Method and apparatus to independently control front end gain and baseband gain

A method for automatic gain control in a receiver, comprising:

• in a first comparison, comparing a first energy level of an input signal to a front-end threshold;
• in a second comparison, comparing a second energy level of a digital representation of the input signal to saturation thresholds of an analog-to-digital converter in the receiver, wherein the second comparison includes at least two sub-comparisons, a first sub-comparison using a low saturation threshold and a second sub-comparison using a high saturation threshold, wherein the first comparison has a wider bandwidth than the second comparison;
• and
• adjusting gain levels independently at a front-end of the receiver and a baseband-end of the receiver based on the first and second comparisons,
• wherein the baseband gain level is reduced via a larger step size if the second energy level is above the high saturation threshold than if the second energy level is above the low saturation threshold but below the high saturation threshold.

An automatic gain control circuit, comprising:

• a peak detector input;
• a saturation detector input;
• a non-volatile memory storing a first LUT with front-end gain settings and a second LUT with baseband gain settings, wherein the first LUT includes two sets of front-end gain settings, a first set for a first front-end gain element and a second set for a second front-end gain element;
• a controller to generate a front end gain value and a baseband gain value based on the peak detector input and saturation detector input using the first and second LUTs, wherein the saturation detector input includes information about a saturation level of an analog-to-digital converter based on a low saturation threshold and a high saturation threshold;
• a first output to transmit the front end gain value;
• and
• a second output to transmit the baseband gain value.