Patent ID: 7003339
Filing Date: 2006-02-21
Classification: A61B,H04J

Abstract:
1. In a system that includes: a sampling frequency generator generating a sampling frequency f s ; a detector; a modulation signal generator, said modulation signal generator generating a sequence of pulses having a pulse repetition frequency, said pulses having a duty cycle of Q sample periods of said sampling frequency f s ; a transmitter which emits electromagnetic energy at a wavelength in response to said pulse, said detector receiving said electromagnetic energy to generate a detector output signal responsive to the received electromagnetic energy, said detector output signal including noise caused by ambient electromagnetic energy detected by said detector; a digital to analog converter which produces digital samples of said detector output signal at said sampling frequency; and a demodulator which demodulates said digital samples to produce a desired output signal, a method for minimizing said noise due to ambient electromagnetic energy in said desired output signal comprising the steps of: identifying all undesired frequency components of said ambient electromagnetic energy detected by said detector; using said undesired frequency components to compute a set of acceptable modulation cycle times T; and using said acceptable modulation cycle times to select said f