Method and apparatus for a router line card with adaptive selectable gain control

A computer readable medium containing program instructions for calibrating a line card having a gain control circuit, an adjustment control circuit, a comparator, and memory device, the gain control circuit being configured to receive an input signal and an adjustment signal and to output an adjusted output signal that is based on the input signal and the adjustment signal, the comparator being configured to compare the input signal to a nominal amplitude value and to output a comparison signal that indicates whether the input signal requires an adjustment, the adjustment control circuit being configured to alter the adjustment signal to a nominal adjustment value so that an adjusted amplitude value of the adjusted signal converges with the nominal amplitude value when the comparison signal indicates that the input signal requires adjustment, the computer readable medium comprising:

• computer readable code for providing a first input signal and a first adjustment signal to the gain control circuit so that the gain control circuit outputs an adjusted output signal;
• computer readable code for providing a nominal amplitude value to the comparator so that the comparator outputs a first comparison signal that indicates whether the first input signal requires an adjustment;
• computer readable code for determining a first nominal adjustment value based on the first comparison signal;
• computer readable code for substantially permanently storing the first nominal adjustment value within a first address of the memory device, the first address being associated with the first input signal;
• and
• a computer readable medium that stores the computer codes.

A computer system for calibrating a line card having a gain control circuit, an adjustment control circuit, a comparator, and memory device, the gain control circuit being configured to receive an input signal and an adjustment signal and to output an adjusted output signal that is based on the input signal and the adjustment signal, the comparator being configured to compare the input signal to a nominal amplitude value and to output a comparison signal that indicates whether the input signal requires an adjustment, the adjustment control circuit being configured to alter the adjustment signal to a nominal adjustment value so that an adjusted amplitude value of the adjusted signal converges with the nominal amplitude value when the comparison signal indicates that the input signal requires adjustment, the computer system comprising:

• an initializer mechanism arranged to provide a first input signal and a first adjustment signal to the gain control circuit and a nominal amplitude value to the comparator so that the comparator outputs a comparison signal that indicates whether the first input signal requires an adjustment;
• and
• a determination mechanism arranged to determine a first nominal adjustment value based on the comparison signal and to substantially permanently store the first nominal adjustment value within a first address of the memory device, the first address being associated with the first input signal.

A computer readable medium containing program instructions for calibrating a line card having a gain control circuit and memory device, the gain control circuit being configured to receive an input signal and an adjustment signal and to output an adjusted output signal that is based on the input signal and the adjustment signal, the memory device having a plurality of nominal adjustment values that are each associated with a particular input signal, the computer readable medium comprising:

• computer readable code for retrieving a first nominal adjustment value that is associated with a first input signal the memory device;
• computer readable code for providing a first adjustment signal to the gain control circuit based on the first nominal adjustment value;
• and
• a computer readable medium that stores the computer codes.