Patent ID: 7331235

Claim:
A device for indicating a beat level (L), the device comprising analyzer means (FT) which, in response to a reference frequency (Ω) and to a harmonic coefficient (B) extracts the following from an evaluation signal (E); a first acceleration signal (γ B ) at a frequency equal to the product of said reference frequency (Ω) multiplied by said harmonic coefficient (B); and a second acceleration signal (γ B-1 ) at a frequency equal to the product of said reference frequency (Ω) multiplied by said harmonic coefficient minus one; and the device further comprising a control circuit (CC) which receives said first and second acceleration signals (γ B , γ B-1 ) to produce said beat level (L), and wherein said beat level is equal to the ratio of the n th power of said second acceleration signal (γ B-1 ) divided by the first acceleration signal (γ B ).