POSITION SENSOR WITH IMPROVED SIGNAL TO NOISE RATIO
First Claim
1. A sensor having a waveguide and measuring a position, the waveguide having a length, a waveguide circuit comprising at least the waveguide and a return conductor, the return conductor at least partially surrounding the waveguide over a major portion of the waveguide length, the return conductor connected with a circuit common, ground, or shield, the waveguide and return conductor enclosed within a housing.
0 Assignments
0 Petitions
Accused Products
Abstract
A magnetostrictive position sensor achieves an improved signal to noise ratio by implementing several electronic control features, including: enclosing a waveguide within an approximately tubular return conductor, adjusting the energy of an interrogation pulse and then clamping the waveguide, tracking the peak voltage of a sensed signal, cutting off the signal of a pickup during the time period outside of a signal time frame, adjusting the pass band of a filter based on an interrogation rate and waveguide length, zeroing and scaling a signal without digitizing the signal, and avoiding noise from an interrogation voltage generator.
-
Citations
19 Claims
- 1. A sensor having a waveguide and measuring a position, the waveguide having a length, a waveguide circuit comprising at least the waveguide and a return conductor, the return conductor at least partially surrounding the waveguide over a major portion of the waveguide length, the return conductor connected with a circuit common, ground, or shield, the waveguide and return conductor enclosed within a housing.
- 2. A sensor having a waveguide circuit, the waveguide circuit comprising a waveguide and a return conductor, first and second interrogation pulses applied to the waveguide circuit, a waveguide clamp capable of being enabled or disabled, the enabling of the waveguide clamp causing the waveguide and the return conductor to be connected together through an impedance of no greater than 50 ohms, the waveguide clamp being enabled after a leading edge of the first interrogation pulse, and the waveguide clamp disabled at a time before or coincident with a leading edge of the second interrogation pulse.
- 4. A sensor having a waveguide, the waveguide having a length, an interrogation pulse applied to the waveguide, an interrogation voltage having an amplitude, the interrogation voltage appearing across a capacitance, the interrogation voltage amplitude being adjustable, the interrogation voltage amplitude adjusted in relation to the length of the waveguide.
- 7. A sensor having a waveguide, an interrogation pulse applied to the waveguide, the interrogation pulse having a pulse width, a pickup proximate the waveguide and having electrical connections, a signal clamp device having a signal clamp input and connected across at least two of the pickup electrical connections during a signal clamp period, the signal clamp device being open or closed, the signal clamp device having a resistance of less than 100 ohms when closed, the signal clamp period coincident with at least a part of the interrogation pulse width.
-
10. A sensor having a waveguide and measuring a position, a strain wave traveling in the waveguide, a pickup proximate the waveguide and producing a signal pulse in response to the strain wave, a voltage adjusting circuit providing an adjusted signal pulse having an amplitude;
a voltage divider providing first and second setpoints coupled respectively with first and second comparators, the adjusted signal pulse being coupled with first and second comparators, the first and second comparators each having an output, the output of the first comparator coupled with a capacitance, a signal tracking voltage being developed across the capacitance, the signal tracking voltage increasing when the adjusted signal pulse amplitude exceeds the first setpoint, the voltage adjusting circuit being adjusted relative to the signal tracking voltage, the output of the second comparator transitioning between two voltages in response to a variation in the amplitude of the adjusted signal pulse above or below the second setpoint. - View Dependent Claims (19)
-
11. A sensor having a waveguide and measuring a position, the waveguide having a length, interrogation pulses applied to the waveguide at an interrogation frequency, the interrogation frequency being related to the waveguide length;
a switched capacitor filter having a switching frequency, the switching frequency related to the interrogation frequency or to the waveguide length.
Specification