Abstract: A motion estimation system includes a head motion detection unit, a mobile body motion detection unit, and a movement estimation unit. The head motion detection unit is worn on an occupant in a mobile body, and detects a motion of a head of the occupant. The mobile body motion detection unit detects a motion of the mobile body. The movement estimation unit obtains the motion of the head of the occupant and the motion of the mobile body, and estimates a movement of the head of the occupant made by the occupant according to a difference between the motion of the head of the occupant and the motion of the mobile body.

Abstract: In a communication system, nodes are coupled to a transmission path in a bus topology. The nodes communicate with each other via the transmission path using communication signals that have a communication frequency and are synchronized with a power supply signal. Each of the nodes includes a coupling portion that transmits and receives the communication signal and the power supply signal using electromagnetic induction in non-contact with the transmission path. Each of the nodes determines whether a collision of the communication signals occurs on the transmission path based on a voltage level of a signal that has the communication frequency and is induced at the coupling portion.

Abstract: In a master apparatus, a reference device generates a reference signal, a power feeding signal generation portion divides or multiples a frequency of the reference signal to generate a power feeding signal, a first communication carrier generation portion divides or multiples the frequency of the reference signal to generate a first communication carrier, a communication signal generation portion generates a communication signal, and a superimposition portion superimposes the communication signal on the power feeding signal.

Abstract: In a master apparatus, a reference device generates a reference signal, a power feeding signal generation portion divides or multiples a frequency of the reference signal to generate a power feeding signal, a first communication carrier generation portion divides or multiples the frequency of the reference signal to generate a first communication carrier, a communication signal generation portion generates a communication signal, and a superimposition portion superimposes the communication signal on the power feeding signal.

Abstract: In a communication system, nodes are coupled to a transmission path in a bus topology. The nodes communicate with each other via the transmission path using communication signals that have a communication frequency and are synchronized with a power supply signal. Each of the nodes includes a coupling portion that transmits and receives the communication signal and the power supply signal using electromagnetic induction in non-contact with the transmission path. Each of the nodes determines whether a collision of the communication signals occurs on the transmission path based on a voltage level of a signal that has the communication frequency and is induced at the coupling portion.

Abstract: A communication system includes: a master device; and slave devices communicating with the master device via a transmission line. The master device includes: an electric power supply unit for outputting an electric power supply signal having one specific frequency to the transmission line; a master communication unit for communicating with each slave device through a communication signal; and an electric power supply frequency setting unit for setting the one specific frequency. Each slave device includes: an electric power supply signal input and output unit for retrieving the electric power supply signal having a set frequency from the transmission line; a communication signal input and output unit for receiving and transmitting the communication signal to the transmission line; a slave communication unit for communicating with the master device through the communication signal; and a power source for energizing the slave communication unit according to the electric power supply signal.

Abstract: An amplifier comprises an input terminal that inputs an AC voltage signal; an amplifying unit having a transistor for amplifying the input AC voltage signal; a current detecting unit connected internally of said amplifying unit; and a control-current source controlled by said current detecting unit that drives an input stage of the transistor.

Abstract: An amplifier comprises an input terminal that inputs an AC voltage signal; an amplifying unit having a transistor for amplifying the input AC voltage signal; a current detecting unit connected internally of said amplifying unit; and a control-current source controlled by said current detecting unit that drives an input stage of the transistor.