68results about "Limiting amplitude of digital/coded signals" patented technology

A distortion compensation system minimizes distortion in an audio system by monitoring a supply voltage and adjusting a clipping threshold and / or compression knee. An adjustable gain circuit controls the gain of the audio signal according whether the audio signal exceeds a variable threshold. The variable threshold is adjusted within a threshold range based on the supply voltage. Distortion due to clipping of the audio signal is minimized while available power at any given time is maximized.

An apparatus and method of automatically compensating audio volume in response to a channel change. The method includes generating a gain value to adjust a level of an input audio signal by comparing an average level of the input audio signal with a predetermined input / output level curve, adjusting an audio volume of the input audio signal by applying the generated gain value to the level of the input audio signal, and adjusting a dynamic range of the audio signal having the adjusted audio volume.

A class D amplifier (1) comprises an input unit (11) for receiving a digital input signal (Vin), a pulse shaping unit (12) for producing pulse shaped signals in dependence of the input signal (Vin), a comparator unit (13) for comparing the pulse shaped signals and producing a comparator signal, a driver unit (14) for producing driver signals in dependence of the comparator signal, a switching output unit (15) for producing a pulse width modulated output signal (Vout) in dependence of the driver signals, and a feedback unit (16) for feeding the output signal (Vout) back to the pulse shaping unit (12). The input unit (11) comprises a clipping control unit (10) for controlling the duty cycle of the pulse width modulated output signal (Vout).

A method and apparatus for limiting the absolute magnitude of an audio signal. The method may include firstly variable-gain reducing the gain of an audio signal, and then secondly variable-gain reducing the gain of the audio signal faster than the first variable-gain reduction, thereby limiting the absolute magnitude of the audio signal to a threshold. The first variable-gain reduction may include variable-gain reducing the gain of the audio signal in a first stage, and the second variable-gain reduction may include variable-gain reducing the gain of the audio signal in a second stage that reduces the gain faster than the first stage. The second variable-gain reduction may include delaying the audio signal, finding a peak among the delayed audio signal, calculating a fast gain from a found peak, and modifying the delayed audio signal with the calculated fast gain.

A method and apparatus for limiting the absolute magnitude of an audio signal. The method may include firstly variable-gain reducing the gain of an audio signal, and then secondly variable-gain reducing the gain of the audio signal faster than the first variable-gain reduction, thereby limiting the absolute magnitude of the audio signal to a threshold. The first variable-gain reduction may include variable-gain reducing the gain of the audio signal in a first stage, and the second variable-gain reduction may include variable-gain reducing the gain of the audio signal in a second stage that reduces the gain faster than the first stage. The second variable-gain reduction may include delaying the audio signal, finding a peak among the delayed audio signal, calculating a fast gain from a found peak, and modifying the delayed audio signal with the calculated fast gain.

An audio driver comprising a distortion detection unit coupled between an amplifier and a loudspeaker and configured to detect a distortion signal generated by the loudspeaker while the loudspeaker is being used to deliver an audio signal from the amplifier. A distortion compensation unit configured to compensate for the distortion signal without interfering with the audio signal.

A transmitter includes: a limiter performing clipping in which an amplitude part at a level higher than an amplitude level based on a predetermined clipping level is clipped from an input signal, separating the input signal into an input signal after the clipping, which contains a predetermined out-of-band component, and a clip signal clipped from the input signal through the clipping, and outputting the input signal after the clipping and the clip signal; a high-pass filter subjecting the clip signal inputted from the limiter to high-pass filtering for blocking an in-band component contained in the clip signal while passing an out-of-band component contained in the clip signal, which is opposite in phase to the out-of-band component contained in the input signal after the clipping; an adder performing an addition process on the out-of-band component received from the high-pass filter and the input signal after the clipping received from the limiter; and an amplifier performing power amplification on a signal outputted from the adder, and outputting the amplified signal.