Abstract: An interactive keyboard and display apparatus is used to enter ideographic characters in a computer or other utilisation device. The characters are defined by manually selecting displayed symbols such as phonemes, strokes, radicals and inflective tones represented in displayed key cells which are arranged in a matrix for rapid selection. Simultaneous multiple key cell selection is possible for accelerated character entry. The keyboard and display are integrated in a format suitable for replacing conventional keyboards. To avoid spurious entries, a pre-determined amount of pressure must be applied to the display panel when entering a symbol or character.

Abstract: A swimming pool producing surrounding visual effects utilizes large picture generating surfaces adjacent to water-containing surfaces for displaying large images emulative of remote swimming environments. The pool has controllable water currents for in-place swimming or diving in one or more directions. These controlled water currents and the large images are coordinated by a computer for producing a virtual underwater environment in which picture scenes evolve and water-currents flow as a function of swimmer activity. A large apparent swimming area can therefore be produced. For added realism, the pool may include sound-generating devices and parametric weather machines to accurately emulate natural environments and also produce spectacular special effects for the swimming or diving subject and for possible observers thereof.

Abstract: An elastic pickup saddle for the bridge of a stringed musical instrument uses the anti-nodal area of a flexible elastic member therein to support an elastic vibratable string. The elastic member may be a beam, a span, a plate, a diaphragm, or a composite structure acting mechanically in a similar manner. The loaded anti-nodal area of the elastic member flexes between at least two nodal points of support. The elastic member is pre-stressed and deformed by a relatively static string pressure proportional to the string's tension. When string and/or body vibrations modulate this relatively static pressure, the pre-stressed elastic member interacts mechanically with the string, thus disturbing those vibrations. A piezoelectric strain sensor monitors the flexions of the elastic member and produces an enriched tone signal in response to the disturbed string and/or body vibrations. The flexible member is supported by a massive element typically including the bridge and a portion of the instrument body.

Abstract: A pickup responsive in all planes of vibration of a vibrating element of a musical instrument uses two transducers, each maximally responsive in a different plane of vibration. The transducer signals are dephased with respect to each other in order to reduce and possibly eliminate the additive and substractive tendencies of the common portion of the signals when they are combined to produce the pickup signal. The signals may be dephased using a phase shifting network or device, or by using different types of transducers (i.e.: position-sensing for the first transducer and velocity-sensing for the second transducer) which produce signals which are already dephased and thus only require to be combined in order to produce the claimed response.

Abstract: A noise-cancelling pickup for a stringed instrument uses two transducers to monitor different forces exerted by a vibratable string under tension. The first transducer is responsive to the music vibrations of the vibrating portion of the string but it is also responsive to variations of the string tension which are not related to the music vibrations of the string. The second transducer is mainly subjected to the variations of the string tension which are not related to the desirable music vibrations. The signals from the transducers are combined in and out-of-phase manner to produce a joint signal in which the spurious components corresponding to the variations of the string tension are significantly attenuated and possibly eliminated.

Abstract: A pickup for a string under tension of a musical instrument having an improved planar response uses a pair of mechanically independent pressure transducers preferably adjacent to one another which provide independent support to transversely adjacent points of the string. The independent transducers allow the string to roll slightly on one transducer when applying pressure to the other as a result of the string vibration, thus increasing the sensitivity of the pickup in planes near the plane of minimum sensitivity. The transducers may rest on a common massive element which is resiliently coupled to the bridge of the instrument. The transducers preferably have rounded string-contacting surfaces in order to reduce the magnitude of the shear forces exerted on the pickup when the string tension is varied.

Abstract: The tone signal from a transducer monitoring the music vibrations of a bowed musical instrument contains an objectionable friction noise component which is removed by passing the tone signal through a high-pass filter having a variable cutoff frequency which is controlled by a pitch detector monitoring the fundamental frequency of a played note in the tone signal. The cutoff frequency of the filter is kept slightly below the fundamental frequency of the played note to avoid altering the tone color of the tone signal. When no fundamental frequency is detected by the pitch detector, the cutoff frequency of the filter remains at a pre-determined minimum which may be adjustable by the musician for best effect when strings are both bowed and plucked. The filtered tone signal may be applied to the pitch detector in order to increase the accuracy of the pitch detection process and thus increase the accuracy of the noise reducing characteristics of the system.

Abstract: An apparatus for producing a signal indicative of the direction of bowing of a musical instrument by analyzing the signal from a transducer monitoring the displacements of a bowed vibrating element in the plane of bowing. The indicative signal is stored for the entire duration of a played note or musical passage.

Abstract: A device to produce sub-harmonic tone signals in response to a tone signal from a transducer having preferably maximum sensitivity in the plane of bowing of a bowed musical instrument by passing selected cycles of the transducer signal through signal gates which are controlled jointly by sub-harmonic control signals at sub-multiples of the fundamental frequency of the transducer signal and by a signal indicative of the detection of a fundamental frequency. Each sub-harmonic tone signal thus produced has a tone color which approximates that of the corresponding bowed musical instrument of the same frequency range and which is independent of the direction of bowing.