for monitoring output signal instability in a light source
