Abstract: An earpiece for a headset, especially a headset incorporating active unwanted noise suppression, wherein the earshell incorporates a baffle plate carrying a sound drive and an ear cushion, whereby the baffle plate also carries an upstanding projection, more especially in the form of a sound transparent dome, which limits the extent to which the cushion can be compressed when the earpiece is pressed inwardly against the ear from its normally fitted condition.

Abstract: Methods and structures for ensuring the highly linear discharge of a capacitor used for slew rate control of a power driving stage from a maximum voltage to a minimum supply voltage, such as ground. A voltage ramp generator uses a single cascoded current source to achieve the linear ramp-down.

Abstract: A network of centrally controlled, customizable digital broadcast stations capable of broadcasting music, videos, audible advertisements, and visual advertisements is disclosed. The invention includes a program database, a station demographic database, a central controller, and a plurality of digital broadcast stations. The central controller includes one or more servers, multiple computer workstations, and multiple call directors. Each digital broadcast station includes a computer, a loudspeaker(s), and a microphone. Optionally, a digital broadcast station may include a projector(s) or flat screen television(s). The central controller completely controls the broadcast content and broadcast schedule of the plurality of digital broadcast stations. The present invention allows advertisers to conduct targeted advertising campaigns within the network of digital broadcast stations.

Abstract: An earphone having a drive unit (22) carried by an earphone shell (20) and covered by an ear cushion (24) of auxetic foam.

Abstract: An electro-acoustic transducer comprises first and second panels (18A,18B) each of which can be vibrated to generate sound, a frame (10) for mounting the panels, and first and second seals (20A,B) arranged between the frame and the edges of the panels for holding the panels in the frame, substantially isolating the frame acoustically from the edges of the panel, and substantially sealing the frame to the edges of the panel. One or more actuators (22), such as piezoelectric elements, are provided for receiving a driving signal and vibrating in response thereto, and the actuators are mechanically and acoustically coupled to the first panel at one or more locations remote from the edges of the first panel so that the first panel vibrates in response to vibration of the actuators.

Abstract: This invention outlines several applications of piezoelectric vibrators to produce quality flat panel speakers in passenger cabin applications. A system consisting of an audio amplifier and transformer is used to drive the piezo speaker. The electronics are packaged so that they fit in small modules that can be attached to a cabin structure to produce a speaker. The invention includes a variety of flat panel speaker designs, including one in which the existing structure is converted into a speaker, and thin membrane and or panels that are fitted with piezoelectric elements. A system consisting of cabin quieting and flat panel speakers is also discussed where the mid and high frequency audio is produced by panel speakers and the low frequency audio is produced from dynamic loudspeakers. The cabin systems discussed in this patent are applicable to automobiles, aircraft, trucks and buses.

Abstract: The invention consists of an integral transducer for a sound radiating diaphragm which may consist of a piezoelectric material, a substrate or a spacer and electrical connector means for a wire harness or other electrical connection. The substrate is used to enhance the motion of the piezoelectric element by spacing the piezoelectric element from the diaphragm. The substrate is larger in area than the piezoelectric element. The transducer system acts to impart motion to a diaphragm. The transducer comprises a piezoelectric element subject to displacement by applied electric potential that has a top side, an under side and an outer perimeter; a substrate that is joined to the underside of the piezoelectric element, and means to apply electric potential to the piezoelectric element.

Abstract: This invention outlines several applications of piezoelectric vibrators to produce quality flat panel speakers in passenger cabin applications. A system consisting of an audio amplifier and transformer is used to drive the piezo speaker. The electronics are packaged so that they fit in small modules that can be attached to a cabin structure to produce a speaker. The invention includes a variety of flat panel speaker designs, including one in which the existing structure is converted into a speaker, and thin membrane and or panels that are fitted with piezoelectric elements. A system consisting of cabin quieting and flat panel speakers is also discussed where the mid and high frequency audio is produced by panel speakers and the low frequency audio is produced from dynamic loudspeakers. The cabin systems discussed in this patent are applicable to automobiles, aircraft, trucks and buses.

Abstract: The present invention is a method and apparatus for conveying audiovisual information. The invention utilizes a speaker as a visual medium. A sheet of material is secured to the radiating face of a speaker. A visual image is then displayed on the sheet of material. Different techniques can be utilized to display the visual image on the sheet of material. For example, a video image can be projected on to the sheet of material or the sheet of material can contain a fixed image. While the visual image is being displayed on the radiating face of the speaker, audible information is being broadcast over the speaker.

Abstract: An active noise cancellation system includes a series of features for more effective cancellation, greater reliability, and improved stability. A particular feature adapted for headset systems includes locating a residual microphone radially offset from the center of a sound generator to detect a signal more similar to that incident upon the eardrum of the user. In addition, an open back headset design includes perforations on the side of the headset instead of the back, so that the perforations are less susceptible to inadvertent blockage. The system also includes a mechanism for detecting changes in the acoustic characteristics of the environment that may be caused, for example, by pressure exerted upon the earpieces, and that may destabilize the cancellation system. The system automatically responds to such changes, for example, by reducing the gain or the frequency response of the system to preserve stability.

Abstract: According to the present invention, entry into the test mode of an integrated circuit device is possible even when there is no device pin dedicated to a test mode function. Test mode control circuitry allows a pin of the integrated circuit device to be double mapped to a normal operation function and to a test mode function. The test mode control circuitry has a polarity circuit having a polarity bond pad and a fuse circuit having a fuse element, either of which may determine when the polarity of the pin is representative of a test mode function. Either down-bonding the polarity bond pad to the lead frame of the integrated circuit device or blowing the fuse renders the pin representative of the test mode function. Additionally, once the test mode of the device is entered, the device may be adequately stress tested.

Abstract: A current limiting circuit used with voltage regulators or other similar circuits is disclosed. The current limiting circuit uses two transistors, configured as a differential pair, combined with a fixed current source to limit the current available to a pass transistor of the voltage regulator.

Abstract: Parallel testing of integrated circuit devices are facilitated such that it is not necessary that integrated circuit devices to be parallel tested be "ends only" devices. A side pad located along the sides, rather than the ends, of the integrated circuit device is electrically connected by multiplexing circuitry to a corresponding configurable probe pad located along the ends of the device. During parallel testing of the device, the side pad is effectively tested when the configurable probe pad is probed and tested. While the configurable probe pad is tested during parallel testing, the side pad is not directly exercised. Following parallel testing, the side pad is bonded to the device package but the configurable probe pad is not bonded to the device package.