Automatic transmit power control loop

1. A system, comprising:

a transmitter including a power amplifier; and

a power controller adapted to receive a coupler value of a power level at said output of said power amplifier if said power level is above a predetermined low power threshold and, if the coupler value is not equal to a set value, adjust a control value until the coupler value substantially equals the set value; and perform a low power extrapolation if said power level is below a predetermined threshold.

2. A system in accordance with claim 1 , an output of said power controller adapted to control a setting of said power amplifier.

3. A method for use in a telecommunications transmitter, comprising:

initializing low power threshold, nominal transmit power, coupler, and transmit DAC values;

specifying a set power level;

setting a transmit DAC with a nominal transmit DAC value corresponding to said set power level;

reading an output of a power coupler and determining a power coupler value after said transmit DAC is set with said nominal transmit DAC value;

comparing said power coupler value to a nominal power coupler value;

adjusting said transmit DAC such that said power coupler value substantially matches said nominal power coupler value if said set power level is greater than said low power threshold;

extrapolating past transmit DAC values to set said transmit DAC if said set power level is less than said low power threshold.

4. A method in accordance with claim 3 , wherein said threshold defines a linear region of a coupler vs. transmit power response.

5. A radio transmitter system, comprising:

a transmitter having a variable gain amplifier; and

means for adjusting a gain level of said variable gain amplifier, said adjusting means configured to receive a coupler value corresponding to a power level at an output of said variable gain amplifier if said power level is greater than a predetermined low power threshold and, if the coupler value is not equal to a set value, adjusting said pain level until the coupler value substantially equals the set value, and

means operably coupled to the gain level adjusting means for extrapolating a low power pain level if said power level is less than said predetermined low power threshold.

6. A radio transmitter system in accordance with claim 5 , said adjusting means further including a slope calculation unit adapted to provide a power curve value to said extrapolating means if a power measurement is less than said predetermined threshold.

7. A system, comprising:

a transmitter including a power amplifier configured to receive an initial set power level; and

a power controller configured to adjust an output of said power amplifier based on a low power extrapolation of a power measurement if said set power level is below a predetermined low power threshold and adjust said output based on said power measurement until an output coupler value corresponds to a nominal value if said set power level is above said predetermined low power threshold.

8. A system in accordance with claim 7 , wherein said low power extrapolation is derived from a past values on a power curve.

9. A system comprising:

a transmitter including a power amplifier;

a level detector configured to compare a set power level with a low power threshold;

a power controller configured to adjust an output of said power amplifier based on a low power extrapolation of a coupler output if said set power level is below said low power threshold and adjust an output of said power amplifier until said coupler output corresponds to a nominal value if said set power level is above said predetermined threshold.

10. A system In accordance with claim 9 , wherein said power controller is adapted to adjust a gain level of a power amplifier.

11. A system in accordance with claim 10 , wherein determining said extrapolation comprises determining a value of an output power curve using past measured values of said output power.

12. A telecommunications device, comprising:

a transmitter including a power amplifier controlled via a transmit DAC;

a level detector adapted to compare a power level with respect to a low power threshold;

a power controller adapted to adjust a value of said transmit DAC based on a low power extrapolation of a coupler output if said power level is below said low power threshold; and

wherein said power controller is adapted to adjust a value of said transmit DAC based on said output of said power coupler if said set power level is above said low power threshold until a coupler value is substantially equal to said power level.

13. A system, comprising:

a transmitter including a power amplifier; and

means configured to receive a coupler value of a power level at said output of said power amplifier if said power level is above a predetermined low power threshold and, if the coupler value is not equal to a set value, adjusting a control value until the coupler value substantially equals the set value; and performing a low power extrapolation if said power level is below a predetermined threshold.