All The Claims

1. A subtractor circuit comprising:
a first signal input to receive a first signal;
a first signal path coupled to the first signal input;
a second signal input to receive a second signal;
a second signal path coupled to the second signal input; and
an operational amplifier comprising:
a first input coupled to the first signal path to receive the first signal;
a second input coupled to the second signal path to receive the second signal;
a first output that provides a subtractor signal output that is a function of a difference between the first signal and the second signal; and
a second output connected to the first input via a feedback path that provides the subtractor signal output as a feedback signal to the first input.
2. The circuit of claim 1, wherein the feedback path comprises a direct connection from the second output to the first input as a current feedback path.
3. The circuit of claim 1, further comprising a cascade circuit coupled to the first output of the operational amplifier that receives the subtractor signal output.
4. The circuit of claim 1, further comprising a power detector having an input that receives a radio-frequency signal and having an output coupled to the first signal input that provides the first signal dependent on a power level of the radio-frequency signal.
5. The circuit of claim 4, further comprising a second power detector having an output coupled to the second signal input that provides the second signal as a reference signal having a constant level.
6. The circuit of claim 5, wherein the first signal path comprises a first resistor and a second resistor, connected in series and having substantially equal resistance.
7. The circuit of claim 1, wherein the feedback path comprises a current-controlled voltage source.
8. The circuit of claim 7, wherein the current-controlled voltage sources comprises a resistor.
9. The circuit of claim 1, wherein the feedback path comprises a current mirror and a current-controlled voltage source, wherein the current-controlled voltage source is connected to the first output of the operational amplifier via the current mirror.
10. A subtractor circuit comprising:
a first power detector to receive a radio frequency signal and generate a first signal having a first voltage level according to a power level of the radio frequency signal;
a second power detector to generate a second signal having a constant voltage level according to a ground reference value; and
a power amplifier comprising:
a first input to receive the first signal and a feedback signal;
a second input to receive the second signal;
a first output to generate the feedback signal according to the first signal and the second signal; and
a second output to generate a differential output signal according to the first signal and the second signal.
11. The circuit of claim 10, wherein the first voltage level is about 0.5 to 2 volts.
12. The circuit of claim 11, wherein the constant voltage level is about 0.5 and a differential voltage of the first signal and the second signal is about 0.0 to 1.5 volts.
13. The circuit of claim 10, wherein the feedback signal has a current value proportional to a differential voltage of the first signal and the second signal.
14. The circuit of claim 10, wherein the differential output signal has a current proportional to a differential voltage of the first signal and the second signal.
15. The circuit of claim 14, further comprising a current conversion circuit to receive the differential output signal and convert the differential output signal into an output voltage signal, wherein the output voltage signal has a voltage level proportional to the differential voltage of the first signal and the second signal.
16. The circuit of claim 10, wherein the feedback signal and the differential output signal are as synchronous signal sources.
17. The circuit of claim 10, wherein the feedback signal has a constant voltage level and the differential output signal has a varying voltage level.

The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.

1. A sensor element comprising a contamination-resistant coating on at least a portion thereof, the coating comprising gamma alumina and magnesium titanate.
2. The element of claim 1, wherein the coating has a thickness of about 50 to about 300 microns.
3. The element of claim 1, wherein the coating has a porosity of about 10 to about 55 percent.
4. The element of claim 1, wherein the portion of the sensor element is a substrate having a plurality of edges, and wherein the coating does not touch or cover at least one of the edges.
5. The element of claim 4, wherein the substrate is a surface of an electrolyte foil, and the surface has an exposed portion that is not covered by the coating.
6. The element of claim 5, wherein the coating at least partially covers an electrode.
7. The element of claim 1, wherein the portion of the sensor element is a protective layer comprising at least one of zirconium oxide, aluminum oxide, titanium oxide, magnesium oxide, and a combination thereof.
8. The element of claim 1, wherein the coating further comprises boehmite alumina.
9. The element of claim 8, wherein the coating has a thickness of about 50 to about 300 microns.
10. A sensor element comprising a contamination-resistant coating on at least a portion thereof, the coating comprising gamma alumina, magnesium titanate, and boehmite alumina.
11. A method of making a contamination-resistant sensor element:
mixing gamma alumina and magnesium titanate to form a mixture;
applying the mixture to at least a portion of a sensor element; and
temperature treating the mixture to form a contamination-resistant coating on the sensor element.
12. The method of claim 11, wherein the mixture further comprises boehmite alumina.
13. The method of claim 12, wherein the mixture comprises about 20 to about 40 percent by weight gamma alumina, about 0.01 to about 8 percent by weight magnesium titanate, and about 1 to about 20 percent by weight boehmite alumina.
14. The method of claim 12, wherein the mixture further comprises a low temperature binder.
15. The method of claim 14, wherein the low-temperature binder comprises at least one of hydroxyethyl cellulose, polyvinyl alcohol, polyvinyl pyrrolidone, polyvinyl acetate, polyacrylic resins, and a combination thereof.
16. The method of claim 14, wherein the low temperature binder comprises polyvinyl alcohol.
17. The method of claim 14, wherein the mixture comprises about 20 to about 40 percent by weight gamma alumina, about 0.01 to about 8 percent by weight magnesium titanate, about 1 to about 20 percent by weight boehmite alumina, and about 0.5 to about 10 percent by weight low temperature binder.
18. The method of claim 17, wherein the contamination-resistant coating has a thickness of about 50 to about 300 microns and a porosity of about 10 to about 55 percent.
19. The method of claim 12, wherein the portion of the element is a substrate having a plurality of edges, and the coating does not touch or cover at least one of the edges.
20. The method of claim 19, wherein the substrate is a surface of an electrolyte foil, and the surface has an exposed portion that is not covered by the coating.
21. The method of claim 20, wherein an adhesive is used to secure the coating to the substrate, and the adhesive adheres to at least a portion of the exposed portion and at least a portion of the coating.
22. The method of claim 21, wherein the electrolyte foil has a side, and the adhesive adheres to at least a portion of the side.
23. The method of claim 22, further comprising a protective layer comprising at least one of zirconium oxide, aluminum oxide, titanium oxide, magnesium oxide, and a combination thereof, the protective layer being positioned between the coating and the foil.
24. The method of claim 12, wherein the portion of the sensor element is a protective layer.
25. The method of claim 24, wherein the protective layer is mechanically structured to improve adhesion between the coating and the sensor element.
26. The method of claim 25, wherein the protective layer comprises at least one of zirconium oxide, aluminum oxide, titanium oxide, magnesium oxide, and a combination thereof.
27. The method of claim 12, wherein the sensor element is a part of an automotive exhaust gas sensor.
28. The method of claim 11, wherein the mixture is temperature-treated by drying the mixture at room temperature for at least about 10 minutes and then heating the mixture in the range of about 250\xb0 C. to about 1200\xb0 C. for about 30 minutes to about 8 hours.
29. A sensor element comprising:
a substrate having a plurality of edges;
a contamination-resistant coating comprising gamma alumina and magnesium titanate applied to at least a portion of the substrate such that the coating does not touch or cover at least one of the edges, thereby leaving an exposed part of the substrate not covered by the coating; and
an adhesive adhering to at least a portion of the exposed part and at least a portion of the coating to secure the coating to the substrate.

1. A control device for controlling a two-way linear solenoid valve comprising a pressure regulating port which communicates with a hydraulic circuit side, a drain port which communicates with a drain side, a plunger which controls the state of communication between the pressure regulating port and drain port, and a coil which drives the plunger in accordance with an exciting current, the control device comprising:
a current generator which supplies the coil with the exciting current corresponding to a duty signal; and
a microcomputer programmed to:
determine whether or not a preset foreign matter removal starting condition for removing foreign matter accumulated in the ports has been established;
set a variation pattern for a current command value in the form of a rectangular wave having a preset maximum current command value and a preset minimum current command value, when the foreign matter removal starting condition is established, and subsequently transmit to the current generator a first duty signal corresponding to the maximum current command value and a second duty signal corresponding to the minimum current command value;
determine whether or not a preset foreign matter removal completion condition has been established; and
terminate the setting of the rectangular wave variation pattern when the foreign matter removal completion condition is established.
2. The control device as defined in claim 1, wherein the linear solenoid valve comprises a seal member around a drain port side opening portion of the pressure regulating port, to and from which an end face of the plunger is connected and disconnected,
the plunger performing a reciprocal motion in the axial direction thereof according to the setting of the variation pattern of the rectangular wave form current command value, whereby the seal member and the end face of the plunger are connected and disconnected,
the pressure regulating port and the drain port communicating with each other or being blocked from each other in accordance with the connection or disconnection.
3. The control device as defined in claim 2, wherein the maximum current command value is a value at which the end face of the plunger is removed from the seal member by a predetermined amount enabling the removal of foreign matter, and
wherein the minimum current command value is a value at which the end face of the plunger contacts the seal member.
4. The control device as defined in claim 1, wherein the two-way linear solenoid valve is used in a transmission connected to an engine,
the control device comprises means for detecting start-up of the engine, and
the foreign matter removal starting condition is the start-up of the engine.
5. The control device as defined in claim 4, wherein the foreign matter removal completion condition is the elapse of a predetermined amount of time following the start-up of the engine.
6. The control device as defined in claim 4, wherein the control device comprises means for detecting an operating range of the transmission, and
wherein the foreign matter removal completion condition is established when the operating range of the transmission is in a traveling range, in which the transmission outputs a rotation of the engine.
7. The control device as defined in claim 4, wherein the control device comprises a sensor which detects an output rotation speed of the transmission, and
wherein the foreign matter removal completion condition is established when the output rotation speed of the transmission is equal to or greater than a predetermined value.
8. The control device as defined in claim 1, wherein the two-way linear solenoid valve is used in a belt continuously variable transmission connected to the engine,
the control device comprises a sensor which detects a primary pressure acting on a primary pulley of the continuously variable transmission, and
the foreign matter removal starting condition is a reduction in the primary pressure below a target value.
9. The control device as defined in claim 1, wherein the two-way linear solenoid valve is used in a belt continuously variable transmission connected to the engine,
the control device comprises a sensor which detects a secondary pressure acting on a secondary pulley of the continuously variable transmission, and
the foreign matter removal starting condition is a reduction in the secondary pressure below a target value.
10. A control device for controlling a two-way linear solenoid valve comprising a pressure regulating port which communicates with a hydraulic circuit side, a drain port which communicates with a drain side, a plunger which controls the state of communication between the pressure regulating port and drain port, and a coil which drives the plunger in accordance with an exciting current, the control device comprising:
current generating means for supplying the coil with the exciting current corresponding to a duty signal;
determination means for determining whether or not a preset foreign matter removal starting condition for removing foreign matter accumulated in the ports has been established;
setting means for setting a variation pattern for a current command value in the form of a rectangular wave having a preset maximum current command value and a preset minimum current command value, when the foreign matter removal starting condition is established,
transmission means for transmitting to the current generating means a first duty signal corresponding to the maximum current command value and a second duty signal corresponding to the minimum current command value;
determination means for determining whether or not a preset foreign matter removal completion condition has been established; and
termination means for terminating the setting of the rectangular wave variation pattern when the foreign matter removal completion condition is established.
11. A control method for controlling a two-way linear solenoid valve comprising a pressure regulating port which communicates with a hydraulic circuit side, a drain port which communicates with a drain side, a plunger which controls the state of communication between the pressure regulating port and drain port, a current generator which supplies a coil with an exciting current corresponding to a duty signal, and the coil which drives the plunger in accordance with the exciting current, the control method comprising the steps of:
determining whether or not a preset foreign matter removal starting condition for removing foreign matter accumulated in the ports has been established;
setting a variation pattern for a current command value in the form of a rectangular wave having a preset maximum current command value and a preset minimum current command value, when the foreign matter removal starting condition is established, and subsequently transmitting to the current generator a first duty signal corresponding to the maximum current command value and a second duty signal corresponding to the minimum current command value;
determining whether or not a preset foreign matter removal completion condition has been established; and
terminating the setting of the rectangular wave variation pattern when the foreign matter removal completion condition is established.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.

I claim:

1. An anti-mine unit for digging up, exposing and exploding mines in a minefield, comprising:
a front beam, a rear beam, and two opposing side beams defining a rectangular frame;
mounting means normal to the rear beam for mounting the rectangular frame to a prime mover so that the frame extends horizontally in front of the prime mover;
a plurality of digging cables suspended from the front beam adapted for digging into a surface of the minefield, each cable being independently suspended;
a plurality of drag cables suspended from the front beam adapted for dragging over the surface of the minefield, each dragging cable being independently suspended;
a plurality of curtain cables suspended from the rear beam and the two opposing side beams;
a first pair of deflector cables and a second pair of deflector cables mounted to opposite ends of the rear beam, respectively, the deflector cables being adapted for deflecting unexploded mines from a path of the prime mover.
2. The anti-mine unit of claim 1, further comprising a top plate affixed to said rectangular frame and covering an opening defined by said rectangular frame, said top plate and said curtain cables minimizing blast damage from mines exploded by the anti-mine unit.
3. The anti-mine unit of claim 2, wherein said top plate has a plurality of holes defined therein adapted for passing a flexible element therethrough for lifting said drag cables..
4. The anti-mine unit of claim 1, wherein each said digging cable further comprises an end cap having a digger blade extending therefrom adapted for penetrating the surface of the minefield attached to an end of the digging cable.
5. The anti-mine unit of claim 4, wherein each said digging cable further comprises a shallow ground engaging blade attached to said end cap about 180 opposite said digger blade.
6. The anti-mine unit of claim 1, wherein each said digging cable comprises a three inch diameter steel cable.
7. The anti-mine unit of claim 6, wherein of said drag cables further comprises a plurality of sleeves disposed thereon, each of said sleeves having a plurality of ground engaging blades extending therefrom adapted for dragging across a minefield and detonating shallow mines..
8. The anti-mine unit of claim 7, wherein each of said drag cables further comprises a grass blade attached to said sleeves adapted for penetrating tall grass.
9. The anti-mine unit of claim 1, wherein each of said drag cables comprises two inch diameter steel cable.
10. The anti-mine unit of claim 1, wherein said curtain cables comprise two inch diameter steel cables spaced five said cables per ten inches of beam.
11. The anti-mine unit of claim 1, wherein further comprising an elongated rod attached to each said side beam, said elongated rod limiting outward rotation of said curtain cables to 70 from vertical.
12. The anti-mine unit of claim 1, wherein said each said deflector cable comprises three inch diameter steel cable.
13. The anti-mine unit of claim 1, wherein each said deflector cable further comprises an end cap having a plow blade attached thereto.
14. The anti-mine unit of claim 13, wherein each said deflector cable is bolted to an adjacent said deflector cable in the pair of deflector cables at the plow blade end of said deflector cables.
15. The anti-mine unit of claim 1, wherein said frame further comprises:
right and left vertical rear beams extending normal to said rear beam and to said opposing side beams;
a lower rear beam extending between said right and left vertical rear beams parallel to said rear beam; and
lower left and right side beams extending diagonally between said front beam and said lower rear beam, the opposing side beams lower right and left side beams, and right and left vertical rear beams defining rigid triangular supports maintaining said front beam in an elevated position.
16. The anti-mine unit of claim 1, further comprising:
a digging cable support beam extending between the two opposing side beams;
a drag cable support beam extending between the two opposing side beams; and
a plurality of lift cables extending between said digging cable support beam and said digging cables, and between said drag cable support beam and said drag cables, for preventing movement of said digging and drag cables forward of said front beam.
17. The anti-mine unit of claim 1, further comprising a plurality of digging cable shackles and a plurality of drag cables shackles attached in alternating fashion to said front beam, said digging cable shackles being radially staggered from said drag cable shackles, one said digging cable being removably attached to each said digging cable shackle, one said digging cable and one said drag cable being removably attached to each said drag cable shackle, whereby said digging cables and said drag cables are easily removed for repair and replacement.
18. The anti-mine unit of claim 1, further comprising a plurality of wire cutters attached to said front beam. 29