Patent ID: 7075475
Filing Date: 2006-07-11
Classification: H03M

Abstract:
1. A modulation system generating and receiving an analog input signal from an input sensor, said modulation system comprising: a switched excitation circuit coupled to excite said input sensor for generating an input voltage step; an integrator receiving said input voltage step through AC coupling and receiving a reference charge packet generated in response to a data dependent signal, said integrator integrating a charge indicative of the sum of an input charge associated with said input voltage step AC coupled to said integrator and said reference charge packet, said input charge and said reference charge packet having reverse polarities, and said integrator generating an integrator output signal; and a comparator having an input terminal coupled to receive a signal corresponding to said integrator output signal and comparing said integrator output signal to a reference level to generate a digital output signal at an output terminal, said data dependent signal having a value corresponding to said digital output signal, wherein said data dependent signal causes said reference charge packet to be generated synchronously with the excitation of said input sensor when said data dependent signal has a first value and causes no reference charge packet to be generated when said data dependent signal has a second value; and wherein said digital output signal forms a digital data stream over a plurality of sampling cycles, said digital data stream having an ones density proportional to a magnitude of said input voltage step.