Abstract: In a process of producing crystal resonators in which the direction and magnitude of the gamma vector is substantially the same for each resonator, a method of altering the resonator during the process to change the resonator mass, shape, or electrode placement so as to reduce the gamma vector magnitude of each crystal. This alteration may be done by adding mass, removing mass, or both adding and removing mass, or by positioning the electrodes to selectively position the electric field in the crystal, all in order to move the location of the active region of vibration and thereby reduce the gamma vector.

Abstract: Structure for mounting a disc-shaped crystal, having a top and bottom surface, of a crystal resonator includes four attachment pads affixed to the crystal on the bottom surface near the perimeter thereof, four base pads affixed to a base surface, and four generally elongate parallel support elements, each extending from a different one of the base pads to a different one of the attachment pads to support the crystal. The support elements are generally longitudinally rigid and laterally elastic so that lateral movement of the crystal may take place without torque being applied to either the pads or the crystal. In other words, when the crystal is moved sideways, the plane of the crystal remains generally parallel with the previous plane occupied by the crystal.

Abstract: In a process of producing crystal resonators in which the direction and magnitude of the gamma vector is substantially the same for each resonator, a method of altering the resonator during the process to change the resonator mass, shape, or electrode placement so as to reduce the gamma vector magnitude of each crystal. This alteration may be done by adding mass, removing mass, or both adding and removing mass, or by positioning the electrodes to selectively position the electric field in the crystal, all in order to move the location of the active region of vibration and thereby reduce the gamma vector.

Abstract: In a process of producing crystal resonators in which the direction and magnitude of the gamma vector is substantially the same for each resonator, a method of altering the resonator during the process to change the resonator mass, shape, or electrode placement so as to reduce the gamma vector magnitude of each crystal. This alteration may be done by adding mass, removing mass, or both adding and removing mass, or by positioning the electrodes to selectively position the electric field in the crystal, all in order to move the location of the active region of vibration and thereby reduce the gamma vector.

Abstract: Crystal resonator with low acceleration sensitivity includes a piezoelectric quartz crystal, support structure for holding the crystal and a signal source for causing the crystal to resonate with an active region of vibration. The resonator is modified, if need be, to control (generally reduce) the gamma vector which is a measure of the acceleration senstivity. This may be done by adding mass, removing mass, or both adding and removing mass, all in order to move or change the shape of the active region of vibration and thereby reduce the gamma vector.

Abstract: A quartz resonator pressure transducer includes a generally disc-shaped resonator section adapted to vibrate in response to an oscillatory signal, a housing having sidewalls which generally circumscribe the resonator section and extend in opposite directions generally normal to the plane of the resonator section, and a web, thinner than the resonator section, joining the housing to the perimeter of the resonator section to define grooves between the sidewalls of the housing and the resonator section on the top and bottom sides of the section.

Abstract: An AT-cut quartz resonator pressure transducer includes a generally disc-shaped resonator section, a housing surrounding the resonator section and joined to the perimeter thereof, with the walls of the housing extending in opposite directions generally normal to the plane of the resonator section. Selected portions of the sidewalls are made thinner than the remaining sidewall portions so that when the housing is immersed in a fluid, a non-uniform stress will be produced in the resonator section. The housing and resonator section are formed so that the frequency of vibration of the resonator section is substantially independent of temperature and relatively independent of temperature transients.

Abstract: Fluid density measuring apparatus and method for directly measuring fluid density or indirectly measuring force, acceleration, flow velocity, differential pressure and other parameters affecting the apparatus. The apparatus includes a bellows and a generally rigid hollow housing having openings through which fluid may flow to the interior of the housing, and a vibratory single-ended tuning fork mounted in the housing. The apparatus also includes circuitry for causing the tines of the tuning fork to resonate, for example, 180 degrees out of phase in a transverse direction, with the frequency of the tines varying with variation in the density of the fluid surrounding the tines. Circuitry is also included for determining the frequency at which the tuning fork tines resonate. When the density of the fluid into which the housing is placed changes, the frequency of vibration of the tines of the tuning fork is caused to change to provide a measure of the density change.

Abstract: Fluid density measuring apparatus and method for directly measuring fluid density or indirectly measuring pressure. The apparatus includes a bellows and a generally rigid hollow housing having openings through which fluid may flow to the interior of the housing, and a vibratory single-ended tuning fork mounted in the housing. The apparatus also includes circuitry for causing the tines of the tuning fork to resonate, for example, 180 degrees out of phase in a transverse direction, with the frequency of the tines varying with variation in the density of the fluid surrounding the tines. Circuitry is also included for determining the frequency at which the tuning fork tines resonate. When the density of the fluid into which the housing is placed changes, the frequency of vibration of the tines of the tuning fork is caused to change to provide a measure of the pressure.

Abstract: Fluid density measuring apparatus and method for directly measuring fluid density or indirectly measuring pressure, temperature, acceleration, flow velocity, differential pressure and other parameters affecting the apparatus. The apparatus includes a generally rigid hollow housing having openings through which fluid may flow to the interior of the housing, and a vibratory single-ended tuning fork mounted in the housing. The apparatus also includes circuitry for causing the tines of the tuning fork to resonate, for example, 180 degrees out of phase in a transverse direction, with the frequency of the tines varying with variation in the density of the fluid surrounding the tines. Circuitry is also included for determining the frequency at which the tuning fork tines resonate. When the density of the fluid into which the housing is placed changes, the frequency of vibration of the tines of the tuning fork is caused to change to provide a measure of the density change.

Abstract: A quartz resonator pressure transducer includes a generally disc-shaped resonator section, a housing surrounding the resonator section and joined to the perimeter thereof, with the walls of the housing extending in opposite directions generally normal to the plane of the resonator section. Selected portions of the sidewalls are made thinner than the remaining sidewall portions so that when the housing is immersed in a fluid, a non-uniform stress will be produced in the resonator section. The housing and resonator section are formed so that the frequency of vibration of the resonator section is substantially independent of temperature and relatively independent of temperature transients.

Abstract: A method and apparatus for measuring force or other parameters and temperature. The apparatus includes an oscillator and a vibratory element, such as a quartz crystal, which is caused to resonate by the oscillator at two frequencies f.sub.1 and f.sub.2 selected from the fundamental frequency and its overtone frequencies of the vibratory element. The vibratory element is selected so that the two frequencies f.sub.1 and f.sub.2 both vary with variation in force (or other parameter) applied to the element and with variation in temperature of the element, and so that the magnitude or scale factor of variation for frequency f.sub.1 is different from that for frequency f.sub.2. The apparatus also includes a detection device for detecting the frequencies f.sub.1 and f.sub.

Abstract: Fluid density measuring apparatus and method for directly measuring fluid density or indirectly measuring pressure, temperature, acceleration, flow velocity, differential pressure and other parameters affecting the apparatus. The apparatus includes a generally rigid hollow housing having openings through which fluid may flow to the interior of the housing, and a vibratory single-ended tuning fork mounted in the housing. The apparatus also includes circuitry for causing the tines of the tuning fork to resonate, for example, 180 degrees out of phase in a transverse direction, with the frequency of the tines varying with variation in the density of the fluid surrounding the tines. Circuitry is also included for determining the frequency at which the tuning fork tines resonate. When the density of the fluid into which the housing is placed changes, the frequency of vibration of the tines of the tuning fork is caused to change to provide a measure of the density change.