Fully digital AGC circuit with wide dynamic range and method of operation

A wireless network comprising:

• a plurality of base stations capable of communicating with mobile stations located in a coverage area of said wireless network, wherein at least one of said base stations comprises a radio frequency receiver controlled by a digital automatic gain control (AGC) circuit comprising:
• a first shifter capable of receiving an in-phase signal as a first series of X-bit samples and left-shifting each X-bit sample by a number of bits determined by a coarse scaling factor;
• a first limiter capable of receiving the D most significant bits of the output of the first shifter and outputting a subset of the D most significant bits of the first shifter output;
• a first multiplier capable of multiplying the subset of the D most significant bits of the first shifter output by a fine scaling factor to produce a first M-bit product;
• and
• a gain adjustment circuit capable of comparing a power signal derived from said first M-bit product to a maximum threshold value and generating said coarse scaling factor and said fine scaling factor.

For use in a radio frequency (RF) receiver, a method of performing gain control in a digital automatic gain control (AGC) circuit comprising:

• receiving in a first shifter an in-phase signal as a first series of X-bit samples and left-shifting each X-bit sample by a number of bits determined by a coarse scaling factor;
• receiving in a first limiter the D most significant bits of the output of the first shifter and outputting a subset of the D most significant bits of the first shifter output;
• multiplying in a first multiplier the subset of the D most significant bits of the first shifter output by a fine scaling factor to produce a first M-bit product;
• and
• comparing a power signal derived from the first M-bit product to a maximum threshold value and generating the coarse scaling factor and the fine scaling factor.