Abstract: A semiconductor filter is provided to operate in conjunction with a differential pressure transducer. The filter receives a high and very low frequency static pressure attendant with a high frequency low dynamic pressure at one end, the filter operates to filter said high frequency dynamic pressure to provide only the static pressure at the other filter end. A differential transducer receives both dynamic and static pressure at one input port and receives said filtered static pressure at the other port where said transducer provides an output solely indicative of dynamic pressure. The filter in one embodiment has a series of etched channels directed from an input end to an output end. The channels are etched pores of extremely small diameter and operate to attenuate or filter the dynamic pressure.

Abstract: A pressure sensor including: a deflectable diaphragm including a substantially central boss and channel; and, an optical waveguide having first and second arms, wherein the first arm is substantially aligned with an edge of the boss and the second arm is substantially aligned with an edge of the channel.

Abstract: There is disclosed a high pressure sensing header which is relatively insensitive to mounting torque. Essentially the header consists of an outer torque isolating shell which has a “C” shaped cross section with the cylindrical shell surrounding an inner “H” section header. The inner “H” section header has a thick diaphragm and is surrounded by the torque isolating shell which is secured to the “H” section header at a peripheral flange of the “H” section header. In this manner when the header is installed, the installation force is absorbed by the outer shell and there is no installation force or torque exhibited by the inner “H” section which will respond only to stress due to pressure. The torque isolating shell also contains a top surface which has a counterbore which can accommodate a crush ring, and when the unit is installed, the crush ring is forced or crushed against an installation wall to enable the inner header to receive pressure without experiencing any significant installation force.

Abstract: It is an objective of the present invention to provide a highly sensitive optical pressure sensor that uses a Mach-Zehnder Interferometer to measure pressure. The pressure sensor comprises a deflectable diaphragm including a substantially central boss and channel and an optical waveguide having a first arm and a second arm, wherein the first arm is substantially aligned with an edge of the boss and the second arm is substantially aligned with an edge of the channel, and further wherein the first and second arms contain a periodic array of etched holes to improve the overall sensitivity of the pressure sensor. The pressure sensor further comprises a light source coupled to the optical waveguide for introducing light to the waveguide and a light detector coupled to the waveguide for detecting changes in the intensity of light. The change in light intensity is then correlated to an applied pressure.

Abstract: There is disclosed a high pressure sensing header which is relatively insensitive to mounting torque. Essentially the header consists of an outer torque isolating shell which has a “C” shaped cross section with the cylindrical shell surrounding an inner “H” section header. The inner “H” section header has a thick diaphragm and is surrounded by the torque isolating shell which is secured to the “H” section header at a peripheral flange of the “H” section header. In this manner when the header is installed, the installation force is absorbed by the outer shell and there is no installation force or torque exhibited by the inner “H” section which will respond only to stress due to pressure. The torque isolating shell also contains a top surface which has a counterbore which can accommodate a crush ring, and when the unit is installed, the crush ring is forced or crushed against an installation wall to enable the inner header to receive pressure without experiencing any significant installation force.

Abstract: A semiconductor filter is provided to operate in conjunction with a differential pressure transducer. The filter receives a high and very low frequency static pressure attendant with a high frequency low dynamic pressure at one end, the filter operates to filter said high frequency dynamic pressure to provide only the static pressure at the other filter end. A differential transducer receives both dynamic and static pressure at one input port and receives said filtered static pressure at the other port where said transducer provides an output solely indicative of dynamic pressure. The filter in one embodiment has a series of etched channels directed from an input end to an output end. The channels are etched pores of extremely small diameter and operate to attenuate or filter the dynamic pressure.

Abstract: There is described a temperature compensation scheme for a pressure sensitive metal diaphragm transducer. The transducer employs a Wheatstone bridge fabricated from p-type piezoresistors. The Wheatstone bridge is glassed directly onto the metal diaphragm. As the temperature of operation increases, the diaphragm exhibits a temperature variation of the Modulus of Elasticity. The Modulus of the metal diaphragm decreases with increasing temperature. Because of this, the same pressure applied to the metal diaphragm causes it to deflect further, which in turns causes increased strain applied to the bridge. Because of this effect, the sensitivity of the transducer increases with increasing temperature. A resistor is now placed in series with the Wheatstone bridge. The resistor is in series with the biasing voltage and because the TCS of the diaphragm is of an opposite sign, the series resistor has an even higher TCR in series with the bridge.

Abstract: A semiconductor filter is provided to operate in conjunction with a differential pressure transducer. The filter receives a high and very low frequency static pressure attendant with a high frequency low dynamic pressure at one end, the filter operates to filter said high frequency dynamic pressure to provide only the static pressure at the other filter end. A differential transducer receives both dynamic and static pressure at one input port and receives said filtered static pressure at the other port where said transducer provides an output solely indicative of dynamic pressure. The filter in one embodiment has a series of etched channels directed from an input end to an output end. The channels are etched pores of extremely small diameter and operate to attenuate or filter the dynamic pressure.

Abstract: A pressure sensor including: a deflectable diaphragm including a substantially central boss and channel; and, an optical waveguide having first and second arms, wherein the first arm is substantially aligned with an edge of the boss and the second arm is substantially aligned with an edge of the channel.

Abstract: A pressure sensor including: a deflectable diaphragm including a substantially central boss and channel; and, an optical waveguide having first and second arms, wherein the first arm is substantially aligned with an edge of the boss and the second arm is substantially aligned with an edge of the channel.

Abstract: A semiconductor heterostructure based pressure switch comprising: first and second small bandgap material regions separated by a larger bandgap material region; a third small bandgap material region within the region of larger bandgap material, the third material region and larger bandgap material region defining at least one quantum dot; and, first and second electrodes electrically coupled to the first and second small bandgap material regions, respectively, wherein the electrodes are sufficiently proximate to said quantum dot to facilitate electron tunneling there between when a pressure is applied to the bandgap material defining the quantum dot.

Abstract: A semiconductor heterostructure based pressure switch comprising: first and second small bandgap material regions separated by a larger bandgap material region; a third small bandgap material region within the region of larger bandgap material, the third material region and larger bandgap material region defining at least one quantum dot; and, first and second electrodes electrically coupled to the first and second small bandgap material regions, respectively, wherein the electrodes are sufficiently proximate to said quantum dot to facilitate electron tunneling there between when a pressure is applied to the bandgap material defining the quantum dot.

Abstract: A semiconductor filter is provided to operate in conjunction with a differential pressure transducer. The filter receives a high and very low frequency static pressure attendant with a high frequency low dynamic pressure at one end, the filter operates to filter said high frequency dynamic pressure to provide only the static pressure at the other filter end. A differential transducer receives both dynamic and static pressure at one input port and receives said filtered static pressure at the other port where said transducer provides an output solely indicative of dynamic pressure. The filter in one embodiment has a series of etched channels directed from an input end to an output end. The channels are etched pores of extremely small diameter and operate to attenuate or filter the dynamic pressure.

Abstract: A pressure sensor including: a deflectable diaphragm including a substantially central boss and channel; and, an optical waveguide having first and second arms, wherein the first arm is substantially aligned with an edge of the boss and the second arm is substantially aligned with an edge of the channel.

Abstract: A semiconductor filter is provided to operate in conjunction with a differential pressure transducer. The filter receives a high and very low frequency static pressure attendant with a high frequency low dynamic pressure at one end, the filter operates to filter said high frequency dynamic pressure to provide only the static pressure at the other filter end. A differential transducer receives both dynamic and static pressure at one input port and receives said filtered static pressure at the other port where said transducer provides an output solely indicative of dynamic pressure. The filter in one embodiment has a series of etched channels directed from an input end to an output end. The channels are etched pores of extremely small diameter and operate to attenuate or filter the dynamic pressure.

Abstract: There is described an accelerometer which is fabricated utilizing a beam diaphragm sensor employing dielectrically isolated resonant beams. Each resonant beam is subject to an acceleration. One beam is an acceleration sensing beam and contains a mass which is coupled to the deflecting diaphragm. As the accelerometer is subjected to acceleration, the acceleration sensing beam will alter its resonant frequency according to the applied acceleration, while the other beam is immune to acceleration and therefore, provides a relatively fixed resonant frequency. One then takes the difference frequency between the two beams to obtain an output frequency signal which is relatively independent of temperature and/or biasing changes.

Abstract: A hybrid phase locked loop employs both analog and digital circuitry. A digital to analog converter (DAC) provides a current output signal in conjunction with a current controlled oscillator (ICO). The hybrid phase locked loop employs the digital circuitry, among other reasons, to assist in generating an optimal feedback frequency signal before the loop of the hybrid phase locked loop is closed. The hybrid phase locked loop intelligently employs appropriate switching in strategically placed portions of the hybrid phase locked loop to ensure stable operation once the loop of the hybrid phase locked loop is closed. The hybrid phase locked loop employs baseline components in certain embodiments of the invention. These baseline components are those whose component values may vary significantly as a function of operating conditions, environmental perturbations, and which have relatively relaxed tolerances/precisions.

Abstract: An integrated circuit (11) has a frequency detection circuit (22) which provides one or more digital signals (50) to a current source (26) based upon a detected frequency of operation of a generated reference clock (48). The signals (50) allows the current source (26) to change its operational state between two or more discrete current output levels in a digitally-controlled manner. Using signals (50), a high current output level can selected and provided by the current source (26) to the external oscillator circuit (16) during a start up mode to ensure that the integrated circuit (11) can start up in an optimally reduced time period. After a start up operation is complete, the signals (50) can then be used to switch the current source (26) into a lower current operational mode whereby electromagnetic interference (EMI) effects are reduced during the normal modes of operation occurring after start up.