Patent ID: 7583384
Filing Date: 2009-09-01
Classification: G01C

Abstract:
1. A system for driving a sensing coil, the circuit comprising: a photodetection circuit having an input for receiving an optical output from the sensing coil and having an output, said photodetection system producing a digital signal from said optical output; a signal processing circuit having an input coupled to said output of said photodetection circuit and having an output for supplying an output signal to modulate said sensing coil, said signal processing circuit configured to produce a feedback signal from said digital signal and further configured to add a random number to said feedback signal to produce said output signal; a digital-to-analog converter (DAC) having an input for receiving said output signal and having an output; and an amplifier having an input coupled to said output of said DAC and having an output for coupling with said sensing coil, wherein said DAC has a first resolution, wherein said signal processing circuit has a second resolution greater than said first resolution, and wherein said random number has a size corresponding to a difference between said second resolution and said first resolution.