Abstract: An oscillatory drive incorporating the invention includes a driven rotor that is mounted on a shaft and includes plural driven permanent magnets disposed thereon. A spring arrangement is coupled to the driven rotor and limits both clock-wise (CW) and counter-clockwise (CCW) rotation thereof. A first driving rotor includes first driving magnets, is mounted for rotation on the shaft and is positioned to a first side of the driven rotor. A second driving rotor includes second driving permanent magnets, is mounted for rotation on the shaft and is positioned to a second side of the driven rotor. The drive mechanism imparts a CW rotation to the first driving rotor and a CCW rotation to the second driving rotor. The first driving permanent magnets coupling to the driven permanent magnets causes a CW rotation of the driven rotor until the spring arrangement terminates the CW rotation and causes a reversal of rotation direction in the CCW direction.

Abstract: A method and apparatus are described for holographically generating visual representations of acoustical characteristics of sound sources. A planar array has a lattice of microphone receiving points are disposed such that evanescent wave energy from the sources is detected along with propagating wave energy. The microphone outputs are sampled, resolved into phase and amplitude components, digitized and subjected to fast Fourier transform operations to provide computer graphic display means with holographic reconstruction parameters corresponding to the sources under analysis.