Doppler velocimetry works on the principle of __________ A. frequency

doppler-velocimetry-works-on-the-principle-of-a-frequency

Doppler velocimetry works on the principle of __________

A. frequency measurement of fiber optic sensor

B. amplitude measurement of fiber optic sensor

C. phase measurement of fiber optic sensor

D. time shift measurement of fiber optic sensor

I got this question during an online exam.

Origin of the question is Biosensors topic in portion Physiological Transducers of Biomedical Instrumentation

Correct choice is A. frequency measurement of fiber optic sensor

The explanation: Doppler velocimetry works on the principle of frequency measurement of fiber optic sensor. In this method, light from a laser, normally helium/neon, is sent via a fibre onto the skin surface. The moving red blood cells scatter the light and produce a Doppler frequency shift because of their movement.