Sensing apparatus and method
First Claim
1. A sensor for sensing a parameter and for providing a value representative of the parameter being sensed, the sensor comprising:
- an excitation winding;
a resonator;
a sensor winding electromagnetically coupled to the excitation winding via the resonator;
a signal generator operable to generate an excitation signal and arranged to apply the generated excitation signal to the excitation winding in order to generate a periodic electric signal in the sensor winding indicative of the value of the parameter to be measured by the sensor, wherein the excitation signal comprises a periodic carrier signal having a first frequency, which is operable to induce a resonant signal in the resonator, modulated by a periodic modulation signal having a second frequency, the first frequency being greater than the second frequency;
a demodulator operable to demodulate the electric signal generated in the sensor winding to obtain a signal at the second frequency; and
a signal processor operable to process said signal at the second frequency to determine a value representative of the parameter being measured.
11 Assignments
0 Petitions
Accused Products
Abstract
There is described a sensor comprising an excitation winding, a signal generator operable to generate an excitation signal and arranged to apply the generated excitation signal to the excitation winding, a sensor winding electromagnetically coupled to the excitation winding and a signal processor operable to process a periodic electric signal generated in the sensor winding when the excitation signal is applied to the excitation winding by the signal generator to determine a value of a sensed parameter. The excitation signal comprises a periodic carrier signal having a first frequency modulated by a periodic modulation signal having a second frequency, the first frequency being greater than the second frequency. In this way, the sensor is well suited to using digital processing techniques both to generate the excitation signal and to process the signal induced in the sensor windings. In an embodiment, the sensor is used to detect the relative position of two members. In other embodiments, the sensor is used to detect environmental factors such as temperature and humidity.
71 Citations
43 Claims
-
1. A sensor for sensing a parameter and for providing a value representative of the parameter being sensed, the sensor comprising:
-
an excitation winding; a resonator; a sensor winding electromagnetically coupled to the excitation winding via the resonator; a signal generator operable to generate an excitation signal and arranged to apply the generated excitation signal to the excitation winding in order to generate a periodic electric signal in the sensor winding indicative of the value of the parameter to be measured by the sensor, wherein the excitation signal comprises a periodic carrier signal having a first frequency, which is operable to induce a resonant signal in the resonator, modulated by a periodic modulation signal having a second frequency, the first frequency being greater than the second frequency; a demodulator operable to demodulate the electric signal generated in the sensor winding to obtain a signal at the second frequency; and a signal processor operable to process said signal at the second frequency to determine a value representative of the parameter being measured. - View Dependent Claims (3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 33, 34, 35)
-
-
2. A sensor for sensing a parameter and providing a value representative of the parameter being sensed, the sensor comprising:
-
an excitation winding; a sensor winding electromagnetically coupled to the excitation winding, the sensor winding forming part of a resonator; a signal generator operable to generate an excitation signal and arranged to apply the generated excitation signal to the excitation winding in order to generate a periodic electric signal in the sensor winding indicative of the value of the parameter to be measured by the sensor, wherein the excitation signal comprises a periodic carrier signal having a first frequency, which is operable to induce a resonant signal in the resonator, modulated by a periodic modulation signal having a second frequency, the first frequency being greater than the second frequency; a demodulator operable to demodulate the electric signal generated in the sensor winding to obtain a signal at the second frequency; and a signal processor operable to process said signal at the second frequency to determine the value representative of the parameter being measured. - View Dependent Claims (31, 32, 36, 37, 38, 39, 40, 41)
-
-
42. A position sensor comprising:
-
first and second members which are movable relative to each other along a measurement direction, the first member comprising first and second excitation windings and a sensor winding, and the second member comprising a resonator having a resonant frequency, wherein the electromagnetic coupling between the first excitation winding and the resonator varies with the relative position along the measurement direction of the first and second members in accordance with a first function and the electromagnetic coupling between the second excitation winding and the resonator varies with the relative position along the measurement direction of the first and second members in accordance with a second function different from the first function; an excitation circuit operable to generate first and second excitation signals and to apply the first and second excitation signals to the first and second excitation windings respectively, wherein in response to the first and second excitation signals being applied to said first and second excitation windings, there is generated in the sensor winding an electric signal corresponding to a combination of the first and second excitation signals weighted in accordance with the relative position of the first and second members along the measurement direction; and a signal processor operable to process the electric signal generated in the sensor winding to determine a value representative of the relative position along the measurement direction of the first and second members, wherein the first and second excitation signals comprise respective periodic carrier signals at a carrier frequency respectively modulated by first and second periodic modulation signals at a modulation frequency which is less than the carrier frequency, wherein the carrier frequency is substantially equal to the resonant frequency of the resonator, and wherein the first and second modulation signals have respective different phases.
-
-
43. A method of sensing a parameter, the method comprising:
-
applying an excitation signal to an excitation winding, thereby generating a signal in a sensor winding which is electromagnetically coupled to the excitation winding via a resonator; and processing said signal generated in the sensor winding to determine a value representative of the parameter being measured, wherein said exciting step comprises applying to the excitation winding a periodic carrier signal having a first frequency, which is operable to induce a resonant signal in the resonator, modulated by a periodic modulation signal having a second frequency, the first fiequency being greater than the second frequency, and wherein said processing step comprises demodulating the signal generated in the sensor winding to recover a signal at the second frequency.
-
Specification