Systems and Methods for Semi-Independent Loop Processing

A data processing circuit, the data processing circuit comprising:

• a variable gain amplifier circuit operable to amplify an analog input and to provide a data input;
• an analog to digital converter circuit operable to receive a data input and to provide corresponding digital samples;
• a digital filter circuit operable to receive the digital samples and to provide a filtered output;
• a data detector circuit operable to perform a data detection process on the filtered output to yield a detected output;
• a mimic filter circuit operable to receive the digital samples and to provide a mimicked output;
• and
• an automatic gain control loop circuit operable to provide a gain control feedback based at least in part on the mimicked output and a derivative of the detected output, and wherein the gain control feedback at least in part controls the amplification applied by the variable gain amplifier circuit.

A method for data processing, the method comprising:

• performing a variable gain amplification on an analog input using a variable gain amplifier circuit to yield an analog output, wherein a magnitude of the variable gain amplification is controlled at least in part by an analog feedback signal;
• performing an analog to digital conversion on the analog output to yield a series of digital samples, wherein each of the series of digital samples is synchronous to a sample clock;
• performing a digital filtering of the digital samples using a digital filter circuit to yield a filtered output, wherein the digital filtering is at least in part controlled by a filter feedback;
• performing a data detection process on the filtered output to yield a detected output;
• performing a mimicked filtering of the digital samples to yield a mimicked output;
• generating the filter feedback to the digital filter circuit based at least in part on a derivative of the detected output;
• generating the analog feedback signal to the variable gain amplifier circuit based at least in part on a combination of the mimicked output and a derivative of the detected output;
• and
• generating the sample clock based at least in part on a combination of the mimicked output and a derivative of the detected output.