Abstract: A sound processing device includes an amplifier, a current detector, and a controller. The amplifier amplifies a sound signal to drive a loudspeaker. The current detector detects a value of an electric current flowing into the amplifier. The controller controls whether to supply power to the amplifier based on a predicted current value and the current detected by the current detector. The predicted current value is predicted in accordance with a volume setting and a level of the sound signal.

Abstract: A sound processing device includes an amplifier, a current detector, and a controller. The amplifier amplifies a sound signal to drive a loudspeaker. The current detector detects a value of an electric current flowing into the amplifier. The controller controls whether to supply power to the amplifier based on a predicted current value and the current detected by the current detector. The predicted current value is predicted in accordance with a volume setting and a level of the sound signal.

Abstract: Disclosed is a technique for reducing noise superimposed on an output signal while keeping loop gain constant without increasing the circuit scale and without changing the transfer function of the amplifier apparatus (frequency characteristics of gain and phase). According to the technique, there are included a power-supply voltage control unit 7 for detecting the amplitude level S9 of an input audio signal S1 and outputting power with a voltage value indicated by target set voltage value information Vs corresponding to this amplitude level S9, and a PWM modulation unit 2 including a PWM converter 23 for converting the pulse width of the input audio signal S1 and a correction unit for correcting the signal modulated by the PWM converter 23. The PWM modulation unit 2 corrects the pulse width of a PWM signal S5 modulated by the PWM converter 23 so that the correction unit will cancel out a change in amplification gain of a power amplification unit 4 according to the target set voltage value information Vs.

Abstract: Because of input of a digital signal, PWM-input, separately excited, class-D amplifier systems are less prone to be affected by noise than in the conventional case that an analog signal is input. Since a ramp wave that is synchronized with a PWM signal is used as a comparison clock, no beats occur between a PWM clock and a reference clock, making is possible to provide a class-D amplifier system which exhibits a large S/N ratio. Furthermore, the fact that an external clock can be varied provides another advantage that no beat noise occurs even in a set that is disposed close to a radio receiver.

Abstract: An amplifier is capable of reducing the quantization error caused by conversion accuracy in an A/D converter circuit and, particularly, capable of improving the S/N ratio and distortion rate when an input audio signal is small. In an amplifier (1) using a voltage variable power supply (73) as a power supply to follow an input audio signal level (S1) to the amplifier (1) in order to increase or decrease the level of supply voltage supplied to a power amplifier stage (4), when the level of source power of the power amplifier stage (4) is changed, the voltage level of a reference voltage supplied to an A/D converter (62) of a negative feedback circuit is controlled.

Abstract: Disclosed is a technique for reducing noise superimposed on an output signal while keeping loop gain constant without increasing the circuit scale and without changing the transfer function of the amplifier apparatus (frequency characteristics of gain and phase). According to the technique, there are included a power-supply voltage control unit 7 for detecting the amplitude level S9 of an input audio signal S1 and outputting power with a voltage value indicated by target set voltage value information Vs corresponding to this amplitude level S9, and a PWM modulation unit 2 including a PWM converter 23 for converting the pulse width of the input audio signal S1 and a correction unit for correcting the signal modulated by the PWM converter 23. The PWM modulation unit 2 corrects the pulse width of a PWM signal S5 modulated by the PWM converter 23 so that the correction unit will cancel out a change in amplification gain of a power amplification unit 4 according to the target set voltage value information Vs.

Abstract: A controller 103 that conducts various controls corresponding to input information selects target voltage information and target dead time information corresponding to input audio signal level information from data table information, outputs the target voltage information to a variable power supply unit 104, and outputs the target dead time information associated with the target voltage information to a dead time generator 105, to thereby set an output supply voltage and a dead time corresponding to an input audio signal level in a half bridge circuit 107. Accordingly, there can be provided a class D amplification device that can minimize the dead time and reduce distortion while suppressing the amount of heat generation caused by a through-current.

Abstract: Disclosed is a technique for reducing noise superimposed on an output signal while keeping loop gain constant without increasing the circuit scale and without changing the transfer function of the amplifier apparatus (frequency characteristics of gain and phase). According to the technique, there are included a power-supply voltage control unit 7 for detecting the amplitude level S9 of an input audio signal S1 and outputting power with a voltage value indicated by target set voltage value information Vs corresponding to this amplitude level S9, and a PWM modulation unit 2 including a PWM converter 23 for converting the pulse width of the input audio signal S1 and a correction unit for correcting the signal modulated by the PWM converter 23. The PWM modulation unit 2 corrects the pulse width of a PWM signal S5 modulated by the PWM converter 23 so that the correction unit will cancel out a change in amplification gain of a power amplification unit 4 according to the target set voltage value information Vs.

Abstract: A supply voltage controller 11 includes a simplified envelope creating unit 111 that calculates an envelope of an input audio signal according to an input audio signal from an external device, creates a supply voltage control signal so that a waveform of the supply voltage control signal follows a waveform of the envelope, and outputs the supply voltage control signal to a voltage variable power supply 12 a constant time before the input audio signal is amplified by the amplifier 14. Accordingly, an amplifying device can be provided which can reduce the distortion of the output signal not depending on a change in the slew rate of the voltage variable power supply 12 and suppress the deterioration of power efficiency.

Abstract: Because of input of a digital signal, PWM-input, separately excited, class-D amplifier systems are less prone to be affected by noise than in the conventional case that an analog signal is input. Since a ramp wave that is synchronized with a PWM signal is used as a comparison clock, no beats occur between a PWM clock and a reference clock, making is possible to provide a class-D amplifier system which exhibits a large S/N ratio. Furthermore, the fact that an external clock can be varied provides another advantage that no beat noise occurs even in a set that is disposed close to a radio receiver.

Abstract: [Problem] The purpose is to provide an amplifier capable of reducing the quantization error caused by conversion accuracy in an A/D converter circuit and, particularly, capable of improving the S/N ratio and distortion rate when an input audio signal is small. [Solution] In an amplifier (1) using a voltage variable power supply (73) as a power supply to follow an input audio signal level (S1) to the amplifier (1) in order to increase or decrease the level of supply voltage supplied to a power amplifier stage (4), when the level of source power of the power amplifier stage (4) is changed, the voltage level of a reference voltage supplied to an A/D converter (62) of a negative feedback circuit is controlled.

Abstract: Disclosed is a technique for reducing noise superimposed on an output signal while keeping loop gain constant without increasing the circuit scale and without changing the transfer function of the amplifier apparatus (frequency characteristics of gain and phase). According to the technique, there are included a power-supply voltage control unit 7 for detecting the amplitude level S9 of an input audio signal S1 and outputting power with a voltage value indicated by target set voltage value information Vs corresponding to this amplitude level S9, and a PWM modulation unit 2 including a PWM converter 23 for converting the pulse width of the input audio signal S1 and a correction unit for correcting the signal modulated by the PWM converter 23. The PWM modulation unit 2 corrects the pulse width of a PWM signal S5 modulated by the PWM converter 23 so that the correction unit will cancel out a change in amplification gain of a power amplification unit 4 according to the target set voltage value information Vs.

Abstract: Disclosed is an amplifier with which output signal distortion can be reduced, and deterioration in power efficiency can be reduced. The amplifier is provided with a power supply voltage control unit (11) that generates a voltage control signal from a simple envelope of an input signal in order to control a variable voltage power supply (12). The power supply voltage control unit (11) is composed of: a slope comparison processing unit (112) that calculates the slope required to generate a voltage control signal; a total delay time calculation unit (113) that calculates the sum of the delay times between the dots produced by the slope comparison process; and a voltage control signal generation unit (114) that generates a voltage control signal in such a manner that the waveform formed by the voltage control signal, which controls the variable voltage power supply (12), constitutes a waveform that reflects the selected slope or the sum of the slew rate and delay time.

Abstract: A supply voltage controller 11 includes a simplified envelope creating unit 111 that calculates an envelope of an input audio signal according to an input audio signal from an external device, creates a supply voltage control signal so that a waveform of the supply voltage control signal follows a waveform of the envelope, and outputs the supply voltage control signal to a voltage variable power supply 12 a constant time before the input audio signal is amplified by the amplifier 14. Accordingly, an amplifying device can be provided which can reduce the distortion of the output signal not depending on a change in the slew rate of the voltage variable power supply 12 and suppress the deterioration of power efficiency.

Abstract: A controller 103 that conducts various controls corresponding to input information selects target voltage information and target dead time information corresponding to input audio signal level information from data table information, outputs the target voltage information to a variable power supply unit 104, and outputs the target dead time information associated with the target voltage information to a dead time generator 105, to thereby set an output supply voltage and a dead time corresponding to an input audio signal level in a half bridge circuit 107. Accordingly, there can be provided a class D amplification device that can minimize the dead time and reduce distortion while suppressing the amount of heat generation caused by a through-current.

Abstract: Weight data of articles for sale is stored and a total weight is calculated every order. Measured weight of the prepared articles in a package is compared with the calculated total weight. If the measured weight substantially disagrees with the calculated total weight, error information is provided to the operator to correctly package the articles. Comparison may be effected every order number. An addition flag may be further stored with weight data every article to indicate that the article is a target of weight measuring. A non-addition key indicating that the corresponding article is not packaged may be further provided. When the non-addition key is depressed, the weight of the corresponding article is not included in the total weight. The total weight may be printed on the receipt, so that the operator can compare the printed total weight with the measured weight. The total weight may be printed with bar codes. A balance has a bar code reader for comparison.