Pulse oximeter with improved accuracy and response time Patent #: 5190038
ApplicationNo. 932747 filed on 09/17/1997
US Classes:600/336Detects constituents while excluding components (e.g., noise)
ExaminersPrimary: Hindenburg, Max
Assistant: Winakur, Eric F.
Attorney, Agent or Firm
International ClassA61B 005/00
AbstractThe present invention provides a method and apparatus for adapting to noise sources affecting a pulse oximeter. Various available frequencies are evaluated to determine their respective noise levels and one is selected to act as the operating demultiplexer frequency. During normal operation of the pulse oximeter, the various available demultiplexer frequencies are periodically scanned to determine which has the lowest associated noise. The noise level associated with the operating frequency is used to determine the signal-to-noise ratio of the pulse oximeter signals and thereby qualify certain signals from the pulse oximeter. Those pulses associated with a signal-to-noise ratio below a predetermined threshold are rejected and excluded from use in calculating blood oxygen saturation.