Gain control methods and systems in an amplifier assembly
View Patent ↗A Variable Gain Amplifier (VGA) amplifies an input signal according to a gain, to produce an amplified signal. A detector module detects a power indicative of a power of the amplified signal. A comparator module compares the detected power to a high threshold, a low threshold and a target threshold intermediate the high and low thresholds. A controller module changes the gain of the VGA so as to drive the detected power in a direction toward the middle threshold when the comparator module indicates the detected power is not between the high and low thresholds.
1. A method for controlling a gain in an amplifier assembly, the amplifier assembly including a first gain stage and a second gain stage, comprising:
(a) determining whether a power level of an output of the amplifier assembly is within an automatic gain control (AGC) window at periodically spaced time intervals; and
(b) changing the gain of the amplifier assembly so as to drive the power level of the output of the amplifier assembly in a direction toward a target threshold, the target threshold being within the AGC window, if the power level of the output of the amplifier assembly is not within the AGC window.
2. The method of claim 1 , wherein step (b) comprises:
(b)(i) generating one or more gain change control signals to indicate a direction of gain change of the gain of the amplifier assembly.
3. The method of claim 2 , wherein step (b) further comprises:
(b)(ii) selecting at least one first gain stage in the amplifier assembly to be deactivated based upon the one or more gain change control signals; and
(b)(iii) selecting at least one second gain stage in the amplifier assembly to be activated based upon the one or more gain control signals to drive the power level of the output of the amplifier assembly in the direction toward the target threshold.
4. The method of claim 1 , wherein step (b) comprises:
(b)(i) generating at least one ramp signal according to a ramp function to change the gain of the amplifier assembly; and
(b)(ii) changing the gain of the amplifier assembly based upon the at least one ramp signal so as to drive the power level of the output of the amplifier assembly in the direction toward the target threshold.
5. A method for controlling a gain in an amplifier assembly, the amplifier assembly including a first gain stage and a second gain stage, comprising:
(a) determining whether a power level of an output of the amplifier assembly is within an automatic gain control (AGC) window; and
(b) if the power level of the output of the amplifier assembly is not within the AGC window, changing the gain of the amplifier assembly by:
(i) generating at least one ramp signal according to a ramp function to change the gain of the amplifier assembly,
(ii) monitoring a ramp state signal to determine when the at least one ramp signal has settled to a final fixed value, and
(iii) changing the gain of the amplifier assembly based upon the at least one ramp signal after the at least one ramp signal has settled to the final fixed value so as to drive the power level of the output of the amplifier assembly in the direction toward the target threshold.
6. A method for controlling a gain in an amplifier assembly, the amplifier assembly including a first gain stage and a second gain stage, comprising:
(a) setting the gain of the amplifier assembly to an initial value;
(b) amplifying an input signal using the amplifier assembly to produce an amplified signal, the gain of the amplifier assembly being set to the initial value;
(c) determining whether a power level of the amplified signal is within an automatic gain control (AGC) window at periodically spaced time intervals; and
(d) changing the gain of the amplifier assembly so as to drive the power level of the output of the amplifier assembly in a direction toward a target threshold, the target threshold being within the AGC window, if the power level of the amplified signal is not within the AGC window.
7. The method of claim 6 , wherein step (a) comprises:
(a)(i) setting a gain of the first gain stage to a maximum gain; and
(a)(ii) setting a gain of the second gain stage to a minimum gain to set the gain of the amplifier assembly to the initial value.
8. The method of claim 7 , wherein step (a)(i) comprises:
(a)(i)(A) setting a first switch in a switch matrix corresponding to the first gain stage to a first switch configuration to set the gain of the first gain stage to the maximum gain.
9. The method of claim 7 , wherein step (a)(ii) comprises:
(a)(ii)(A) setting a second switch in a switch matrix corresponding to the second gain stage to a second switch configuration to set the gain of the second gain stage to the minimum gain.
10. The method of claim 6 , wherein step (d) comprises:
(d)(i) generating one or more gain change control signals to indicate a direction of gain change of the gain of the amplifier assembly.
11. The method of claim 10 , wherein step (d) further comprises:
(d)(ii) selecting at least one first gain stage in the amplifier assembly to be deactivated based upon the one or more gain change control signals; and
(d)(iii) selecting at least one second gain stage in the amplifier assembly to be activated based upon the one or more gain control signals to drive the power level of the output of the amplifier assembly in the direction toward the target threshold.
12. The method of claim 10 , wherein step (d) further comprises:
(d)(ii) indicating to a switch matrix one or more gain stages among the first gain stage to be deactivated and one or more gain stages among the second gain stage to be activated so as to drive the power level of the output of the amplifier assembly in the direction toward the target threshold.
13. The method of claim 6 , wherein step (d) comprises:
(d)(i) generating at least one ramp signal according to at least one ramp function to change the gain of the amplifier assembly; and
(d)(ii) changing the gain of the amplifier assembly based upon the at least one ramp signal so as to drive the power level of the output of the amplifier assembly in the direction toward the target threshold.
14. A method for controlling a gain in an amplifier assembly, comprising:
(a) selecting at least one gain stage in the amplifier assembly to be activated or deactivated, and
(b) activating or deactivating the at least one gain stage in response to at least one ramp signal so as to drive a power level of an output of the amplifier assembly in a direction toward a target threshold;
(c) determining whether the power level of the output of the amplifier assembly substantially exceeds the target threshold; and
(d) repeating steps (a) through (c) at periodically spaced time intervals if the power level of the output of the amplifier assembly does not substantially exceed the target threshold.
15. The method of claim 14 , further comprising:
(e) generating one or more gain change control signals to indicate a direction of gain change if the power level of the output of the amplifier assembly does not substantially exceed the target threshold, and wherein step (d) comprises:
(d)(i) repeating steps (a), (b), (c), and (e) at periodically spaced time intervals if the power level of the output of the amplifier assembly does not substantially exceed the target threshold.
16. The method of claim 15 , wherein step (a) comprises:
(a)(i) selecting the at least one gain stage of the amplified assembly to be activated or deactivated based upon the one or more gain change control signals.
17. The method of claim 3 , wherein the at least one first gain stage is selected from the first gain stage and the at least one second gain stage is selected from the second gain stage such that the power level of the output of the amplifier assembly is decreased.
18. The method of claim 3 , wherein the at least one first gain stage is selected from the second gain stage and the at least one second gain stage is selected from the first gain stage such that the power level of the output of the amplifier assembly is decreased.
19. The method of claim 11 , wherein the at least one first gain stage is selected from the first gain stage and the at least one second gain stage is selected from the second gain stage such that the power level of the output of the amplifier assembly is decreased.
20. The method of claim 11 , wherein the at least one first gain stage is selected from the second gain stage and the at least one second gain stage is selected from the first gain stage such that the power level of the output of the amplifier assembly is decreased.
21. The method of claim 14 , further comprising:
(e) monitoring a ramp state signal to determine when the at least one ramp signal has settled to a final fixed value.
22. The method of claim 15 , wherein step (a) comprises:
(a)(i) selecting at least one first gain stage in the amplifier assembly to be deactivated based upon the one or more gain change control signals; and
(a)(ii) selecting at least one second gain stage in the amplifier assembly to be activated based upon the one or more gain control signals to drive the power level of the output of the amplifier assembly in the direction toward the target threshold.
23. The method of claim 22 , wherein the at least one first gain stage is selected from the first gain stage and the at least one second gain stage is selected from the second gain stage such that the power level of the output of the amplifier assembly is decreased.
24. The method of claim 22 , wherein the at least one first gain stage is selected from the second gain stage and the at least one second gain stage is selected from the first gain stage such that the power level of the output of the amplifier assembly is decreased.