Abstract: [Object] To provide a mechanism that makes it possible to avoid inconveniences when the authentication process has abnormality. [Solution] A communication device comprising a control section configured to control each of a first process that achieves a prescribed function, and a second process that authenticates another communication device and that is different from the first process, wherein the control section performs control in such a manner that the second process is not performed in a case where abnormality is recognized.

Abstract: A system that prevents accomplishment of unauthorized communication between a terminal and a communication peer is provided. The system includes a measurement unit and a process execution unit. The measurement unit is arranged on at least one of the terminal or the communication peer to obtain a measured value corresponding to a distance between the terminal and the communication peer. The process execution unit determines whether the measured value is appropriate and controls actuation for authentication of the terminal through wireless communication performed between the terminal and the communication peer based on the determination result. The measurement unit executes a process for obtaining the measured value in a time period during which the communication for the authentication is not performed.

Abstract: An inexpensive communicator that forms an optimal communication electric field. A vehicle interior transmitter circuit includes a main transmitter circuit having a ferrite antenna for generating a main electric field. A closed loop antenna includes a basal end coil, inductively coupled to the main antenna, and a distal end coil, for generating an auxiliary electric field based on the inductive coupling.

Abstract: A rotation angle detector that is able to detect an absolute rotation angle of a detection body accurately and is able to reduce the installation space required. The rotation angle detector includes a first rotation angle detector connected to the detection body for generating a first detection signal having a cycle corresponding to the rotation of the detection body. The first rotation angle detector includes a first rotating body which is connected to the detection body and rotates together with the detection body. The detector includes a second rotation angle detector connected to the first rotation angle detector. The second rotation angle detector includes a second rotating body that rotates together with the first rotating body at a rate greater than that of the first rotating body, and generates a second detection signal having a cycle corresponding to the rotation of the second rotation body.

Abstract: A rotation angle detector that is able to detect an absolute rotation angle of a detection body accurately and is able to reduce the installation space required. The rotation angle detector includes a first rotation angle detector (15) connected to the detection body for generating a first detection signal having a cycle corresponding to the rotation of the detection body. The first rotation angle detector includes a first rotating body (13) which is connected to the detection body and rotates together with the detection body. The detector includes a second rotation angle detector (20) connected to the first rotation angle detector. The second rotation angle detector includes a second rotating body (16) that rotates together with the first rotating body at a speed greater than that of the first rotating body, and generates a second detection signal having a cycle corresponding to the rotation of the second rotating body.