Abstract: A preamplifier amplifies signals input to first and second input terminals. A first switching circuit receives first and second input signals and respectively outputs those signals to the first and second input terminals. A switched capacitor circuit samples two signals amplified by the preamplifier. An integration circuit includes a fully differential operational amplifier outputting amplifying differential signals input between third and fourth input terminals between second and first output terminals, and first and second integration capacitors. A second switching circuit switches a connection relationship between the switched capacitor circuit, and the first and second integration capacitors. A third switching circuit switches a connection relationship between the first and second integration capacitors, and third and fourth output terminals.

Abstract: A preamplifier amplifies signals input to first and second input terminals. A first switching circuit receives first and second input signals and respectively outputs those signals to the first and second input terminals. A switched capacitor circuit samples two signals amplified by the preamplifier. An integration circuit includes a fully differential operational amplifier outputting amplifying differential signals input between third and fourth input terminals between second and first output terminals, and first and second integration capacitors. A second switching circuit switches a connection relationship between the switched capacitor circuit, and the first and second integration capacitors. A third switching circuit switches a connection relationship between the first and second integration capacitors, and third and fourth output terminals.

Abstract: A preamplifier amplifies signals input to first and second input terminals. A first switching circuit receives first and second input signals and outputs those to the first and second input terminals. A switched capacitor circuit samples two signals amplified by the preamplifier. Differential signals sampled by the switched capacitor circuit are respectively input to third and fourth input terminals of an integration circuit, and the integration circuit outputs differential signals obtained by those input signals to first and second output terminals. A second switching circuit switches a connection relationship between the switched capacitor circuit and the integration circuit. Each time the cycle changes, the first and second switching circuits switch the connection relationships to cause the signals amplified by the preamplifier to be sampled by double correlation sampling.

Abstract: An object is to respectively excite transmission coils with different voltages using a single power supply with low power consumption in an electromagnetic induction type encoder. A detection head of an encoder includes a voltage adjustment circuit and a plurality of excitation circuits. The excitation circuit includes a resonant circuit that includes a driving capacitor and a transmission coil connected in series and generates an alternate-current magnetic field inducing currents in scale coils disposed in a plurality of scale tracks on a scale by connecting both ends of the resonant circuit in a state in which the driving capacitor is charged. The voltage adjustment circuit includes a first transformer capacitor and controls a charging voltage of the driving capacitor in a single excitation circuit using the charged first transformer capacitor.

Abstract: A reference voltage generator circuit generates a reference voltage corresponding to a power supply voltage. A current/voltage converter circuit converts a photocurrent output by a photoreceiver into voltage, and outputs a voltage obtained by adding the converted voltage and the reference voltage. A sample and hold circuit holds a voltage of a capacitor in response to a sample and hold signal, the capacitor having the voltage input at one end and the reference voltage input at another end. An amplifier circuit outputs an output signal where a voltage held by the sample and hold circuit is amplified with the reference voltage as a reference.

Abstract: An object is to respectively excite transmission coils with different voltages using a single power supply with low power consumption in an electromagnetic induction type encoder. A detection head of an encoder includes a voltage adjustment circuit and a plurality of excitation circuits. The excitation circuit includes a resonant circuit that includes a driving capacitor and a transmission coil connected in series and generates an alternate-current magnetic field inducing currents in scale coils disposed in a plurality of scale tracks on a scale by connecting both ends of the resonant circuit in a state in which the driving capacitor is charged. The voltage adjustment circuit includes a first transformer capacitor and controls a charging voltage of the driving capacitor in a single excitation circuit using the charged first transformer capacitor.

Abstract: The electromagnetic induction type position detector includes a scale having a plurality of gradation coils, a head having a transmission unit and a reception unit, and a control unit. Each of the plurality of graduation coils includes a transmission graduation arranged with a pitch L1, a reception graduation arranged with a pitch L0 different from the pitch L1, and a connection unit. The transmission unit includes three transmission coil groups that are constituted by pluralities of transmission coils, each being arranged with a pitch L1, and that are arranged such that adjacent transmission coil groups have a phase difference. The reception unit includes three reception coil groups that are constituted by pluralities of reception coils, each being arranged with a pitch L0, and that are arranged such that adjacent reception coil groups have a phase difference identical to the phase difference of the three transmission coil groups.

Abstract: The electromagnetic induction type position detector includes a scale having a plurality of gradation coils, a head having a transmission unit and a reception unit, and a control unit. Each of the plurality of graduation coils includes a transmission graduation arranged with a pitch L1, a reception graduation arranged with a pitch L0 different from the pitch L1, and a connection unit. The transmission unit includes three transmission coil groups that are constituted by pluralities of transmission coils, each being arranged with a pitch L1, and that are arranged such that adjacent transmission coil groups have a phase difference. The reception unit includes three reception coil groups that are constituted by pluralities of reception coils, each being arranged with a pitch L0, and that are arranged such that adjacent reception coil groups have a phase difference identical to the phase difference of the three transmission coil groups.

Abstract: A reference voltage generator circuit generates a reference voltage corresponding to a power supply voltage. A current/voltage converter circuit converts a photocurrent output by a photoreceiver into voltage, and outputs a voltage obtained by adding the converted voltage and the reference voltage. A sample and hold circuit holds a voltage of a capacitor in response to a sample and hold signal, the capacitor having the voltage input at one end and the reference voltage input at another end. An amplifier circuit outputs an output signal where a voltage held by the sample and hold circuit is amplified with the reference voltage as a reference.

Abstract: A photoelectric encoder according to the present invention comprises a light-receiving unit including: a first and second light-receiving element column; and a light-blocking layer configured from a light-blocking portion and a light-transmitting portion, the first and second light-receiving element columns being disposed staggered in a second direction such that an arrangement pattern of light-receiving elements in the first and second light-receiving element columns has a pitch which is the same in a first direction and a phase which differs in the first direction, and the light-transmitting portion on the light-receiving surface of the light-receiving element in the first light-receiving element column and the light-transmitting portion on the light-receiving surface of the light-receiving element in the second light-receiving element column being formed so as not to overlap each other when staggered in the second direction.

Abstract: An absolute rotary encoder comprises a rotor having a bore passing through the center thereof to receive a shaft therein and arranged rotatably about the shaft and opposite a stator. Tracks are arranged concentrically on the rotor to form a track group. A transmitting winding group is arranged on the stator as capable of flux coupling with the track group. A receiving winding group is arranged on the stator as capable of flux coupling with the track group. Each track in the track group comprises a flux coupling winding that includes linear arc portions having first and second radii and arranged alternately on the rotor and has the shape of a ring continuous about the shaft. At least two tracks in the track group have the linear arc portions different in number from each other.

Abstract: An absolute rotary encoder comprises a rotor having a bore passing through the center thereof to receive a shaft therein and arranged rotatably about the shaft and opposite a stator. Tracks are arranged concentrically on the rotor to form a track group. A transmitting winding group is arranged on the stator as capable of flux coupling with the track group. A receiving winding group is arranged on the stator as capable of flux coupling with the track group. Each track in the track group comprises a flux coupling winding that includes linear arc portions having first and second radii and arranged alternately on the rotor and has the shape of a ring continuous about the shaft. At least two tracks in the track group have the linear arc portions different in number from each other.