Low allan-deviation oscillator
An oscillator includes a resonator, sustaining circuit and detector circuit. The sustaining circuit receives a sense signal indicative of mechanically resonant motion of the resonator generates an amplified output signal in response. The detector circuit asserts, at a predetermined phase of the amplified output signal, one or more control signals that enable an offset-reducing operation with respect to the sustaining amplifier circuit.
1. A device comprising:
a die;
a body on the die; and
circuitry comprising a sustaining amplifier to provide a drive signal to excite the body to vibrate at a frequency during operation of the device;
wherein the circuitry is further to assert, one or more control signals that provide for offset-cancellation for the sustaining amplifier at a rate equal to the frequency; and
wherein the sustaining amplifier is a bipolar junction circuit structure.
2. The device of claim 1 wherein the device is a microelectromechanical systems (MEMS) device.
3. The device of claim 2 wherein the MEMS device comprises a MEMS resonator.
4. The device of claim 3 wherein said resonator is a piezoelectric resonator.
5. The device of claim 3 wherein said resonator is an electrostatic resonator and wherein the body is to be coupled to a bias voltage, and where the offset cancelation is to cause the drive signal to swing symmetrically about the bias voltage.
6. The device of claim 1 wherein the device comprises a resonator, wherein the frequency is a resonant frequency (f) of oscillation, and wherein the device is structured to generate an oscillation signal that is characterized by a 1/f noise corner that is at a lower frequency than the Leeson integration corner of the resonator.
7. The device of claim 6 wherein the 1/f noise corner is below ten hertz.
8. The device of claim 6 wherein the resonator is a quartz crystal resonator.
9. The device of claim 6 wherein the resonator is a LC resonator.
10. The device of claim 1 wherein the circuitry also comprises an electrode to sense motion of the body and to provide an electrical output and a zero crossing detector to detect zero crossings based on the electrical output, and wherein the circuitry is to generate the one or more control signals that provide the offset-cancellation for the sustaining amplifier as a function of zero crossings detected by the zero crossing detector.
11. The device of claim 1 wherein the device comprises a resonator, wherein the frequency is a resonant frequency (f) of oscillation, and wherein the circuitry comprises a fractional-N phase locked loop to generate a frequency-multiplied clock signal at a frequency of f*N.
12. The device of claim 11 , embodied as a packaged integrated circuit device, further comprising a pin to output the frequency-multiplied clock signal.
13. A device comprising:
a die;
a body on the die; and
circuitry comprising a sustaining amplifier to provide a drive signal to excite the body to vibrate at a frequency during operation of the device;
wherein the circuitry is further to assert, one or more control signals that provide for offset-cancellation for the sustaining amplifier at a rate equal to the frequency; and
wherein the sustaining amplifier is a complementary metal oxide semiconductor (CMOS) structure.
14. The device of claim 1 wherein the circuitry is to assert the one or more control signals at a predetermined phase relative to the frequency.
15. A device comprising:
a die;
a microelectromechanical systems (MEMS) resonator having a body on the die; and
circuitry comprising a sustaining amplifier to provide a drive signal to excite the body to vibrate at a frequency (f) during operation of the device;
wherein the circuitry is further to assert, one or more control signals that provide for offset-cancellation for the sustaining amplifier at a rate equal to the frequency; and
wherein the sustaining amplifier comprises bipolar junction devices and is characterized by a 1/f noise corner that is at a lower frequency than the Leeson integration frequency of the MEMS resonator.
16. The device of claim 15 wherein the circuitry comprises a fractional-N phase locked loop to generate a frequency-multiplied clock signal at a frequency of f*N.
17. The device of claim 16 , embodied as a packaged integrated circuit device, further comprising a pin to output the frequency-multiplied clock signal.
18. The device of claim 15 wherein the circuitry is to assert the one or more control signals at a predetermined phase relative to the frequency.
19. An oscillator integrated circuit comprising:
a die;
a microelectromechanical systems (MEMS) resonator having a body on the die; and
circuitry comprising a sustaining amplifier to provide a drive signal to excite the body to vibrate at a frequency (f) during operation of the device;
wherein the circuitry is further to assert, one or more control signals that provide for offset-cancellation for the sustaining amplifier at a rate equal to the frequency;
wherein the sustaining amplifier comprises bipolar junction devices and is characterized by a 1/f noise corner that is at a lower frequency than the Leeson integration frequency of the MEMS resonator;
wherein the circuitry further comprises a fractional-N phase locked loop to generate a frequency-multiplied clock signal at a frequency of f*N; and
wherein the oscillator integrated circuit further comprises a pin to output the frequency-multiplied clock signal.
20. A device comprising:
a die;
a body on the die; and
circuitry comprising a sustaining amplifier to provide a drive signal to excite the body to vibrate at a frequency during operation of the device;
wherein the circuitry is further to assert, one or more control signals that provide for offset-cancellation for the sustaining amplifier at a rate equal to the frequency;
wherein the MEMS device comprises a MEMS resonator; and
wherein said MEMS resonator is a piezoelectric resonator.