Coupled timing oscillators
Coupled timing oscillators are described. The coupling may be electrical, mechanical, or electromechanical in some instances. In some cases, the timing oscillators include mechanical resonators. Any number of timing oscillators may be coupled. The coupled timing oscillators may be operated cooperatively to produce an oscillating signal with improved signal characteristics, such as phase noise and jitter.
1. A device, comprising:
a first timing oscillator configured to receive a first drive signal and output from a first microelectromechanical system (MEMS) resonator a first oscillating signal;
a second timing oscillator configured to receive a second drive signal and output from a second MEMS resonator a second oscillating signal,
wherein an output terminal of the first timing oscillator is coupled to an input terminal of the second timing oscillator and wherein an output terminal of the second timing oscillator is coupled to an input terminal of the first timing oscillator.
2. The device of claim 1 , wherein the first MEMS resonator comprises an active layer and a multi-layer temperature compensation structure.
3. The device of claim 2 , wherein the temperature compensation structure comprises a first layer formed of a first material having a stiffness which increases with increasing temperature over a first operating temperature range and a second layer formed of a second material having a stiffness which decreases with increasing temperature over the first operating temperature range.
4. The device of claim 1 , wherein the first and second timing oscillators are configured to self-synchronize.
5. The device of claim 1 , wherein the first timing oscillator comprises a piezoelectric mechanical resonator configured to produce the first oscillating signal.
6. The device of claim 1 , wherein the first and second output signals have different frequencies from each other, and wherein the first output signal is characterized by lower phase noise than the second output signal.
7. A device, comprising:
a first timing oscillator configured to receive a first drive signal and output a first oscillating signal, the first timing oscillator including a first mechanical resonator;
a second timing oscillator configured to receive a second drive signal and output a second oscillating signal, the second timing oscillator including a second mechanical resonator,
wherein the first and second mechanical resonators are coupled to each other.
8. The device of claim 7 , wherein the first mechanical resonator is a suspended, piezoelectric Lamb wave resonator configured to exhibit in-plane vibration in response to being excited by the first drive signal.
9. The device of claim 7 , wherein the first and second mechanical resonators are mechanically coupled to each other.
10. The device of claim 7 , wherein the first and second mechanical resonators are electrically coupled to each other.
11. The device of claim 7 , wherein the first and second mechanical resonators are capacitively coupled to each other.
12. A method, comprising:
producing an oscillating reference signal from two or more coupled timing oscillators, wherein producing the oscillating reference signal comprises electromechanically coupling a mechanical resonator of a first timing oscillator of the two or more timing oscillators with a mechanical resonator of a second timing oscillator of the two or more timing oscillators.
13. The method of claim 12 , wherein producing the oscillating reference signal comprises providing an output signal from the first timing oscillator of the two or more coupled timing oscillators to an input terminal of the second timing oscillator of the two or more coupled timing oscillators, and further providing an output signal from the second timing oscillator to an input terminal of the first timing oscillator.
14. The method of claim 12 , further comprising producing a plurality of oscillating reference signals from the two or more coupled timing oscillators including the oscillating reference signal, wherein a first oscillating reference signal of the plurality of oscillating reference signals has a first frequency and wherein a second oscillating reference signal of the plurality of oscillating reference signals has a second frequency different than the first frequency.
15. The method of claim 14 , wherein the first oscillating reference signal is characterized by lower phase noise than the second oscillating reference signal.
16. The method of claim 14 , wherein the first oscillating reference signal is characterized by lower jitter than the second oscillating reference signal.
17. The method of claim 12 , further comprising synchronizing operation of the two or more coupled timing oscillators, and wherein producing the oscillating reference signal from the two or more coupled timing oscillators is performed after synchronizing the operation of the two or more coupled timing oscillators.