Dual frequency, dual mode quartz resonator

Claim 2

An AT-cut quartz resonator having two different sets of coupled modes simultaneously occurring that produces two resonant frequencies comprising: a generally rectangular quartz polyhedron; first and second electrodes disposed on opposing faces of said polyledron for coupling electrical energy thereto; the ratio of width to height (W/H) of said polyhedron being within the range of 8 to 25; the width (W) dimension of said polyhedron selected such that a first mode set consisting of a thickness shear mode coupled to a first flexure mode and a second mode set consisting of said thickness shear mode coupled to second flexure mode are simultaneously excitable and result in respective first and second signals of different frequencies, the first signal having a substantial magnitude relative to the magnitude of the second signal; and said polyhedron including means for causing one of the first and second signals to have a substantially cubic frequency versus temperature response over a predetermined temperature range, said means comprising said polyhedron having an AT rotation angle within the range of 34.00-34.50 degrees.

Claim 3

The resonator according to claim 1 wherein said W/H ratio is between 10 and 20.

Claim 4

The resonator according to claim 1 wherein the magnitude of the first signal is within the range of ±20% of the magnitude of the second signal.

Claim 5

The resonator according to claim 1 wherein said AT rotation angle is within the range of 34.30-34.40 degrees.

Claim 6

The resonator according to claim 1 wherein said width of the polyhedron is selected so that no substantial excitation of a face shear mode occurs.

Claim 7

The resonator according to claim 5 wherein said width of the polyhedron is selected such that the number of half-waves of flexure of the one of the first and second flexure modes coupled to said thickness shear mode that produces the lower frequency signal, when divided by 2, is an even number thereby avoiding any substantial coupling to a face shear mode.

Claim 8

The resonator according to claim 1 wherein said first and second electrodes substantially cover said opposing faces.

Claim 9

The resonator according to claim 1 wherein said means causes the frequency versus temperature characteristic of the other of the first and second signals to be substantially linear over said temperature range.

Claim 10

In an apparatus for generating an output signal wherein variations in the frequency of the signal due to temperature changes are minimized, the apparatus having a quartz resonator in which two different sets of resonant modes are simultaneously excited, means for generating first and second signals corresponding respectively to the two sets of resonant modes, means for comparing the frequencies of the first and second signals and generating an error signal representing the difference in frequency of the first and second signals, and means for compensating one of the first and second signals in response to the error signal to minimize frequency variation of the one for temperature changes, the improvement in the resonator comprising: a generally rectangular polyhedron consisting of an AT-cut quartz crystal; first and second electrodes disposed on opposing faces of said crystal for coupling said resonator to said generating means; the ratio of width to height (W/H) of said polyhedron being within the range of 8 to 25; the width (W) dimension of said polyhedron selected such that a first mode set consisting of a thickness shear mode coupled to a first flexure mode and a second mode set consisting of said thickness shear mode coupled to a second flexure mode are simultaneously excitable, said first signal having a substantial magnitude relative to said second signal; and said polyhedron including means for causing one of the first and second signals to have a substantially cubic frequency versus temperature response over a desired temperature range, said causing means comprising said polyhedron having an AT rotation angle within the range of 34.00-34.50 degrees.

Claim 11

In an apparatus for generating an output signal wherein variations in the frequency of the signal due to temperature changes are minimized, the apparatus having a quartz resonator in which two different sets of resonant modes are simultaneously excited, means for generating first and second signals corresponding respectively to the two sets of resonant modes, means for comparing the frequencies of the first and second signals and generating an error signal representing the difference in frequency of the first and second signals, and means for compensating one of the first and second signals in response to the error signal to minimize frequency variation of the one for temperature changes, the improvement in the resonator comprising: a generally rectangular polyhedron consisting of an AT-cut quartz crystal; first and second electrodes disposed on opposing faces of said crystal for coupling said resonator to said generating means; the ratio of width to height (W/H) of said polyhedron being within the range of 8 to 25; the width (W) dimension of said polyhedron selected such that a first mode set consisting of a thickness shear mode coupled to a first flexure mode and a second mode set consisting of said thickness shear mode coupled to a second flexure mode are simultaneously excitable, said first signal having a substantial magnitude relative to said second signal; and said polyhedron including means for causing one of the first and second signals to have a substantially cubic frequency versus temperature response over a desired temperature range, said causing means comprising said polyhedron having an AT rotation angle within the range of 34.00-34.50 degrees.

Claim 12

The apparatus according to claim 9 wherein said W/H ratio is between 10 and 20.

Claim 13

The apparatus according to claim 9 wherein the magnitude of the first signal is within the range of ±20% of the magnitude of the second signal.

Claim 14

The apparatus according to claim 9 wherein said AT rotation angle is within the range of 34.30-34.40 degrees.

Claim 15

The apparatus according to claim 9 wherein said width of the polyhedron is selected so that no substantial excitation of a face shear mode occurs.

Claim 16

The apparatus according to claim 13 wherein said width of the polyhedron is selected such that the number of half-waves of flexure of the one of the first and second flexure modes coupled to said thickness shear mode that produces the lower frequency signal, when divided by 2, is an even number thereby avoiding any substantial coupling to a face shear mode.

Claim 17

The apparatus according to claim 9 wherein said first and second electrodes substantially cover said opposing faces.

Claim 18

The apparatus according to claim 9 wherein said causing means causes the frequency versus temperature characteristic of the other of the first and second signals to be substantially linear over the desired temperature range.

Claim 21

The method according to claim 17 comprising the step of selecting the W/H ratio to be within the range of 10 to 20.

Claim 22

The method according to claim 17 comprising the step of selecting the width of the resonator such that the magnitude of the first signal is within 20% of the second signal.

Claim 23

The method according to claim 17 comprising the step of selecting the AT rotational angle within the range of 34.30 to 34.40 degrees.

Claim 24

An AT-cut quartz resonator having two different sets of coupled modes simultaneously occurring that produces two resonant frequencies comprising: a generally rectangular quartz polyhedron; first and second electrodes disposed on opposing faces of said polyledron for coupling electrical energy thereto; the ratio of width to height (W/H) of said polyhedron being within the range of 8 to 25; the width (W) dimension of said polyhedron selected such that a first mode set consisting of a thickness shear mode coupled to a first flexure mode and a second mode set consisting of said thickness shear mode coupled to second flexure mode are simultaneously excitable and result in respective first and second signals of different frequencies, the first signal having a substantial magnitude relative to the magnitude of the second signal; and said polyhedron having an AT rotation angle within the range of 34.00-34.50 degrees.

Claim 25

An AT-cut quartz resonator having two different sets of coupled modes simultaneously occurring that produces two resonant frequencies comprising: a generally rectangular quartz polyhedron; first and second electrodes disposed on opposing faces of said polyledron for coupling electrical energy thereto; the ratio of width to height (W/H) of said polyhedron being within the range of 8 to 25; the width (W) dimension of said polyhedron selected such that a first mode set consisting of a thickness shear mode coupled to a first flexure mode and a second mode set consisting of said thickness shear mode coupled to second flexure mode are simultaneously excitable and result in respective first and second signals of different frequencies, the first signal having a substantial magnitude relative to the magnitude of the second signal; and said polyhedron having an AT rotation angle within the range of 34.00-34.50 degrees.

Claim 26

The resonator according to claim 21 wherein said W/H ratio is between 10 and 20.

Claim 27

The resonator according to claim 21 wherein the magnitude of the first signal is within the range of ±20% of the magnitude of the second signal.

Claim 28

The resonator according to claim 21 wherein said AT rotation angle is within the range of 34.30-34.40 degrees.

Claim 29

The resonator according to claim 21 wherein said width of the polyhedron is selected so that no substantial excitation of a face shear mode occurs.

Claim 30

The resonator according to claim 25 wherein said width of the polyhedron is selected such that the number of half-waves of flexure of the one of the first and second flexure modes coupled to said thickness shear mode that produces the lower frequency signal, when divided by 2, is an even number thereby avoiding any substantial coupling to a face shear mode.

Claim 31

The resonator according to claim 21 wherein said first and second electrodes substantially cover said opposing faces.