A physiological measurement system can include a low noise patient cable that connects a monitor and a noninvasive optical sensor. A separation filter of the system models a downstream NOx estimated value of the catalyst with a value obtained by multiplying a coefficient by an output of an upstream-side NOx sensor. The representative process is executed on a source business process management platform and a target business process management platform. The slats may also be non-reflective or provided with a mirrored finish to effect control of light projection andor diffusion. An inner edge of the distal ring and the proximal ring are separated from the piston head of the piston so forming a first airway and a second airway.