Abstract: The disclosure provides a communication system and a program update method. In a communication system according to the disclosure, when a host device updates a program stored in each of a plurality of communication terminals, first, the host device transmits a distribution preparation completion signal by broadcast. Each of the plurality of communication terminals transmits a start request signal to the host device in response to reception of the distribution preparation completion signal. The host device transmits a permission signal for giving a right for performing a data request to one communication terminal that has transmitted the start request signal earliest. The one communication terminal transmits a data request signal to the host device in response to reception of the permission signal. The host device transmits the update program data by broadcast to the plurality of communication terminals in response to reception of the data request signal.

Abstract: The disclosure provides a communication system and a program update method. In a communication system according to the disclosure, when a host device updates a program stored in each of a plurality of communication terminals, first, the host device transmits a distribution preparation completion signal by broadcast. Each of the plurality of communication terminals transmits a start request signal to the host device in response to reception of the distribution preparation completion signal. The host device transmits a permission signal for giving a right for performing a data request to one communication terminal that has transmitted the start request signal earliest. The one communication terminal transmits a data request signal to the host device in response to reception of the permission signal. The host device transmits the update program data by broadcast to the plurality of communication terminals in response to reception of the data request signal.

Abstract: An audio output circuit drives an electroacoustic conversion element. A Class D amplifier has a segmented configuration including multiple segments arranged in parallel. A pulse modulator pulse modulates an audio signal. A level detector detects the amplitude of the audio signal. A driver selectively drives the multiple segments of the Class D amplifier according to the output of the level detector.

Abstract: An audio output circuit drives an electroacoustic conversion element. A Class D amplifier has a segmented configuration including multiple segments arranged in parallel. A pulse modulator pulse modulates an audio signal. A level detector detects the amplitude of the audio signal. A driver selectively drives the multiple segments of the Class D amplifier according to the output of the level detector.

Abstract: A signal processing device includes a first amplifier, a converter, a signal processor, a controller, and a second amplifier. The first amplifier amplifies a level of an externally input analog audio signal with a first gain whose value is variable. The converter converts the analog audio signal amplified by the first amplifier into a digital audio signal. The signal processor that performs tone control signal processing on the digital audio signal. The controller detects a level of the digital audio signal before the signal processing and controls the value of the first gain in accordance with the detected level. The second amplifier detects a level of the digital audio signal after the signal processing and amplifies the digital audio signal after the signal processing with a second gain determined in accordance with the detected level and the first gain whose value has been controlled by the controller.

Abstract: In a signal processing apparatus, a high frequency level detecting unit detects a level of a high frequency component adjusted with a first adjusting unit, and a first control unit controls a first gain of the adjusting unit according to the level of the high frequency component thus detected. Further, a low frequency level detecting unit detects a level of a low frequency component adjusted with a second adjusting unit. A second control unit controls a second gain according to the level of the high frequency component and the level of the low frequency component thus adjusted, so that a difference between the level of the high frequency component adjusted with the first adjusting unit and the level of the low frequency component adjusted with the second adjusting unit becomes smaller than a specific level determined in advance.

Abstract: This method is applied to a dual-use jack of an electronic device. Either a headphone plug or a line output plug is inserted into the dual-use jack. The method determines the type of a plug connected to the dual-use jack when the plug is inserted into the dual-use jack. The determination is made based on a load resistance of the plug connected to the jack. The method includes feeding an electric current through the load resistance in a first direction. The method compares a voltage across the load resistance to a reference voltage and determines the type of the plug in use. The method also includes feeding an electric current through the load resistance in a second direction. This electric current can reduce or eliminate a pop-noise when the plug type is determined. The second direction is different from the first direction.

Abstract: A sound effect circuit and processing method are disclosed. An input audio signal is input to a digital sound effect unit, an output signal is generated and output with a sound effect in accordance with an effect amount of a certain value from the input audio signal using the digital sound effect unit, the input audio signal is also input to a silence state detection unit, a silence detect signal is generated and output when detecting that the current state of the input audio signal is a silence state using the silence state detection unit, the output signal is input to a sound effect amount control unit, and an output audio signal is output using the sound effect amount control unit, wherein the sound effect amount control unit changes the effect amount to be smaller than the certain value when the silence detect signal is generated.

Abstract: An apparatus for performing processing of an input acoustic signal to be reproduced by a loudspeaker, which generates a harmonic of a low pitch sound component equal to or lower than a predetermined low cutoff frequency, and generates a harmonic synthesized acoustic signal synthesizing the input signal with the harmonic. The apparatus generates an output acoustic signal which cuts off, from the harmonic synthesized acoustic signal, a low pitch sound component equal to or lower than the low cutoff frequency and a high pitch sound component equal to or higher than the high cutoff frequency. The apparatus sets a low and high cutoff frequencies in accordance with an output characteristic of a loudspeaker.

Abstract: In a signal processing apparatus, a high frequency level detecting unit detects a level of a high frequency component adjusted with a first adjusting unit, and a first control unit controls a first gain of the adjusting unit according to the level of the high frequency component thus detected. Further, a low frequency level detecting unit detects a level of a low frequency component adjusted with a second adjusting unit. A second control unit controls a second gain according to the level of the high frequency component and the level of the low frequency component thus adjusted, so that a difference between the level of the high frequency component adjusted with the first adjusting unit and the level of the low frequency component adjusted with the second adjusting unit becomes smaller than a specific level determined in advance.

Abstract: A signal processing device includes a first amplifier, a converter, a signal processor, a controller, and a second amplifier. The first amplifier amplifies a level of an externally input analog audio signal with a first gain whose value is variable. The converter converts the analog audio signal amplified by the first amplifier into a digital audio signal. The signal processor that performs tone control signal processing on the digital audio signal. The controller detects a level of the digital audio signal before the signal processing and controls the value of the first gain in accordance with the detected level. The second amplifier detects a level of the digital audio signal after the signal processing and amplifies the digital audio signal after the signal processing with a second gain determined in accordance with the detected level and the first gain whose value has been controlled by the controller.

Abstract: A signal processing device includes a non-inverting amplifier, an inverting amplifier, a converter, and a controller. The non-inverting amplifier amplifies a level of an analog sound signal input from outside with a first gain whose value is variable. The inverting amplifier amplifies a level of the analog sound signal amplified by the non-inverting amplifier with a second gain whose value is variable. The converter converts the analog sound signal amplified by the inverting amplifier to a digital sound signal. The controller detects a level of the digital sound signal converted by the converter and, in accordance with the detected level of the digital sound signal converted by the converter, controls the first gain and the second gain such that a level of the analog sound signal input to the converter is at a pre-specified level.

Abstract: This method is applied to a dual-use jack of an electronic device. Either a headphone plug or a line output plug is inserted into the dual-use jack. The method determines the type of a plug connected to the dual-use jack when the plug is inserted into the dual-use jack. The determination is made based on a load resistance of the plug connected to the jack. The method includes feeding an electric current through the load resistance in a first direction. The method compares a voltage across the load resistance to a reference voltage and determines the type of the plug in use. The method also includes feeding an electric current through the load resistance in a second direction. This electric current can reduce or eliminate a pop-noise when the plug type is determined. The second direction is different from the first direction.

Abstract: A CLK generating section of a digital ALC generates a multiplication clock signal that is obtained by multiplying a triangular wave generated at a triangular wave generating circuit. On the basis of the multiplication clock signal, a signal converting section converts a one-bit digital audio signal outputted from an outputting stage into a multi-bit digital signal, and monitors a voltage value of an input signal. A level controlling section controls a voltage level on the basis of a target level inputted from an exterior of an LSI. On the basis of a control signal inputted from an exterior of the LSI, a volume controlling section outputs, to a PGA, a gain adjusting signal so as to vary a waveform of an input signal.

Abstract: A CLK generating section of a digital ALC generates a multiplication clock signal that is obtained by multiplying a triangular wave generated at a triangular wave generating circuit. On the basis of the multiplication clock signal, a signal converting section converts a one-bit digital audio signal outputted from an outputting stage into a multi-bit digital signal, and monitors a voltage value of an input signal. A level controlling section controls a voltage level on the basis of a target level inputted from an exterior of an LSI. On the basis of a control signal inputted from an exterior of the LSI, a volume controlling section outputs, to a PGA, a gain adjusting signal so as to vary a waveform of an input signal.

Abstract: A sound effect circuit and processing method are disclosed. An input audio signal is input to a digital sound effect unit, an output signal is generated and output with a sound effect in accordance with an effect amount of a certain value from the input audio signal using the digital sound effect unit, the input audio signal is also input to a silence state detection unit, a silence detect signal is generated and output when detecting that the current state of the input audio signal is a silence state using the silence state detection unit, the output signal is input to a sound effect amount control unit, and an output audio signal is output using the sound effect amount control unit, wherein the sound effect amount control unit changes the effect amount to be smaller than the certain value when the silence detect signal is generated.

Abstract: An apparatus for performing processing of an input acoustic signal to be reproduced by a loudspeaker, which generates a harmonic of a low pitch sound component equal to or lower than a predetermined low cutoff frequency, and generates a harmonic synthesized acoustic signal synthesizing the input signal with the harmonic. The apparatus generates an output acoustic signal which cuts off, from the harmonic synthesized acoustic signal, a low pitch sound component equal to or lower than the low cutoff frequency and a high pitch sound component equal to or higher than the high cutoff frequency. The apparatus sets a low and high cutoff frequencies in accordance with an output characteristic of a loudspeaker.