An apparatus for detecting displacements of existing movable bodies made of ferromagnetic materials and magnetized by external magnetic fields, comprising a magnetic sensor disposed in the vicinity of the movable body for detecting change in the magnetic field caused by the motion of the body, and a processor for converting the outputs of the magnetic sensor into pulse signals.

The CPU of an electronic device generates a parameter for determining the amplitude of a serial data signal when it is output from an output device to a serial ATA bus. The parameter indicates a value that is needed to make the amplitude of the received serial data signal fall within a range, stipulated in serial ATA interface standards, when another electronic device receives the serial data signal. The parameter is generated in accordance with the cable length of the serial ATA bus designated by a cable length designation unit. The other electronic device is connected to the serial ATA bus.

An apparatus for tranmitting signals that can be broken down into at least one AC voltage component between a rotor and a stator from a sender unit to a receiver unit, with the help of annular coils, the coil windings of which form components of the sender or receiver unit, and which are arranged coaxially to the axis of rotation of the rotor and inductively coupled is to be developed so as to generate measured values that are associated with the rotational speed. According to the present invention, this is done in that at least one pair (13, 14; 15, 16) of annular coils is provided for supplying voltage to components on the rotor; in that at least one additional pair (17, 18) of annular coils is provided for the transmission of values that are to be measured on the rotor by means of a measuring system, from the rotor to the stator; in that a sensor element (43) for scanning the rotational speed of the rotor is provided; and in that a switching unit (44) is provided, with the help of which the measured values associated with the rotational speed of the rotor can be further processed or displayed (FIG. 3).

A magnetic encoder is disclosed that provides a uniform magnetic field which is time modulated at a carrier frequency and space modulated by a repetitive pattern of eddy-current conducting lands that move with variable motion. The time modulation is provided by driving an electrical coil in a resonant tank circuit. The space modulation provides areas of higher and lower magnetic field intensity which change in correspondence with the motion of the conducting lands. The intensity of the varying magnetic field is detected by a series connected pair of stationary coils that are positioned orthogonal to both the direction of the changing magnetic field and the direction of the motion of the conducting lands. The pair of stationary coils yield a differential electrical signal that is representative of the motion of the conducting lands.

A motion measurement device, more particularly designed for measurement of a rotation of a body around an axis. This device comprises a coded wheel drivably connected to said body for rotation and comprising a plurality of holes regularly distributed around said axis. Said holes are binary digits and for one digit is constituted by a simple hole passing through the wheel and, for the other, an open hole connected to the nearest edge of said wheel by a narrow slit. A sensor placed on the path of the holes and comprising two coils facing one another allows determination of the distance travelled by the moving body connected to said coded wheel. The speed and acceleration of the moving body can also be determined.