Methods and systems for using an estimate signal to improve signal resolution in a physiological monitor

A system for processing a sensor signal in a physiological monitor, the system comprising:

• processing equipment configured to perform operations comprising:
• receiving an analog sensor signal corresponding to an intensity of detected light attenuated by a subject, wherein the analog sensor signal comprises at least a first segment corresponding to an ambient light interval and a second segment correspond to an emitted light interval;
• generating an analog estimate signal, wherein the analog estimate signal comprises an estimate corresponding to at least a portion of the first segment and an estimate corresponding to at least a portion of the second segment;
• generating an analog difference signal based at least in part on the analog sensor signal and the analog estimate signal;
• and
• determining a physiological parameter of the subject based at least in part on the analog difference signal.

A method for determining a physiological parameter of a subject, comprising:

• receiving, using processing equipment, a signal representing intensity of light attenuated by a subject;
• generating, using the processing equipment, an estimate signal based at least in part on an idealized light intensity signal;
• generating, using the processing equipment, a difference signal representing a difference between the received signal and the estimate signal;
• amplifying, using the processing equipment, the difference signal;
• and
• determining, using the processing equipment, a physiological parameter of the subject based at least in part on the amplified difference signal.