Abstract: A temperature control apparatus used with an audio amp to prevent the audio amp from overheating and noise from being generated by effectively controlling a cooling fan of the audio amp includes a power supply to supply an electrical power, a power amp to amplify an input audio signal using the electrical power supplied from the power supply, a signal detector to detect the amount of the current flowing from the power supply during a predetermined time, a temperature sensor to sense a temperature over a predetermined level generated from the power amp, and a micro controller to control a cooling fan according to the amount of current output from the signal detector and/or the temperature sensed by the temperature sensor.

Abstract: A multi-channel digital amplifier system to generate a pulse width modulation (PWM) signal having a different switching frequency in each channel, and a signal processing method thereof. The digital amplifier system includes a PWM conversion unit to convert a plurality of audio signals on a plurality of channels into low output power PWM signals having switching frequencies that are different from each other, a switching circuit unit to amplify the plurality of low output power PWM signals to a plurality of high power output PWM signals on the respective channels, and a filter unit to restore the plurality of high output power PWM signals to a plurality of analog audio signals on the respective channels.

Abstract: A method of detecting an abnormal modulation signal, and a receiver for compensating for an abnormal modulation signal are provided. The method includes demodulating an analog input signal, which has been modulated according to modulation parameters, using demodulation parameters corresponding to the modulation parameters to generate a baseband signal; sampling the baseband signal at a sampling rate; counting a number of samples having an amplitude greater than a threshold level during a detection window; and determining whether the analog input signal has been abnormally modulated, based on the number of samples counted. The receiver includes a baseband signal generator; a sampler; an abnormal modulation detector which counts a number of samples and determines whether the analog input signal has been abnormally modulated; a demodulation parameter modifier which modifies the demodulation parameters according to the determination result.

Abstract: A multi-channel digital amplifier system to generate a pulse width modulation (PWM) signal having a different switching frequency in each channel, and a signal processing method thereof. The digital amplifier system includes a PWM conversion unit to convert a plurality of audio signals on a plurality of channels into low output power PWM signals having switching frequencies that are different from each other, a switching circuit unit to amplify the plurality of low output power PWM signals to a plurality of high power output PWM signals on the respective channels, and a filter unit to restore the plurality of high output power PWM signals to a plurality of analog audio signals on the respective channels.

Abstract: A portable speaker of a portable multimedia device includes a digital amplifier to receive a digital audio signal from the portable multimedia device and to digitally process and output the received digital audio signal to a speaker unit, and a battery to supply electric power to at least one of the digital amplifier and the portable multimedia device.

Abstract: A method and apparatus to control output power of a digital amplifier capable of automatically determining an impedance of an earphone or headphone connected to a portable audio device and outputting a power that is optimized according to the impedance.

Abstract: An apparatus and method to control audio volume through adjustment of a carrier level in a D class amplifier. The apparatus includes a control unit to generate a volume control signal, a PWM unit to adjust the level of a carrier signal according to the volume control signal generated by the control unit and to generate a pulse width modulation signal by comparing the adjusted carrier signal level with the level of an input audio signal, generating; and a power amplification unit to amplify the power of the pulse width modulation signal generated by the PWM unit.

Abstract: A temperature control apparatus used with an audio amp to prevent the audio amp from overheating and noise from being generated by effectively controlling a cooling fan of the audio amp includes a power supply to supply an electrical power, a power amp to amplify an input audio signal using the electrical power supplied from the power supply, a signal detector to detect the amount of the current flowing from the power supply during a predetermined time, a temperature sensor to sense a temperature over a predetermined level generated from the power amp, and a micro controller to control a cooling fan according to the amount of current output from the signal detector and/or the temperature sensed by the temperature sensor.