Abstract: To prevent occurring of cut of communication. An AV center 2 includes a wireless communication section 22, a power supply section 25 that is for supplying power supply voltage to respective sections, and a microcomputer 21. A wireless speaker 3 includes a wireless communication section 32, a power supply section 35 that is for supplying power supply voltage to respective sections, and a microcomputer 31. The microcomputers 21 and 31 supply power supply voltage to the wireless communication sections 22 and 32 by the power supply sections 25 and 35 when the microcomputer 21 of the AV center 2 receives setting of power OFF of an audio playback system 1. And, the microcomputers 21 and 31 perform wireless communication and monitor a channel of the DFS band by the wireless communication sections 22 and 32.

Abstract: To prevent that the noise occurs at timing switching between PCM data and DSD data by a simple configuration. An AV receiver 1 includes a mute circuit 5 that mutes output from a DAC 4, a detection circuit 6 that detects that a digital audio signal is zero data and supplies a detection signal, a microcomputer 2 that supplies a control signal at timing switching from PCM data to DSD data before switches from PCM mode that the DAC 4 converts PCM data into an analog audio signal to DSD mode that the DAC 4 converts DSD data into the analog audio signal, and an AND circuit 7 that activates the mute circuit 5 in case that the detection signal from the detection circuit 6 and the control signal from the microcomputer 2 are supplied.

Abstract: In an audio processing device having a first output route and a second output route, to be able to reproduce the same audio signal as the first output rote at the second output route. A microcomputer 2 connects a Zone2 reproduction device 6 with a DAC 10 for a surround back by a switch 17 and the DAC 10 for the surround back with a surround back analog output terminal 15 by a switch 18 in case that the DSD data is reproduced at a Zone2 output route.

Abstract: A volume adjustment device includes a display section, touch panel, and a controller which displays a slide bar including a knob, receives a movement goal position of the knob, adjusts volume of an audio signal to volume value corresponding to a position of the knob, moves the knob with a moving speed of the target of which the movement is received within a normal area in case that it receives movement of the target into a limit area in which the knob cannot move to not less than lower limit over the normal area in which the knob can move freely, and moves the knob and the lower limit of the limit area from the lower limit of the limit area to the target with the same predetermined speed as expansion speed of the limit area while it expands the normal area toward the limit area side.

Abstract: To prevent temperature rise of an amplifier. An AV amplifier 1 that amplifies an audio signal includes a PWM modulator 5 that controls dynamic range of the audio signal to not more than a setting value, and a microcomputer 2 sets the setting value based on consumption current. The microcomputer 2 sets the setting value to a predetermined value (?35 dB) in case that state that consumption current is not less than a predetermined threshold (4.9 A or 3.6 A) continues for a predetermined time (2 minutes or 7.5 minutes).

Abstract: A system that includes an electronic device and a server configured to communicate via a network, and the electronic device includes first circuitry that stores firmware in a first memory of the electronic device; sends a network address of the electronic device to the server; and updates the firmware based on an update package received from the server in response to sending the network address, and the server includes second circuitry that stores, in a second memory of the server, a plurality of network addresses of a plurality of the electronic devices, and a plurality of update packages; and sends one of the plurality of update packages to the electronic device based on the network address of the electronic device which is sent from the electronic device.

Abstract: A sound field control system SY according to the present invention is provided with: a signal supply unit 210 which supplies a test signal sequence to a speaker; and an analysis unit 150 which picks up a sound including a test sound sequence emitted from a speaker based on a test signal sequence using a microphone, and which determines the sound pickup time of an initial test sound among test sounds included in the test sound sequence, wherein the analysis unit 150 detects the initial sound from the sound pickup signal picked up using the microphone, determines whether a sound is detected after the elapse of a sound emission interval, from the sound pickup time of the detected initial sound, between the initial test sound defined by the test signal sequence and an n-th (where n is an integer such that n?2) test sound emitted from the same speaker as the initial test sound, and, upon determining that the sound has been detected, determines the sound pickup time of the initial sound as the sound pickup time of

Abstract: To be able to activate a self-device when an input digital audio signal is an audio signal indicating sound. An AV receiver 1 includes a detection circuit 4 that detects that a digital audio signal terminal is connected and supplies a detection signal, a DIR 5 that converts an SPDIF signal into an I2S signal when the detection circuit 4 supplies the detection signal, a detection circuit 7 that detects that the I2S signal into which the DIR 5 convers is an audio signal indicating sound and supplies a detection signal, and a microcomputer 2 that activates the AV receiver 1 when the detection circuit 7 supplies the detection signal.

Abstract: A music reproducing device has a controller configured to perform volume control on audio data; a digital-to-analog (D/A) converter operatively coupled to the controller and configured to convert the audio data from digital audio data to analog audio data, and to perform volume control on the audio data; and a plurality of different types of audio outputs, including at least one headphone output for outputting the audio data from the D/A converter to one or more headphones; the controller and the D/A converter configured to perform different types of volume control on the audio data, the controller performing all volume control except the volume control related to only the at least one headphone output among the multiple volume control, and the D/A converter performing one or more types of volume control which relate only to the at least one headphone output.

Abstract: To operate a switching power supply again automatically (automatic return) after the switching power supply is stopped for protection. A protection circuit 6 includes a bipolar transistor Q1 that becomes ON state and sets current that flows to a photo coupler 62 larger in case that a temperature detection element 63 supplies a detection signal, a control IC 4 that controls a switching element 3, and a protection power supply circuit 66 that includes a condenser C3 that is charged by output voltage from the switching power supply 1. Power supply voltage form the protection power supply circuit 66 is supplied to the temperature detection circuit 63 and the photo coupler 62. Further, in case that voltage value that is changed by the photo coupler 62 is not more than a predetermined value, the control IC 4 stops the switching element 3.

Abstract: A sound field control system SY according to the present invention is provided with: a sound emission unit 210 which causes a plurality of speakers to emit a test sound; a sound pickup unit 130 which picks up the test sound using a microphone; an analysis unit 150 which compares information indicating a sound emission timing of a test signal sequence for causing the speakers to successively emit the test sound at a prescribed timing with a sound pickup timing of each test sound that has been picked up, and which calculates a time difference between the sound emission timing of each test sound and the sound pickup timing; and a signal processing unit 230 which performs, based on the calculated time difference between the sound emission timing of each test sound and the sound pickup timing, a delay process for a voice signal supplied to each speaker.

Abstract: An acoustic diaphragm which has excellent Young's modulus and internal loss (tan ?) values is provided. The acoustic diaphragm according to the present invention is made from papermaking material substantially solely including cellulose nanofibers. In one embodiment, the cellulose nanofibers are unoxidized cellulose nanofibers.

Abstract: To provide a protection circuit that can reduce output voltage that is output from a switching power supply greatly when temperature rises. A protection circuit includes a comparator that supplies detection current based on voltage Vsens that a temperature sensor outputs in case that voltage Vsens that the temperature sensor outputs exceeds voltage Vref of predetermined potential, a control circuit that supplies control current that the control circuit increases detection current that the comparator supplies exponentially, and a constant voltage circuit reduces output voltage Vout that is output from a switching power supply based on control current that the control circuit supplies.

Abstract: Provided is a modulation circuit that can correct an output state in real time and reliably modulate an input signal to output the modulated signal. The signal modulation circuit includes a subtractor, an integrator, a chopper circuit, a frequency divider, and a D-type flip-flop. A delay circuit of a sigma delta modulation circuit is not provided to a feedback circuit, and a signal is delayed and quantized in the D-type flip-flop. The chopper circuit inserts a zero level at timing synchronized with a clock signal, so that pulse density modulation is performed.

Abstract: To be easy for a user to judge difference of sound quality of an audio signal that is output in a balanced mode and sound quality of the audio signal that is output in an active control ground mode. A DAP 1 has a balanced mode and an ACG mode. In the balanced mode, an analog audio data is amplified by an amplifier 8, a negative-phase data of the analog audio data is amplified by an amplifier 9, and the amplified analog audio data and the amplified negative-phase data are mixed so as to be output. In the ACG mode, the analog audio data is amplified by the amplifier 8 and ground is maintained by the amplifier 9. The CPU 2 decreases volume of the analog audio data that is output in the balanced mode compared with volume of the analog audio data that is output in the ACG mode.

Abstract: To realize active control ground that sets inverted output of an amplification circuit to ground with simple configuration. A DAP 1 comprises a positive side DAC 7 that D/A-converts digital audio data into analog audio data, a positive side amplification circuit 9 that amplifies the analog audio data that the DAC 7 D/A-converts, a negative side DAC 8 that D/A-converts the digital audio data into the analog audio data, and a negative side amplification circuit 10 that amplifies the analog audio data that the DAC 8 D/A-converts, and a CPU 2. The CPU 2 mutes the DAC 8 in case of an ACG mode that sets output of the amplification circuit 10 to ground.

Abstract: The pulse width modulator includes a subtraction unit configured to perform subtraction between an m value digital signal and a pulse width modulation signal; a feedforward filter unit configured such that a ?? modulator to which an output signal of the subtraction unit is input and which includes integrators of a second order or higher is in cascade connection, and configured to operate with a sampling frequency FS; a product-sum computing unit configured to operate with a sampling frequency (FS/n) (n: an integer of two or more) to perform product-sum computing of an output signal of each integrator of the feedforward filter unit; and a pulse width modulation unit configured to operate with the sampling frequency (FS/n) to perform pulse width modulation of an output signal of the product-sum computing unit to output a pulse width modulation signal.

Abstract: To reduce signal output and wiring to a D/A converter (DAC). A DAP 1 comprises a DAC 7 that D/A-converts LR 2 channels digital audio data into LR 2 channels analog audio data, an amplification circuit 9 that amplifies the LR 2 channels analog audio data that the DAC 7 D/A-converts, a DAC 8 that D/A-converts the LR 2 channels digital audio data into the LR 2 channels analog audio data, and an amplification circuit 10 that amplifies inverted LR 2 channels analog audio data that the LR 2 channels analog audio data that the DAC 8 D/A-converts is inverted.

Abstract: To provide an effect circuit that can give round-shaped distortion effect to a music signal. An effect circuit 1 includes a input resistor R2 that is connected to a negative input terminal of an operational amplifier U1, a feedback resistor VR1 that is provided between a positive input terminal of the operational amplifier U1 and an output terminal of the operational amplifier U1, zener diodes D1 and D2 in each of which cathodes are connected and that are provided in parallel with the feedback resistor VR1, and diodes D3 and D4 that are connected in parallel so that each cathode and each anode are connected and are provided between cathodes of the zener diodes D1 and D2.

Abstract: Provided is a circuit which can correct an output state in real time and reduce influences of distortion/noise components generated by a delay device. A signal modulation circuit includes a subtractor, an integrator, a phase inverting circuit, a DFF for while inserting a zero level at timing synchronous with the clock signal, delaying and quantizing the signal, a ternary signal generating circuit for generating a ternary signal for selectively driving a load connected to a single power supply into ternary conductive states including a positive current on-state, a negative current on-state, and an off-state, a driver circuit for generating a driving signal for driving a load, and a feedback circuit for feeding back the driving signal from the driver circuit to the input signal.