Quality of phase lock and loss of lock detector

1. A method comprising:

detecting an output frequency;

comparing the output frequency with a first reference signal;

providing a first signal and a second signal as a function of the output frequency and first reference signal comparison;

receiving a predetermined threshold from a second reference signal;

monitoring a deviation of the first and second signals from the predetermined threshold;

generating a third signal as a function of the deviation;

comparing the third signal to a window threshold wherein the window threshold is set based on a predetermined loop variable;

generating a fourth signal a function of the third signal and the window threshold comparison; and

providing an alarm based on the fourth signal.

2. The method of claim 1 , wherein the fourth signal represents at least a predetermined amount of static error.

3. The method of claim 1 , wherein the first signal is a function of static phase detector gain.

4. The method of claim 1 , wherein the third signal and window threshold comparison further comprises measured static error from the window threshold.

5. The method of claim 1 , wherein the predetermined loop variable includes oscillator gain, loop compensation, charge pump gain variation, or any combination thereof.

6. The method of claim 1 , wherein the alarm is a loss of frequency lock alarm.

7. A phase locked loop circuit, comprising:

means for providing an output frequency;

means for detecting the output frequency of the means for providing the output frequency;

means for comparing the output frequency with a first reference signal;

means for outputting a first signal and a second signal as a function of the output frequency and first reference signal comparison;

means for receiving the first and second signals;

means for receiving a predetermined threshold from a second reference signal;

means for monitoring a deviation of the first and second signals from the predetermined threshold;

means for generating a third signal as a function of the deviation;

means for receiving the third signal;

means for comparing the third signal to a window threshold;

means for generating a fourth signal as a function of the third signal and window threshold comparison, wherein the window threshold is set based on a predetermined loop variable; and

an alarm circuit which receives the fourth signal and is adaptable to provide an alarm.

8. The system of claim 7 , wherein the fourth signal represents at least a predetermined amount of static error.

9. The system of claim 7 , wherein the first signal is a function of static phase detector gain.

10. The system of claim 7 , wherein the third signal and window threshold comparison further comprises measured static error from the window threshold.

11. The system of claim 7 , wherein the predetermined loop variable includes oscillator gain, loop compensation, charge pump gain variation, or any combination thereof.

12. The system of claim 7 , wherein the alarm is a loss of frequency lock alarm.

13. A method comprising:

detecting an output frequency of an oscillator;

comparing the output frequency with a first reference signal;

generating a first signal and a second signal as a function of the output frequency and first reference signal comparison;

receiving a predetermined threshold from a second reference signal;

monitoring a deviation of the first and second signals from the predetermined threshold;

generating a third signal as a function of the deviation;

comparing the third signal to a window threshold, wherein the window threshold is set based on a predetermined loop variable of the phase locked loop and provides upper and lower levels for an oscillator parameter;

generating a fourth signal as a function of the third signal and window threshold comparison; and

providing an alarm.

14. The method of claim 13 , wherein the fourth signal represents at least a predetermined amount of static error.

15. The method of claim 13 , wherein the first signal is a function of static phase detector gain.

16. The method of claim 13 , wherein the third signal and window threshold comparison further comprises measured static error from the window threshold.

17. The method of claim 13 , wherein the predetermined loop variable includes oscillator gain, loop compensation, charge pump gain variation, or any combination thereof.

18. The method of claim 13 , wherein the alarm is a loss of frequency lock alarm.

19. A system comprising:

means for detecting the output frequency of an oscillator;

means for comparing the output frequency with a first reference signal;

means for outputting a first signal and a second signal as a function of the output frequency and first reference signal comparison;

means for receiving the first and second signals;

means for receiving a predetermined threshold from a second reference signal at an input of the amplifying circuit;

means for monitoring a deviation of the first and second signals from the predetermined threshold;

means for generating a third signal as a function of the deviation;

means for receiving the third signal;

means for comparing the third signal to a window threshold;

means for generating a fourth signal as a function of the third signal and window threshold comparison, wherein the window threshold is set based on a predetermined loop variable of the phase locked loop and provides upper and lower levels for an oscillator parameter; and

means for receiving the fourth signal and for providing an alarm.

20. The method of claim 19 , wherein the first signal is a function of static phase detector gain.