Method and apparatus for digitally removing a DC-offset smaller than one LSB

A signal path, comprising:

• an analog to digital converter (ADC) for representing an input signal as n-bits, the n-bit representation comprising a DC offset component;
• a filter having an input coupled to an output of said ADC and an output for providing a filtered k-bit representation of said ADC output, where k=n+m, where m is a number of bits that represent a value smaller than one least significant bit (LSB) of said n-bit representation;
• and
• a summing node having a first input for inputting the k-bit output of said filter and a second input for inputting a k-bit representation of a DC offset component compensation value, wherein said summing node operates to subtract the value appearing at said second input from the value appearing at said first input, and to output a k-bit DC offset compensated value.

A method for removing a DC offset value in a signal path, comprising steps of:

• representing an input signal as n-bits, the n-bit representation comprising a DC offset component;
• subtracting from the n-bit representation a k-bit representation of a DC offset component compensation value, where k=n+m, where m is a number of bits that represent a value smaller than one least significant bit (LSB) of said n-bit representation;
• outputting a k-bit DC offset compensated value;
• and
• filtering the k-bit DC offset compensated value.

A method for removing a DC offset value in a signal path, comprising steps of:

• representing an input signal as n-bits, the n-bit representation comprising a DC offset component;
• filtering said n-bit representation to provide a filtered k-bit representation of said n-bit representation, where k=n+m, where m is a number of bits that represent a value smaller than one least significant bit (LSB) of said n-bit representation;
• and
• subtracting from the k-bit output of said filter a k-bit representation of a DC offset component compensation value for providing a k-bit DC offset compensated value.