Abstract: A waveguide system for radiating sound waves. The system includes a low loss waveguide for transmitting sound waves, having walls are tapered so that said cross-sectional area of the exit end is less than the cross-sectional area of the inlet end. In a second aspect of the invention, a waveguide for radiating sound waves, has segments of length approximately equal to A ? ( y ) = A inlet ? [ 1 - 2 ? Y B + ( y B ) 2 ] where l is the effective length of said waveguide and n is a positive integer. The product of a first set of alternating segments is greater than the product of a second set of alternating segments, in one embodiment, by a factor of three. In a third aspect of the invention, the first two aspects are combined.

Abstract: An induction cooking utensil is constructed such that it cooks food within its chamber while maintaining a relatively cool outer surface (e.g., preferably an outer surface that is cool enough to pick up with one's bare hands). The cooking utensil includes an inner wall that is made at least in part of an electrically conductive material and an outer wall that is made at least in part of the electrically non-conductive material. A reflective layer is disposed between the inner and outer walls to reflect radiant heat away from the outer wall.

Abstract: An induction cooking utensil is constructed to have an inner wall that is made at least in part of electrically conductive material and an outer wall having a bottom portion and a sidewall portion. The bottom portion is made at least in part of a non-conductive material (e.g., so as to not interfere substantially with the magnetic field produced by the induction cooktop) and the sidewall portion is made at least in part of a metallic material.

Abstract: An induction cooking utensil is constructed such that it cooks food within its chamber while maintaining a relatively cool outer surface (e.g., preferably an outer surface that is cool enough to pick up with one's bare hands). The cooking utensil includes an inner wall that is made at least in part of an electrically conductive material and an outer wall that is made at least in part of the electrically non-conductive material. A reflective layer, a vacuum-sealed thermal insulator and/or a gas more resistant to conducting heat than air is disposed between the inner and outer walls to resist the transfer of heat from the inner wall to the outer wall.

Abstract: An induction cooking utensil includes an inner wall and an outer wall that is separated by a vacuumed-gap. Disposed within the vacuumed-gap is a piece of getter material that absorbs at least some gas present within the gap. The getter material may thus be used to create and/or preserve the vacuum.

Abstract: An audio system including an audio power amplifier, a transducer electrically connected to the audio power amplifier, an enclosure coupled to the transducer, and a secondary resonant element coupled to the enclosure. An electrical feedback signal representative of the transducer current is negatively fed back to the audio power amplifier to synthesize a positive output impedance.

Abstract: An electromagnetic actuator includes a stator assembly mounted to a center pole formed of material having high magnetic permeability and functions as a return path for the magnetic field generated when current is passed through coils in the stator assembly. When current is applied to one or more coils within the stator assembly, a magnetic field is generated that interacts with a magnetic field generated by one or more magnets disposed within the armature assembly and causes the armature to move relative to the center pole thus, for example, opening or closing a valve.

Abstract: An electromagnetic actuator includes a stator assembly mounted to a center pole formed of material having high magnetic permeability and functions as a return path for the magnetic field generated when current is passed through coils in the stator assembly. When current is applied to one or more coils within the stator assembly, a magnetic field is generated that interacts with a magnetic field generated by one or more magnets disposed within the armature assembly and causes the armature to move relative to the center pole thus, for example, opening or closing a valve.

Abstract: An electromagnetic actuator includes a stator assembly mounted to a center pole formed of material having high magnetic permeability and functions as a return path for the magnetic field generated when current is passed through coils in the stator assembly. When current is applied to one or more coils within the stator assembly, a magnetic field is generated that interacts with a magnetic field generated by one or more magnets disposed within the armature assembly and causes the armature to move relative to the center pole thus, for example, opening or closing a valve.

Abstract: An electromagnetic actuator includes a stator assembly mounted to a center pole formed of material having high magnetic permeability and functions as a return path for the magnetic field generated when current is passed through coils in the stator assembly. When current is applied to one or more coils within the stator assembly, a magnetic field is generated that interacts with a magnetic field generated by one or more magnets disposed within the armature assembly and causes the armature to move relative to the center pole thus, for example, opening or closing a valve.

Abstract: A waveguide system for radiating sound waves. The system includes a low loss waveguide for transmitting sound waves, having walls are tapered so that said cross-sectional area of the exit end is less than the cross-sectional area of the inlet end. In a second aspect of the invention, a waveguide for radiating sound waves, has segments of length approximately equal to A ? ( y ) = A inlet ? [ 1 - 2 ? Y B + ( y B ) 2 ] where l is the effective length of said waveguide and n is a positive integer. The product of a first set of alternating segments is greater than the product of a second set of alternating segments, in one embodiment, by a factor of three. In a third aspect of the invention, the first two aspects are combined.

Abstract: A waveguide system for radiating sound waves. The system includes a low loss waveguide for transmitting sound waves, having walls are tapered so that said crosssectional area of the exit end is less than the cross-sectional area of the inlet end. In a second aspect of the invention, a waveguide for radiating sound waves, has segments of length approximately equal to A ⁡ ( y ) = A inlet ⁡ [ 1 - 2 ⁢ Y B + ( Y B ) 2 ] where l is the effective length of said waveguide and n is a positive integer.

Abstract: An electromagnetic transducer includes a first member and a second member which are relatively slidable along a path having spaced endpoints and which are electromagnetically coupled. The second member has at least one winding which produces a magnetic field which penetrates the second member. The second member has a plurality of contiguous permanent magnets of alternate polarity along the path which establish a periodic magnetic field which reacts with the magnet field created by the first member so as to produce force along the path. The plurality of contiguous permanent magnets are disposed along the path such that transition lines dividing adjacent ones of the magnets are formed at a non-perpendicular angle to the path to allow gradual transition between flux directions.

Abstract: A digital absolute position encoder is provided for determining absolute position of a first member with respect to a second member. The absolute position is determined within a resolution cell of L/2.sup.n, where n is an integer and L is a predetermined span. One of the members has a plurality of, m, tracks of binary indicia distributed over the predetermined span, L, where m is an integer less than n. The other member has a plurality of indicia detectors disposed on the second member for detecting the binary indicia. With such an arrangement, an encoder is provided having "a unit-distance code", yet uses less tracks than that used with a conventional Gray code encoder. Further, the encoder has a reduced number of transitions than that required on the track used with a conventional Gray code encoder. Both of these features simplify the design and fabrication for a given encoder resolution.

Abstract: A two-state modulation system includes a hysteretic comparator with variable thresholds, a two-state processor and an integrating element. A summing circuit combines a signal coupled from the output of the two-state processor, the signal output, the signal input and a delay compensating signal feedback input and a feedback input from an integrating element at the output of the two-state processor. The hysteretic comparator receives a hysteresis control signal that varies the threshold. The hysteresis control signal may be provided by analog switches switched by the switching signal to provide the switched two-state levels to a low pass filter. Rectifying circuitry may also be used for supplying the hysteresis control signal. Limiters and compressors may be connected to the input with the limiter limiting levels tracking the two-state levels, and the compression proportional to the switching frequency.

Abstract: A transducer includes a core of low reluctance magnetic material formed with a narrow gap. There are first and second coils of conductive material wound on the core adjacent to and on opposite sides of the gap. A permanent magnet in and substantially filling the gap is in noncontacting relationship with the core and supported to allow relative movement between the permanent magnet and the core. The core may be generally U-shaped, C-shaped or 8-shaped with the path of relative movement between the permanent magnet and the core usually generally perpendicular to the plane of the core. No portion of the core is in the plane of permanent magnet movement. The permanent magnet preferably comprises first and second contiguous permanent magnet elements having adjacent unlike poles along a boundary substantially midway between opposed surfaces of the core along the direction of relative motion.

Abstract: A loudspeaker system has an enclosure with a baffle dividing the interior into first and second subchambers. The smaller subchamber is directly coupled to the region outside the enclosure by a port tube. The larger subchamber is coupled to the region outside the enclosure via the smaller subchamber by a port tube. The dividing baffle carries a woofer.

Abstract: In a vehicle having a chassis and at least one wheel assembly, where the wheel assembly includes a wheel support member, a damping mass, a damping spring for connecting the damping mass to the wheel support member, and a mechanical resistive member in parallel with the damping spring, a suspension connecting the wheel assembly to the chassis, the suspension supporting the weight of the vehicle and isolating the wheel motion from the chassis motion, and at least one actuator for providing force between the wheel assembly and the chassis, the improvement provides a linear electric motor connected between the wheel assembly and the chassis, where the linear electric motor provides force between the wheel assembly and the chassis.

Abstract: In a current controlled two-state modulation system having a power switch and a low pass filter, a current sensor provides a current feedback signal representative of the current delivered by the power switch to the low pass filter. The low pass filter also provides a voltage feedback signal that is combined with a reference signal to provide a combined signal. A limiting amplifier amplifies the combined signal for further combination with the current feedback signal to provide a switching signal that is delivered to a circuit characterized by hysteresis. This circuit determines the instant when the power switch is switched so as to maintain the output voltage provided by the low pass filter substantially constant so long as the load current is less than a predetermined limiting value determined by the limiting amplifier and thereafter limits the output current to substantially the predetermined limiting value.

Abstract: A multiple driver loudspeaker system comprises two angularly spaced rear rectangular baffles each nearly filled with four closely spaced full-range small loudspeakers with a port tube passing through the center of each rear baffle and the junction therebetween. A front baffle carries a small centrally located loudspeaker. The front loudspeaker is backed by a cavity that is vented through the port tube at the intersection between the rear baffles. Each of the remaining loudspeakers is backed by a cavity with the four cavities associated with each rear baffle being vented through the associated port tube through channels located at the front of each cavity. Two bullets are cantilevered from the front baffle rearward and essentially concentric within the respective centrally located ports. The volume of each of the nine cavities is substantially the same.