Patent ID: 8751171

Claim:
A method comprising: inducing motion in a conduit such that the conduit vibrates in a major mode of vibration having a major amplitude and a minor mode of vibration having a minor amplitude, wherein: the major amplitude is larger than the minor amplitude, and the major mode of vibration has a first frequency of vibration and the minor mode of vibration has a second frequency of vibration, accessing a first sensor signal from a first sensor configured to sense the motion of the conduit; accessing a second sensor signal from a second sensor configured to sense the motion of the conduit; determining a first amplitude of oscillation signal based on the first sensor signal; determining a second amplitude of oscillation signal based on the second sensor signal; determining a beat signal based on the first amplitude of oscillation signal and the second amplitude of oscillation signal; determining a frequency of the beat signal, wherein the frequency of the beat signal is related to the first frequency of vibration and the second frequency of vibration; and determining the second frequency of vibration based on the determined frequency of the beat signal.