A cerebral oximeter includes a first light source for emitting light in response to a first electrical signal, a second light source for emitting light in response to a second electrical signal, a first photodetector for detecting at least a portion of the light emitted from the first light source, and a second photodetector for detecting at least a portion of the light emitted from the second light source. The cerebral oximeter further includes a pseudonoise (PN) code modulator for modulating the first electrical signal and the second electrical signal using a spreading sequence to occupy an electrical bandwidth greater than necessary to send optical signal pulse amplitude information to a photodetector, and a time gate for filtering a first detection signal from the first photodetector and a second detection signal from the second photodetector based on a desired time-of-arrival.
