Patent ID: 6225618
Filing Date: 2001-05-01
Classification: G01N,G03G

Abstract:
An auto-ranging densitometer for determining density of a test sample, the densitometer comprising:a photodetector that generates an electrical signal in response to incident light;an amplifier circuit adapted to receive the electrical signal and produce an output signal that is proportional to incident light intensity on the photodetector, the amplifier circuit having multiple gains that successively increase in an approximately 2:1 ratio increment;an analog to digital converter adapted to convert the output signal of the amplifier circuit into a series of digital signals; anda density signal generator circuit adapted to receive the series of digital signals and output a scaled density signal, wherein the density signal generator comprises a pair of look up tables with both the output of the analog to digital converter and the gain of the amplifier used as an addresses for the look up tables and the output from the look up tables is a concatenation of both outputs from the look up tables.