MULTIPLE BIT SIGMA-DELTA MODULATOR WITH A COMMON MODE COMPENSATED QUANTIZER

摘要

A quantizer for an analog to digital converter has an input for receiving an analog input signal. A detector senses a common mode voltage component of the input signal. A reference voltage source produces a plurality of reference voltages. A voltage source biases the reference voltage source in response to the sensed common mode voltage component. Therefore, the common mode voltage in the input signal establishes the common mode voltage of the reference voltage source. A plurality of comparators are connected to the reference voltage source, wherein each of the plurality of comparators compares the input signal to one of the plurality of reference voltages and produces a output bit denoting a result of the comparing.

主权项

1. A method for converting an analog input signal into multiple digital bits using a quantizer, said method comprising:
detecting a common mode voltage of the analog input signal; providing a reference voltage source for producing a plurality of reference voltages; biasing the reference voltage source in response to the common mode voltage; andperforming a plurality of comparisons of the analog input signal to each of the plurality of reference voltages, wherein each comparison produces a quantizer output bit.