Abstract: An apparatus and method is disclosed for using adaptive algorithms to exploit sparsity in target weight vectors in an adaptive channel equalizer. An adaptive algorithm comprises a selected value of a prior and a selected value of a cost function. The present invention comprises algorithms adapted for calculating adaptive equalizer coefficients for sparse transmission channels. The present invention provides sparse algorithms in the form of a Sparse Least Mean Squares (LMS) algorithm and a Sparse Constant Modulus Algorithm (CMA) and a Sparse Decision Directed (DD) algorithm.

Abstract: An electrostatic loudspeaker includes a high resistivity stator with electrode conductivity per square that is constant and/or decreases with distance from the connection point. A contact area of predetermined size is related to the highest frequency of interest. The constant or decreasing surface resistivity of the stators, interacting with the capacitive load of the stator to stator gap, operates as a distributed network such that the active acoustic output is attenuated in a predetermined manner with increased frequency at all points equidistant on the stator from the connection area. The apparent acoustic source size is reduced as the frequency increases to maintain enhanced dispersion across the operating range of the loudspeaker system.

Abstract: An electrostatic loudspeaker includes a high resistivity stator with electrode conductivity per square that is constant and/or decreases with distance from the connection point. A contact area of predetermined size is related to the highest frequency of interest. The constant or decreasing surface resistivity of the stators, interacting with the capacitive load of the stator to stator gap, operates as a distributed network such that the active acoustic output is attenuated in a predetermined manner with increased frequency at all points equidistant on the stator from the connection area. The apparent acoustic source size is reduced as the frequency increases to maintain enhanced dispersion across the operating range of the loudspeaker system.

Abstract: An apparatus and method is disclosed for using adaptive algorithms to exploit sparsity in target weight vectors in an adaptive channel equalizer. An adaptive algorithm comprises a selected value of a prior and a selected value of a cost function. The present invention comprises algorithms adapted for calculating adaptive equalizer coefficients for sparse transmission channels. The present invention provides sparse algorithms in the form of a Sparse Least Mean Squares (LMS) algorithm and a Sparse Constant Modulus Algorithm (CMA) and a Sparse Decision Directed (DD) algorithm.

Abstract: Disclosed is a loudspeaker apparatus having at least one support surface provided therein adjacent to a complaint surround for providing lateral support thereto, the surround mounting the diaphragm of the speaker to a speaker frame for permitting longitudinal movement of the diaphragm with respect to the frame. The support surface may be used with a variety of surrounds. A second support surface may also be provided. The support surfaces may be contoured to achieve a desired response from their engagement with the surround. A negative air spring is formed from a pair of opposed support surfaces contoured to form a necked region therebetween for deformingly engaging a surround formed as a resilient member. The negative air spring negatively balances, or counterbalances the diphragm against the box pressures with the enclosure. The resilient member is formed as a tube for containing a fluid such as air therein. The pressure within the resilient member is controlled in response to a variety of parameters.

Abstract: An inverter for an audio amplifier. The inverter comprises a current damped feedback loop for actively damping oscillations caused by an output inductor within the inverter. A forward compensator is provided to compensate for the frequency response of the actively damped filter. The resulting inverter generates an output voltage that tracks an input voltage thereof with improved frequency response within the frequency range of interest.

Abstract: An inverter for an audio amplifier. The inverter comprises a current damping feedback loop for actively damping oscillations caused by an output inductor within the inverter. A forward compensator is provided to compensate for the frequency response of the actively damped filter. The resulting inverter generates an output voltage that tracks an input voltage thereof with improved frequency response within the frequency range of interest.

Abstract: An audio frequency amplifier having a switching converter comprising source and sink rectifiers configured for sourcing and sinking current, in which the source and sink supply voltages of the rectifiers track the audio frequency signal being amplified. The amplifier has a circuit or element for discharging the output capacitors of the source and sink rectifier as necessary to prevent floating of the source and sink supply voltages. The discharging element can be a locking capacitor or one or more Zener diodes connected across the source and sink supply voltages. The discharge circuit can be one or more switching transistors connected across the freewheeling diodes of the source and sink rectifiers to actively pull the source and sink voltages down to discharge the output capacitors and thereby prevent floating. Low voltage rated parts can be used in the output stage amplifier, and in certain configurations a high voltage low current preamplifier stage can be eliminated.