Patent ID: 7642766
Filing Date: 2010-01-05
Classification: G11C,H03K

Abstract:
1. A measurement method comprising emitting a light pulse form a light source and producing a measurement signal in a photodetector, said measurement signal having a variable reference level in the absence of the light pulse and a modified value during the light pulse, said method comprising the steps of performing, within a sample-and-hold circuit: a first correlated double sampling between a time T 1 situated just before the start of the measurement pulse and a time T 2 situated just before the end of the measurement pulse, this double sampling supplying a first value of said measurement signal considered with respect to a first value V 1 of said reference level before the start of the pulse; a second correlated double sampling between time T 2 and a time T 3 situated after the end of the measurement pulse, this second correlated double sampling supplying a second value of said measurement signal considered with respect to a second value V 3 of said reference level existing after the end of the pulse; and in establishing a difference between the first and second values of the measurement signals, this difference being a representation of the measurement signal considered with respect to an intermediate reference level that is comprised between the first and second values of the reference level.