Measuring a signal using a programmable gain amplifier

1. A method for measuring a signal, comprising:

setting a gain numerator of a gain value using a gain numerator signal;

setting a gain denominator of the gain value using a gain denominator signal, the gain value comprising a ratio of the gain numerator to the gain denominator;

receiving an input signal;

adjusting the input signal in accordance to the gain value to yield an output signal;

determining whether the output signal is within or outside of a threshold range;

measuring the input signal according to the output signal and a reciprocal of the gain value, the reciprocal comprising a ratio of the gain denominator to the gain numerator; and

adjusting the gain value in accordance with the determination of whether the output signal is within or outside of the threshold range by performing at least one of he following:

adjusting the gain numerator signal; and

adjusting the gain denominator signal.

2. The method of claim 1 , wherein measuring the input signal according to the output signal and the reciprocal of the gain value comprises:

determining that the output signal is outside of the threshold range; and

reporting that the output signal is outside of the threshold range.

3. The method of claim 1 , wherein measuring the input signal according to the output signal and the reciprocal of the gain value comprises:

determining that the output signal is within the threshold range; and

calculating the input signal by multiplying the reciprocal of the gain value and the output signal.

4. The method of claim 1 , wherein:

setting the gain numerator of the gain value comprises setting a first resistance of a gain amplifier; and

setting the gain denominator of the gain value comprises setting a second resistance of the gain amplifier.

5. The method of claim 1 , wherein:

setting the gain denominator of the gain value comprises setting a first capacitance of a gain amplifier; and

setting the gain numerator of the gain value comprises setting a second capacitance of the gain amplifier.

6. An apparatus for measuring a signal, comprising:

an input operable to receive an input signal;

a controller coupled to the input and operable to:

set a gain numerator of a gain value using a gain numerator signal; and

set a gain denominator of the gain value using a gain denominator signal, the gain value comprising a ratio of the gain numerator to the gain denominator; and

a gain amplifier coupled to the controller and operable to adjust the input signal in accordance to the gain value to yield an output signal, the controller being operable to:

determine whether the output signal is within or outside of a threshold range;

measure the input signal according to the output signal and a reciprocal of the gain value, the reciprocal comprising a ratio of the gain denominator to the gain numerator: and

adjust the gain value in accordance with the determination of whether the output signal is within or outside of the threshold range by performing at least one of the following:

adjusting the gain numerator signal; and

adjusting the gain denominator signal.

7. The apparatus of claim 6 , wherein the controller is operable to measure the input signal according to the output signal and the reciprocal of the gain value by:

determining that the output signal is outside of the threshold range; and

reporting that the output signal is outside of the threshold range.

8. The apparatus of claim 6 , wherein the controller is operable to measure the input signal according to the output signal and the reciprocal of the gain value by:

determining that the output signal is within the threshold range; and

calculating the input signal by multiplying the reciprocal of the gain value and the output signal.

9. The apparatus of claim 6 , wherein the controller is operable to:

set the gain numerator of the gain value by setting a first resistance of the gain amplifier; and

set the gain denominator of the gain value by setting a second resistance of the gain amplifier.

10. The apparatus of claim 6 , wherein the controller is operable to:

set the gain denominator of the gain value by setting a first capacitance of a gain amplifier; and

set the gain numerator of the gain value by setting a second capacitance of the gain amplifier.

11. Logic for measuring a signal, the software embodied in a medium and operable to:

set a gain numerator of a gain value using a gain numerator signal;

set a gain denominator of the gain value using a gain denominator signal, the gain value comprising a ratio of the gain numerator to the gain denominator;

receive an input signal;

adjust the input signal in accordance to the gain value to yield an output signal;

determine whether the output signal is within or outside of a threshold range;

measure the input signal according to the output signal and a reciprocal of the gain value, the reciprocal comprising a ratio of the gain denominator to the gain numerator; and

adjust the gain value in accordance with the determination of whether the output signal is within or outside of the threshold range by performing at least one of the following:

adjusting the gain numerator signal; and

adjusting the gain denominator signal.

12. The logic of claim 11 , operable to measure the input signal according to the output signal and the reciprocal of the gain value by:

determining that the output signal is outside of the threshold range; and

reporting that the output signal is outside of the threshold range.

13. The logic of claim 11 , operable to measure the input signal according to the output signal and the reciprocal of the gain value by:

determining that the output signal is within the threshold range; and

calculating the input signal by multiplying the reciprocal of the gain value and the output signal.

14. The logic of claim 11 , operable to:

set the gain numerator of the gain value by setting a first resistance of a gain amplifier; and

set the gain denominator of the gain value by setting a second resistance of the gain amplifier.

15. The logic of claim 11 , operable to:

set the gain denominator of the gain value by setting a first capacitance of a gain amplifier; and

set the gain numerator of the gain value by setting a second capacitance of the gain amplifier.

16. A system for measuring a signal, comprising:

means for setting a gain numerator of a gain value using a gain numerator or signal;

means for setting a gain denominator of the gain value using a gain denominator signal, the gain value comprising a ratio of the gain numerator to the gain denominator;

means for receiving an input signal;

means for adjusting the input signal in accordance to the gain value to yield an output signal;

means for determining whether the output signal is within or outside of a threshold range.

means for measuring the input signal according to the output signal and a reciprocal of the gain value, the reciprocal comprising a ratio of the gain denominator to the gain numerator; and

means for adjusting the gain value in accordance with the determination of whether the output signal is within or outside of the threshold range by performing at least one of the following:

adjusting the gain numerator signal; and

adjusting the gain denominator signal.

17. A method for measuring a signal, comprising:

setting a gain numerator of a gain value by setting a first resistance or a first capacitance of a gain amplifier;

setting a gain denominator of the gain value by setting a second resistance or a second capacitance of the gain amplifier, the gain value comprising a ratio of the gain numerator to the gain denominator;

receiving an input signal;

adjusting the input signal in accordance to the gain value to yield an output signal;

measuring the input signal according to the output signal and a reciprocal of the gain value, the reciprocal comprising a ratio of the gain denominator to the gain numerator, by determining whether the output signal is outside of a threshold value, by reporting that the output signal is outside of the threshold value if the output signal is outside of the threshold value, and by calculating the input signal by multiplying the reciprocal of the gain value; and the output signal if the output signal is within the threshold value; and

adjusting a value selected from a group, the group consisting of the am numerator and the gain denominator, in response to the measurement of the input signal.