Rotational speed sensor with transmitter and two receivers

摘要

The sensor includes a metallic interdigital structure (2) arranged on a planar piezoelectric layer (1). The structure is supplied with a periodic electrical signal and acts as a transmitting transducer for an acoustic wave propagated at right angles to it. Two receiving transducers on the same piezoelectric layer have similar interdigital structures (3,4) which convert the acoustic wave into amplitude-modulated electrical signals. The difference between these is proportional to the angular velocity of the substrate (5) on which the appts. is mounted.