Abstract: A method for learning a foreign language has a basic language kit including a sheet imprinted with a select list of key words in the foreign language, a workbook including a definition of each of the key words, and a recording of a correct pronunciation of each of the key words. Once the user has memorized the definition and the pronunciation of each of the key words, the sheet is used to facilitate a conversation between the user and a person fluent in the foreign language. Although the conversation is rudimentary at first, the user gains a working knowledge of the foreign language and learns proper sentence structure, grammar, and conjugation through repeated conversations.

Abstract: A digital audio reproduction system for compact discs, digital audio tapes and other similar systems suppresses digital noise present in the frequency band immediately above the audio band. Digital preprocessing combined with narrow output filters result in significant noise suppression without adverse distortion of the desired audio signal. The digital preprocessor may be combined with digital oversampling filters into a single integrated circuit or microprocessor.

Abstract: A stereo microphone that delivers "Right" and "Left" output signals from the sound field at a single point in space. A small, light, ball-like sound-sensing element is loosely suspended so that it is free to move in any direction in a plane. Directional components of its displacements are sensed and translated into electrical analog signals, which are then processed to provide separate stereo outputs. The sound-sensing element may be suspended on an optical fiber and its displacements sensed by a quad photodetector, whose four outputs are added and subtracted in certain combinations to derive the stereo outputs.

Abstract: A low-noise (low "rumble") segmented bearing for high-fidelity phonograph turntables and the like. In a preferred belt-driven form, the bearing consists of four small, spaced polyurethane pads disposed so that the tension of the belt keeps the shaft in contact with all of them. A fifth pad supports the end of the shaft. The bearing is immersed in lubricant.

Abstract: A tone arm for a phonograph pickup having a bifilar flexible ligament suspension for vertical and lateral displacement. The suspension takes the place of the more usual pivots, and employs a pair of thin flexible ligaments or fibers in a skewed convergent torsional bifilar configuration. The lower ends of the two ligaments are attached to a basal element, which may be shaped as a disc, connected to and lying below the arm itself. The flexibility of the ligaments confers freedom to the arm for angular displacement in the vertical and horizontal planes, but the skew prevents linear displacement along the direction of its length. The basal element is preferably immersed in a container of viscous liquid to damp movement of the arm.