Versatile resonance-tracking circuit for acoustic levitation experiments.
Objects can be levitated by radiation pressure forces in an acoustic standing wave. In many circumstances it is important that the standing wave frequency remain locked on an acoustic resonance despite small changes in the resonance frequency. A self-locking oscillator circuit is described which tracks the resonance frequency by sensing the magnitude of the transducer current. The tracking principle could be applied to other resonant systems.
Baxter
K
K
Department of Engineering and Applied Science, Yale University, New Haven, Connecticut 06520.
Apfel
R E
RE
Marston
P L
PL