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: 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: In a protection device of a current amplifier circuit, to protect the current amplifier circuit against more high-speed operation than recovery time of a relay device and to protect operation of the current amplifier circuit in a wide range from low frequency side to high frequency side. A protection device 30 includes a detection circuit 32 that detects an abnormal current value of a current amplifier circuit 14 and outputs a first abnormality detection signal. The protection device 30 outputs a second abnormality detection signal continuously for predetermined time that starts from output timing of the first abnormality detection signal, turns down an input voltage value to the current amplifier circuit 14 at receiving timing of the second abnormality detection signal, and outputs a cutting command signal to a relay device 36 at the same timing.

Abstract: In a protection device of a current amplifier circuit, to protect the current amplifier circuit against more high-speed operation than recovery time of a relay device and to protect operation of the current amplifier circuit in a wide range from low frequency side to high frequency side. A protection device 30 includes a detection circuit 32 that detects an abnormal current value of a current amplifier circuit 14 and outputs a first abnormality detection signal. The protection device 30 outputs a second abnormality detection signal continuously for predetermined time that starts from output timing of the first abnormality detection signal, turns down an input voltage value to the current amplifier circuit 14 at receiving timing of the second abnormality detection signal, and outputs a cutting command signal to a relay device 36 at the same timing.

Abstract: A filter circuit that removes high-frequency components from an input signal, comprises: an operational amplifier; a first resistor connected between a non-inverting input terminal of the operational amplifier and an input signal source; a first capacitor connected to the non-inverting input terminal of the operational amplifier; a second resistor connected to the non-inverting input terminal of the operational amplifier; a third resistor connected between an inverting input terminal of the operational amplifier and the input signal source; a second capacitor connected between the inverting input terminal of the operational amplifier and an output terminal of the operational amplifier; and a fourth resistor connected to the inverting input terminal of the operational amplifier.

Abstract: A filter circuit that removes high-frequency components from an input signal, comprises: an operational amplifier; a first resistor connected between a non-inverting input terminal of the operational amplifier and an input signal source; a first capacitor connected to the non-inverting input terminal of the operational amplifier; a second resistor connected to the non-inverting input terminal of the operational amplifier; a third resistor connected between an inverting input terminal of the operational amplifier and the input signal source; a second capacitor connected between the inverting input terminal of the operational amplifier and an output terminal of the operational amplifier; and a fourth resistor connected to the inverting input terminal of the operational amplifier.

Abstract: A transmission signal processing device 10 includes a transmission signal data demultiplexing circuit RX for receiving multiplexed transmission signal data and demultiplexing the transmission signal data into video signal data and multi-channel audio signal data, a decoder circuit 100 for decoding the multi-channel audio signal data to obtain a plurality of multi-channel audio signal data including at least front center channel audio signal data, and a transmission signal data multiplexing circuit TX for multiplexing the video signal data and the front center channel audio signal data to obtain output transmission signal data.

Abstract: A transmission signal processing device 10 includes a transmission signal data demultiplexing circuit RX for receiving multiplexed transmission signal data and demultiplexing the transmission signal data into video signal data and multi-channel audio signal data, a decoder circuit 100 for decoding the multi-channel audio signal data to obtain a plurality of multi-channel audio signal data including at least front center channel audio signal data, and a transmission signal data multiplexing circuit TX for multiplexing the video signal data and the front center channel audio signal data to obtain output transmission signal data.