Remote sensor device

A system comprising:

• a self-oscillating remote sensor device comprising:
• a delay-line sensor system including at least one delay-line and at least one sensor element;
• an oscillator control circuitry;
• and
• a frequency selection impedance connecting the delay-line sensor system and the oscillator control circuitry and presenting an impedance to the delay-line sensor system;
• wherein the oscillator control circuitry includes an amplifier, a non-linear amplitude control element (N-LACE) and a driver;
• and
• a first conductive object,
• the at least one sensor element of the self-oscillating remote sensor device being arranged in proximity with the first conductive object so as to permit sensing of a parameter thereof.

A system comprising:

• a self-oscillating remote sensor device comprising:
• a delay-line sensor system including at least one delay-line and at least one sensor element;
• an oscillator control circuitry;
• and
• a frequency selection impedance connecting the delay-line sensor system and the oscillator control circuitry and presenting an impedance to the delay-line sensor system;
• wherein the oscillator control circuitry includes an amplifier, a non-linear amplitude control element (N-LACE) and a driver, and
• an arrangement to be sensed which includes a first conductive object and a second object;
• wherein the at least one sensor element of the self-oscillating remote sensor device is arranged in proximity to the arrangement to be sensed so that a parameter of the first conductive object relative to the second object may be sensed.

A closed loop control arrangement comprising:

• a remote sensor device comprising:
• a delay-line sensor system including at least one delay-line and at least one sensor element;
• an oscillator control circuitry;
• and
• a frequency selection impedance connecting the delay-line sensor system and the oscillator control circuitry and presenting an impedance to the delay-line sensor system;
• wherein the oscillator control circuitry includes an amplifier, a non-linear amplitude control element (N-LACE) and a driver;
• a system controller;
• and
• a system;
• wherein the remote sensor device is arranged to output remote sensor device (RSD) output signal to the system controller based upon at least one of a property, parameter or quantity of the system measured by the sensor element of the delay-line sensor system, and
• wherein the system controller is configured to provide a feedback control signal, to the system based upon the RSD output signal so as to control or modify the or a related property, parameter and/or quantity of the system.

A closed loop control arrangement comprising:

• a first system,
• a second system,
• a system controller, and
• a remote sensor device comprising:
• a delay-line sensor system including at least one delay-line and at least one sensor element;
• an oscillator control circuitry;
• and
• a frequency selection impedance connecting the delay-line sensor system and the oscillator control circuitry and presenting an impedance to the delay-line sensor system;
• wherein the oscillator control circuitry includes an amplifier, a non-linear amplitude control element (N-LACE) and a driver;
• wherein the remote sensor device is arranged to output a remote sensor device (RSD) output signal to the system controller based upon at least one of a first property, parameter or quantity of the first system measured or detected by the sensor element of the delay-line sensor system, and wherein the system controller is configured to provide a control signal to the second system based upon the RSD output signal so as to control or modify at least one of a second property, parameter or quantity of the second system.

A method of tracking a resonant mode in a remote sensor device, comprising:

• exciting a resonant mode of the remote sensor device;
• causing or allowing the resonance frequency of the resonant mode to change over time;
• and
• tracking the resonant mode as it changes over time, by configuring the oscillator control circuitry and frequency selection impedance to supply a unity gain and an overall control-loop phase shift of 360.n degrees (where n is an integer>=0) only over the range of frequencies which the resonant mode changes over time.