Jl Audio, Inc.

Bruce MacMillan

Manville Smith

Carl Lindquist

Campbell Kelly

Felix Matro

A system () and method () of equalizing an audio signal from an existing radio or head unit () using an interface unit () between the radio or head unit and a replacement load () can include the steps analyzing () an existing equalization to provide a measure of an existing frequency response, generating () a substantially inverted frequency response to the existing frequency response, and applying () the inverted frequency response to the replacement load to provide a desired response. Such as system can include an interface unit () having an automatic input level control unit (), an analog to digital converter or digitizer (), a DSP () providing an output to a DAC (), a level booster unit () and a processor such as a microcontroller unit ().

Method and system for equalization of a replacement load

A system () and method () of equalizing an audio signal from a factory installed radio () using an interface unit () between the factory installed radio and a replacement load () can include the steps of measuring () an existing equalization for the factory installed radio in the interface unit, analyzing () the existing equalization to provide a measure of an existing frequency response suited for an old load, generating () a substantially inverted frequency response to the existing frequency response, and applying () the inverted frequency response to the replacement load to provide a desired response. Such as system can include an interface unit () having an automatic input level control unit (), an analog to digital converter or digitizer (), a DSP () providing an output to a DAC (), a level booster unit () and a processor such as a microcontroller unit ().

A power converter () operating in all four voltage-current quadrants includes an input voltage source (), an output current independent of an output voltage and a switching arrangement (and) enabling an output terminal () to be in common with an input terminal. The output voltage can be unconstrained by an input voltage from the input voltage source.

Method and apparatus for power conversion having a four-quadrant output

An amplifier circuit ( ) employs negative feedback and a method ( ) for providing such feedback to reduce distortion and/or an output impedance of the amplifier circuit, without adversely impacting the overall stability of the amplifier circuit. The amplifier circuit includes a forward path and a feedback path. The forward path includes at least one amplifier ( ) arranged in series with an output lowpass filter ( ). The amplifier receives a feedback-compensated input signal and amplifies the input signal to produce an amplified signal. The feedback path includes a lowpass filter ( ), a highpass filter ( ), and a summing arrangement ( ) that selectively include and exclude the output lowpass filter from the feedback loop. The feedback lowpass filter is operably coupled to an output of the output lowpass filter and attenuates high frequency components of the amplifier circuit's output signal to produce a lowpass-filtered feedback signal. The highpass filter is operably coupled to an input of the output lowpass filter and attenuates low frequency components of the output filter's input signal to produce a highpass-filtered feedback signal. The two filtered feedback signals are summed by the summing arrangement to produce a composite feedback signal for application to the forward path amplifier or amplifiers.

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Phoenix, AZ, United States of America

Bruce MacMillan