Patent ID: 7554072

Claim:
A photodiode amplifier comprising: an amplifier having an amplifier inverting input, an amplifier non-inverting input, and an amplifier output; a photodiode having a photodiode anode electrically connected with the amplifier inverting input and a photodiode cathode electrically connected with the amplifier non-inverting input; a fixed voltage reference electrically connected with the photodiode cathode and the amplifier non-inverting input via a low pass filter; a gain resistor coupling the amplifier inverting input with the amplifier output wherein a value of the gain resistance is at least doubled by multiplying at least twice a reference voltage and dividing it by a diode current, which establishes a voltage gain which is substantially equal to a low limit of an amplification of the amplifier; and an analog to digital converter coupled to the amplifier output noise floor effects of the analog to digital converter accounted for via measuring a noise floor of the analog to digital converter by shorting inputs of the analog to digital converter.