Abstract: Processing circuitry is provided for processing signals received from, for example, sense coils forming part of a position encoder used to encode the relative positions of two relatively movable members. The position encoder is such that each of the plurality of signals from the sense coils varies sinusoidally with the relative position of the members but out of phase with respect to each other. The processing circuitry comprises mixers for multiplying each of the received signals with one of a corresponding plurality of periodic time varying signals, each having the same predetermined period and a different predetermined phase, and an adder for adding the signals from the mixers. The phase of the mixing signals are chosen so that the output signals from the adder contains a single periodic component having the predetermined period whose phase varies with the relative position of the two members.

Abstract: Processing circuitry is provided for processing signals received from, for example, sense coils forming part of a position encoder used to encode the relative positions of two relatively moveable members. The position encoder is such that each of the plurality of signals from the sense coils varies sinusoidally with the relative position of the members but out of phase with respect to each other. The processing circuitry comprises mixers for multiplying each of the received signals with one of a corresponding plurality of periodic time varying signals, each having the same predetermined period and a different predetermined phase, and an adder for adding the signals from the mixers. The phase of the mixing signals are chosen so that the output signals from the adder contains a single periodic component having the predetermined period whose phase varies with the relative position of the two members.

Abstract: A low cost x-y digitising system is provided for use in consumer electronic devices, such as portable digital assistants, mobile telephones, web browsers and the like. The digitiser includes a resonant stylus, an excitation winding for energising the resonant stylus and a set of sensor windings for sensing the signal generated by the stylus, from which the x-y position of the stylus is determined.

Abstract: Processing circuitry is provided for processing signals received from, for example, sense coils forming part of a position encoder used to encode the relative positions of two relatively moveable members. The position encoder is such that each of the plurality of signals from the sense coils varies sinusoidally with the relative position of the members but out of phase with respect to each other. The processing circuitry comprises mixers for multiplying each of the received signals with one of a corresponding plurality of periodic time varying signals, each having the same predetermined period and a different predetermined phase, and an adder for adding the signals from the mixers. The phase of the mixing signals are chosen so that the output signals from the adder contains a single periodic component having the predetermined period whose phase varies with the relative position of the two members.

Abstract: A low cost x-y digitising system is provided for use in consumer electronic devices, such as portable digital assistants, mobile telephones, web browsers and the like. The digitiser includes a resonant stylus, an excitation winding for energising the resonant stylus and a set of sensor windings for sensing the signal generated by the stylus, from which the x-y position of the stylus is determined.

Abstract: A position encoder is provided for indicating the relative position between first and second relatively movable members. One of the members carries a multi-pole magnetic scale which generates a magnetic field whose magnitude and direction vary with position and the other member carries at least one sense conductor. A saturable magnetic element is located in the positionally varying magnetic field of the magnetic scale and an excitation winding is provided which, when energized, generates a magnetic filed which interacts with the positionally varying magnetic field to cause different portions of the saturable magnetic element to saturate and desaturate at different times. The arrangement of the sense conductor is such that as the magnetic element is driven into and out of saturation, it outputs a signal which is indicative of the position of the magnetic scale relative to the sense conductor.

Abstract: In a linear position encoder, a support is provided upon which a pair of phase quadrature windings are mounted. The windings are arranged to have a sinusoidal magnetic sensitivity characteristic along the length of the support. Mounted on a movable element there is a resonant circuit including a coil and capacitor that can magnetically couple with the windings. When the circuit is excited, it induces currents in the windings that are dependent upon the position of the circuit within a period T.sub.s of the windings. An excitation and processing unit is provided to energize the circuit and to process the signals induced in the windings. The encoder may in a variation, measure rotational or radial position instead of translation.