Abstract: A corner bead for finishing a wallboard corner joint is provided, including a plastic body including a first flange and a second flange, each flange having a rib edge and an opposite free edge. The respective rib edges are joined to form a corner rib defining an angle. A web of face paper covers at least a portion of the body.

Abstract: An elongated grid runner, and its manufacture, comprising a pair of overlying metal strips roll-formed together into a shape suitable for use in a rectangular grid to support ceiling panels, one of said strips serving as a visible cap for concealing the other strip forming the main body of the grid runner when the grid member is employed in a completed ceiling, the strips being lanced at each end of the grid runner to lock the cap strip on the main body strip whereby when the overlying strips are simultaneously cut to a finish length prior to finish roll-forming, the ends of the strip are maintained in substantially overlying end-to-end registration where the cap is visible in a finished ceiling.

Abstract: An elongated grid runner, and its manufacture, comprising a pair of overlying metal strips roll-formed together into a shape suitable for use in a rectangular grid to support ceiling panels, one of said strips serving as a visible cap for concealing the other strip forming the main body of the grid runner when the grid member is employed in a completed ceiling, the strips being lanced at each end of the grid runner to lock the cap strip on the main body strip whereby when the overlying strips are simultaneously cut to a finish length prior to finish roll-forming, the ends of the strip are maintained in substantially overlying end-to-end registration where the cap is visible in a finished ceiling.

Abstract: An elongated grid runner, and its manufacture, comprising a pair of overlying metal strips roll-formed together into a shape suitable for use in a rectangular grid to support ceiling panels, one of said strips serving as a visible cap for concealing the other strip forming the main body of the grid runner when the grid member is employed in a completed ceiling, the strips being lanced at each end of the grid runner to lock the cap strip on the main body strip whereby when the overlying strips are simultaneously cut to a finish length prior to finish roll-forming, the ends of the strip are maintained in substantially overlying end-to-end registration where the cap is visible in a finished ceiling.

Abstract: A corner bead for finishing a wallboard corner joint is provided, including a plastic body including a first flange and a second flange, each flange having a rib edge and an opposite free edge. The respective rib edges are joined to form a corner rib defining an angle. A web of face paper covers at least a portion of the body.

Abstract: A narrow band modem for communicating with a remote modem may include a narrow band modulator for modulating data for transmission to the remote modem, and a narrow band demodulator for demodulating digital data from the remote modem. More particularly, the narrow band demodulator may include an input for receiving a modulated narrow band signal based upon a carrier frequency signal and a periodically inserted level over a predetermined portion of a carrier cycle and representing digital data. The demodulator may further include a frequency domain converter for converting the modulated narrow band signal into frequency domain components, and a data translator for translating the frequency domain components into the digital data based upon levels at the carrier frequency component.

Abstract: A narrow band signal demodulation method may include receiving a modulated narrow band signal based upon a carrier frequency signal and a level periodically inserted over a predetermined portion of a carrier cycle and representing digital data. The method may further include converting the modulated narrow band signal into frequency domain components, and translating the frequency domain components into the digital data based upon levels at the carrier frequency component. By way of example, the predetermined portion of the carrier cycle may be one full carrier cycle. Thus, received digital data may have been mapped into a first corresponding level during a first half-cycle of the full carrier cycle, and into a second corresponding level during a second half-cycle of the full carrier cycle.

Abstract: A narrow band signal modulation method may include receiving digital data to be modulated, mapping the digital data to at least one of a plurality of different levels, and generating a carrier at a predetermined frequency. The method may further include generating a gating control signal every predetermined number of cycles of the carrier, outputting the at least one level for a predetermined portion of a carrier cycle responsive to the gating control signal, and outputting the carrier otherwise.

Abstract: A narrow band modem for communicating with a remote modem may include a narrow band demodulator for demodulating digital data from the remote modem and a narrow band modulator for modulating digital data for transmission to the remote modem. In particular, the narrow band modulator may include an input for receiving digital data to be modulated, a level mapper for mapping the digital data to at least one of a plurality of different levels, and a carrier generator for generating a carrier at a predetermined frequency. In addition, the narrow band modulator may also include a counter for generating a gating control signal every predetermined number of cycles of the carrier, and a gating device outputting the level from the level mapper for a predetermined portion of a carrier cycle responsive to the gating control signal, and for outputting the carrier otherwise.

Abstract: Electronic outdoor warning siren systems which include a plurality of speakers arranged in one or more vertically spaced circular arrays of circumferentially spaced vertically oriented speakers to achieve substantially uniform coverage in all radial directions in a horizontal plane, and utilizing frequency variations in adjacent speakers in a given horizontal plane to minimize interference between sound signals from adjacent speakers thereby permitting closer spacing of speakers than would otherwise be feasible and providing uniform omni-directional sound propagation. The same frequency variations are also employed with a plurality of speakers oriented in the same direction and rotated through 360.degree. to accomplish the same result of minimal interference and more uniform sound propagation.