Abstract: Provided are apparatuses and methods for reducing nonlinear distortions in Class D amplifiers by dynamically changing first and second threshold voltages in a pulse width modulator. A Class D amplifier apparatus is disclosed, comprising a pulse width modulator whose operation relies on a first and second threshold value, and a threshold controller which varies the thresholds in response to internal signals in the amplifier. Further, a method of processing Class D amplifier internal signals is disclosed, comprising steps involving measuring internal signals in a Class D amplifier and varying threshold signals in response to those measurements within the amplifier.

Abstract: Provided are apparatuses and methods for reducing nonlinear distortions in Class D amplifiers by dynamically changing first and second threshold voltages in a pulse width modulator. A Class D amplifier apparatus is disclosed, comprising a pulse width modulator whose operation relies on a first and second threshold value, and a threshold controller which varies the thresholds in response to internal signals in the amplifier. Further, a method of processing Class D amplifier internal signals is disclosed, comprising steps involving measuring internal signals in a Class D amplifier and varying threshold signals in response to those measurements within the amplifier.

Abstract: A method for identifying and recording the relative positions of loudspeakers in an array with respect to one another using amplifiers connected on a network.

Abstract: There is provided a device for propagating acoustic vibrations through an environment. The device includes a low pressure chamber containing a volume of reduced pressure relative to the environment. A movable wall is formed on the low pressure chamber, said movable wall having an ambient side facing the environment and a low pressure side facing the volume of reduced pressure. The movable wall is sufficiently biased towards the environment and away from the volume of reduced pressure such that the movable wall can freely vibrate back and forth relative to the volume of reduced pressure in response to acoustic vibrations impinging on the ambient side of the movable wall. The device has the acoustical compliance of a device of far larger volume.

Abstract: A double-sided, indexable face milling insert, including an upperside, an underside, and a neutral plane (NP) parallel to the upperside and the underside, the neutral plane forming a right angle with a geometrical center axis (C2). A plurality of indexable cutting edges are formed along circumferential borderlines in transitions between a number of clearance surfaces and the upperside as well as the underside. Each cutting edge includes a chip-removing main edge and a surface-wiping secondary edge, the secondary edge forming an obtuse angle with the main edge in plane view. A corner clearance surface extends between and connects each pair of upper and lower secondary edges, the corner clearance surface including first and second part surfaces which each form an acute angle (?) in side elevation view with respective reference planes (RP) parallel to the neutral plane.

Abstract: A milling insert, including an upperside, an underside, and a reference plane parallel to the upperside and the underside. A plurality of indexable cutting edges are formed along a peripheral borderline in transitions between at least the upperside and a number of clearance surfaces. Each cutting edge includes a chip-removing main edge and a surface-wiping secondary edge, the secondary edge forming an obtuse angle with the main edge as viewed in planar view from the upperside. The main edge, from a first end of the main edge adjacent to the secondary edge, first declines toward the underside of the milling insert and then, from a lowest part, rises toward an opposite second end of the main edge. The secondary edge is inclined at an angle (?) in relation to the reference plane as viewed perpendicularly to the clearance surface of the secondary edge, such that a first end of the secondary edge connected to the main edge is situated on a lower level than the opposite, second end of the secondary edge.

Abstract: A drilling tool set includes a plurality of drilling tools having different operative drill diameters to blast drill holes of different respective diameters. Each drilling tool of the set has a basic body defining a central axis of rotation, and two replaceable indexable bits including a center bit and a periphery bit which are mountable in respective center and periphery pockets formed in a front end of the basic body. The periphery bits of the respective drill tools of the set are identical, and the center bits of the respective drill tools of the set are identical. Each of the center and periphery pockets of each drill tool defines a radial center point. A first of the drill tools has a smaller operative drill diameter than a second of the drill tools. The first tool includes a first periphery pocket and a center pocket. The center point of the first periphery pocket is disposed closer to the axis than is the center point of the second periphery pocket.

Abstract: A drilling tool includes a basic body defining a center axis of rotation and having two chip channels and two replaceable indexable cutting bits in the form of a center bit and a periphery bit mounted in respective center and periphery pockets formed in an axially front end of the basic body. The center bit and the center pocket are spaced radially from the periphery bit and the periphery pocket along a first diametrical plane of the basic body. At least the center bit includes four identically-shaped cutting edges, one of which constituting an operative cutting edge intersected by a second diametrical plane oriented perpendicularly to the first diametrical plane. Each cutting edge of the center bit comprises first and second part edges joined by a transition edge portion.

Abstract: A drilling tool includes a basic body defining a center axis of rotation and having two chip channels and two replaceable indexable cutting bits in the form of a center bit and a periphery bit mounted in respective center and periphery pockets formed in an axially front end of the basic body. The center bit and the center pocket are spaced radially from the periphery bit and the periphery pocket along a first diametrical plane of the basic body. At least the center bit includes four identically-shaped cutting edges, one of which constituting an operative cutting edge intersected by a second diametrical plane oriented perpendicularly to the first diametrical plane. Each cutting edge of the center bit comprises first and second part edges joined by a transition edge portion.

Abstract: A drilling tool set includes a plurality of drilling tools having different operative drill diameters to blast drill holes of different respective diameters. Each drilling tool of the set has a basic body defining a central axis of rotation, and two replaceable indexable bits including a center bit and a periphery bit which are mountable in respective center and periphery pockets formed in a front end of the basic body. The periphery bits of the respective drill tools of the set are identical, and the center bits of the respective drill tools of the set are identical. Each of the center and periphery pockets of each drill tool defines a radial center point. A first of the drill tools has a smaller operative drill diameter than a second of the drill tools. The first tool includes a first periphery pocket and a center pocket. The center point of the first periphery pocket is disposed closer to the axis than is the center point of the second periphery pocket.

Abstract: An indexable cutting insert for metal machining comprises an upper rake surface, a bottom surface and side surfaces that extend between the upper and bottom surfaces. Cutting edges are formed at the transitions between the side surfaces and the upper surface. Disposed along the cutting edges on the upper surface are elongated primary lands. Disposed inside of the lands is a chip-breaking depression. A raised land area to be ground is situated in the chip-breaker, so that the total grinding area of the upper surface becomes about as large as the total grinding area of the bottom surface. The insert can thus be ground by upper and lower grinding wheels which rotate simultaneously in opposite directions.

Abstract: A tool for cutting metal machining comprises one or several cutting insert seats (1), each one for an indexable cutting insert, each insert seat comprising a bottom support surface (10) and at least two side surfaces, which form a right angle with each other. One of these side surfaces comprises two side surfaces (12, 16), which are located at different distances from the bottom support surface (10), one of these being intended as a support surface for square cutting inserts and the other as a support surface for specially shaped hexagonal inserts. In this way, one and the same insert seat can accommodate either a square or a hexagonal cutting insert, which considerably improves cutting economy.

Abstract: A metal cutting insert includes a cemented carbide body having a cutting edge and a hole therein for receiving a fastening screw. The hole includes female screw threads for being screw threaded to the fastening screw. The insert is made by a process involving injection molding and sintering steps.

Abstract: A shaft tool for metal cutting machining, includes a cutting portion and a shaft portion. The cutting portion includes a fist part formed with a cutting edge, and a second part formed with an external screw thread. The first and second parts are of one-piece integral construction. The shaft portion includes an internal screw thread to which the external screw thread is removably secured.

Abstract: A double-sided milling cutting insert has two parallel main surfaces which are turned 90.degree. relative to each other. Each main surface comprises four operative cutting corners. In each cutting corner there are two bevelled surfaces which are angled relative to the plane of the main surface. Four side surfaces are angled in order to make possible a positive cutting geometry.