Radiotelephone receiver and method with improved dynamic range and DC offset correction

An automatic gain control apparatus for a radiotelephone receiver comprising:

• memory containing data representing a transfer function of the radio telephone receiver;
• a gain estimation circuit, operatively coupled to the memory, that estimates input power and determines a required gain for an input signal based on a non-linear portion of the data representing the transfer function;
• and
• a DC offset compensation circuit operatively coupled to the gain estimation circuit, the DC offset compensation circuit comprising:
• a circuit for calculating a mean value of the signal having an in-phase (I) component and a quadrature (Q) component;
• an in-phase DC compensation circuit for calculating a DC offset error for the I component;
• a quadrature DC compensation circuit for calculating a DC offset error for the Q component, wherein the DC offset error for the I component and the DC offset error for the Q component are subtracted from the mean value of the signal;
• and
• a first analog to digital converter coupled to the circuit for calculating a mean value of the signal, wherein the first analog to digital converter receives the I component and produces a first digital I component containing 8 bits and a second digital I component containing 4 bits and wherein the 4 bits are a subset of the 8 bits.