Phase controlled oscillator circuit with input signal coupler
View Patent ↗An oscillating signal in an oscillator is caused to phase shift toward the phase of an input signal coupled to the oscillating signal. The resonant frequency of the oscillator is about equal to an integer multiple of the frequency of the input signal. The input signal may be generated in a pulse generator to have an input pulse duration less than or equal to that of the oscillating signal. The oscillator circuit may be used as a filter to filter pulse width variations or to filter jitter from a reference clock. The oscillator circuit may also serve as a buffer by amplifying the input signal. Phase interpolation can be obtained by coupling at least one input signal with at least one oscillating signal.
1. An oscillator circuit comprising:
an oscillator having a resonant frequency;
an input signal having a frequency about equal to or less than the resonant frequency and having a phase, where the input signal comprises a reference clock and a delayed version of the reference clock;
the resonant frequency being about equal to an integer multiple of the frequency of the input signal;
a coupler which couples the input signal to an oscillating signal in the oscillator to cause a phase shift of the oscillating signal toward the phase of the input signal;
the input signal having a pulse duration less than or equal to a pulse duration of the oscillating signal; and
the oscillator circuit filtering jitter from the input signal.
2. An oscillator circuit as claimed in claim 1 wherein the coupler comprises a partial NAND gate.
3. An oscillator circuit as claimed in claim 1 wherein the coupler comprises a partial NOR gate.
4. An oscillator circuit as claimed in claim 1 wherein the coupler comprises a conductance between phases of the oscillator.
5. An oscillator circuit as claimed in claim 1 wherein the conductance comprises a transmission gate.
6. An oscillator circuit as claimed in claim 1 wherein the oscillator is an LC oscillator.
7. An oscillator circuit as claimed in claim 1 wherein the coupler comprises an inverter.
8. An oscillator circuit as claimed in claim 1 wherein the coupler comprises a resistor.
9. An oscillator circuit comprising:
an oscillator having a resonant frequency;
an input signal having a frequency about equal to or less than the resonant frequency and having a phase;
the resonant frequency being about equal to an integer multiple of the frequency of the input signal;
a coupler which couples the input signal to an oscillating signal in the oscillator to cause a phase shift of the oscillating signal toward the phase of the input signal;
the input signal having a pulse duration less than or equal to a pulse duration of the oscillating signal; and
the oscillator circuit filtering jitter from the input signal, wherein an active edge of the input signal moves the phase of the oscillating signal a portion of the distance needed to align the oscillating signal with the input signal.
10. An oscillator circuit as claimed in claim 9 wherein the coupler comprises a partial NAND gate.
11. An oscillator circuit as claimed in claim 9 wherein the coupler comprises a partial NOR gate.
12. An oscillator circuit as claimed in claim 9 wherein the coupler comprises a conductance between phases of the oscillator.
13. An oscillator circuit as claimed in claim 9 wherein the conductance comprises a transmission gate.
14. An oscillator circuit as claimed in claim 9 wherein the oscillator is an LC oscillator.
15. An oscillator circuit as claimed in claim 9 wherein the coupler comprises an inverter.
16. An oscillator circuit as claimed in claim 9 wherein the coupler comprises a resistor.
17. An oscillator circuit comprising:
an oscillator having a resonant frequency;
an input signal having a frequency about equal to the resonant frequency and having a phase;
a coupler which couples the input signal to an oscillating signal in the oscillator to cause a phase shift of the oscillating signal toward the phase of the input signal; and
the oscillator circuit, in combination with an input oscillator which generates the input signal from a reference clock, the oscillator circuit filtering jitter from the reference clock; and
the oscillator circuit filtering jitter from the input signal.
18. An oscillator circuit as claimed in claim 17 wherein the coupler comprises a partial NAND gate.
19. An oscillator circuit as claimed in claim 17 wherein the coupler comprises a partial NOR gate.
20. An oscillator circuit as claimed in claim 17 wherein the coupler comprises a conductance between phases of the oscillator.
21. An oscillator circuit as claimed in claim 17 wherein the conductance comprises a transmission gate.
22. An oscillator circuit as claimed in claim 17 wherein the oscillator is an LC oscillator.
23. An oscillator circuit as claimed in claim 17 wherein the coupler comprises an inverter.
24. An oscillator circuit as claimed in claim 17 wherein the coupler comprises a resistor.
25. An oscillator circuit comprising:
an oscillator having a resonant frequency;
an input signal having a frequency about equal to the resonant frequency and having a phase;
a coupler which couples the input signal to an oscillating signal in the oscillator to cause a phase shift of the oscillating signal toward the phase of the input signal;
the coupler providing a filtering time constant which is greater than a cycle time of the input signal; and
the oscillator circuit filtering jitter from the input signal.
26. An oscillator circuit as claimed in claim 25 wherein the coupler comprises a partial NAND gate.
27. An oscillator circuit as claimed in claim 25 wherein the coupler comprises a partial NOR gate.
28. An oscillator circuit as claimed in claim 25 wherein the coupler comprises a conductance between phases of the oscillator.
29. An oscillator circuit as claimed in claim 25 wherein the conductance comprises a transmission gate.
30. An oscillator circuit as claimed in claim 25 wherein the oscillator is an LC oscillator.
31. An oscillator circuit as claimed in claim 25 wherein the coupler comprises an inverter.
32. An oscillator circuit as claimed in claim 25 wherein the coupler comprises a resistor.
33. An oscillator circuit comprising:
an oscillator having a resonant frequency;
an input signal having a frequency about equal to or less than the resonant frequency and having a phase;
a coupler which couples the input signal to an oscillating signal in the oscillator to cause a phase shift of the oscillating signal toward the phase of the input signal, wherein the coupler comprises a partial NAND gate; and
the oscillator circuit filtering jitter from the input signal.
34. An oscillator circuit comprising:
an oscillator having a resonant frequency;
an input signal having a frequency about equal to or less than the resonant frequency and having a phase;
a coupler which couples the input signal to an oscillating signal in the oscillator to cause a phase shift of the oscillating signal toward the phase of the input signal, wherein the coupler comprises a partial NOR gate; and
the oscillator circuit filtering jitter from the input signal.
35. An oscillator circuit comprising:
an oscillator having a resonant frequency;
an input signal having a frequency about equal to or less than the resonant frequency and having a phase;
a coupler which couples the input signal to an oscillating signal in the oscillator to cause a phase shift of the oscillating signal toward the phase of the input signal;
the coupler having a conductance between phases of the oscillator, wherein the conductance comprises an FET; and
the oscillator circuit filtering jitter from the input signal.
36. An oscillator circuit comprising:
an oscillator having a resonant frequency;
an input signal having a frequency about equal to or less than the resonant frequency and having a phase;
a coupler which couples the input signal to an oscillating signal in the oscillator to cause a phase shift of the oscillating signal toward the phase of the input signal;
the coupler having a conductance between phases of the oscillator wherein the conductance comprises a transmission gate; and
the oscillator circuit filtering jitter from the input signal.
37. An oscillator circuit comprising:
an oscillator having a resonant frequency;
an input to receive an input signal having a frequency about equal to or less than the resonant frequency and having a phase; and
the oscillator circuit filtering jitter from the input signal, where an active edge of the input signal moves phase of the oscillating signal a portion of the distance needed to align the oscillating signal with the input signal.
38. An oscillator circuit as claimed in claim 37 in combination with an input oscillator which generates the input signal from a reference clock, the oscillator circuit filtering jitter from the reference clock.
39. An oscillator circuit as claimed in claim 37 further includes a coupler which couples the input signal to an oscillating signal in the oscillator to cause a phase shift of the oscillating signal toward the phase of the input signal.
40. An oscillator circuit as claimed in claim 39 wherein the coupler provides a filtering time constant which is greater than a cycle time of the input signal.
41. An oscillator circuit as claimed in claim 39 wherein the oscillator filters pulse width variations of the input signal.
42. An oscillator circuit comprising:
oscillator means having a resonant frequency;
an input signal having a frequency about equal to or less than the resonant frequency and having a phase; and
the oscillator circuit having filtering means for filtering jitter from the input signal, where an active edge of the input signal moves the phase of the oscillating signal a portion of the distance needed to align it with the input signal.