Question

What is the principle behind Doppler velocimetry working?

(a) amplitude measurement of fiber optic sensor

(b) frequency measurement of fiber optic sensor

(c) time shift measurement of fiber optic sensor

(d) phase measurement of fiber optic sensor

I got this question in semester exam.

This intriguing question originated from Transmission of Analog Physiological Signals Over Telephone in portion Biomedical Telemetry of Biomedical Instrumentation

Answer 1

The correct choice is (b) frequency measurement of fiber optic sensor

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