Calibrating a phase detector and analog-to-digital converter offset and gain

An apparatus comprising:

• a phase detector to generate a phase detector pulse;
• an analog-to-digital converter (ADC) coupled to receive the phase detector pulse;
• a calibration loop coupled to receive an output of the ADC and to generate a phase adjust value to force an average value of the ADC output to be substantially zero;
• and
• storage to store the phase adjust value.

A system comprising:

• an amplifier to receive optical energy and convert the optical energy to electrical energy;
• a phase detector coupled to the amplifier to generate a phase detector pulse, and to develop an error pulse and a reference pulse to combine into the phase detector pulse;
• an analog-to-digital converter (ADC) coupled to receive the phase detector pulse;
• and
• a calibration loop coupled to receive an output of the ADC and to generate a phase adjust value to force a filtered value of the ADC output to be substantially zero.

An apparatus comprising:

• a phase detector to receive incoming data and to output the incoming data and a phase detector pulse, and including a multiplier to combine a phase adjust value with an error pulse;
• an analog-to-digital converter (ADC) coupled to receive the phase detector pulse;
• and
• a calibration circuit coupled to receive an output of the ADC and to generate the phase adjust value to force an average value of the ADC output to be substantially zero.