Controller for an RF power amplifier
The controller controls the amplifier and a modulated power supply, supplying power to the amplifier, by detecting an RF envelope of a signal input to the amplifier. Predistortion of the amplifier synchronous with changes of bias is provided using a look-up table. Specifically, amplitude predistortion, phase predistortion and DC voltage level adjustments are made to the RF signal. Adjustments for gain and phase variation are applied synchronously with bias changes.
1. A controller for an RF amplifier, the controller comprising:
a power supply for supplying power to the RF amplifier; and
a control unit for detecting an RF envelope of a signal input to the RF amplifier includes a look-up table having correction values that are addressed based upon the detected RF envelope signal, wherein the control unit performs predistorition and controls the power supply based on the correction values; and
a micro-controller and interface for modifying the correction values in the look-up table without feedback.
2. The controller according to claim 1 , wherein the control unit is configured for controlling the power supply such that power output from the power supply is varied linearly.
3. The controller according to claim 1 , wherein the control unit adjusts the RF envelope signal to provide predistortion.
4. The controller according to claim 1 , wherein the control unit controls the power supply based upon the correction values and is synchronous with the predistortion.
5. The controller according to claim 4 , wherein the correction values comprise amplitude predistortion, phase predistortion and voltage correction values.
6. The controller according to claim 4 , wherein the control unit is configured to apply the correction values to the RF envelope.
7. The controller according to claim 1 , wherein the power supply is adjustable between a high voltage value and a low voltage value.
8. The controller according to claim 7 , wherein a voltage range between the high voltage value and the low voltage value is configurable based upon a setting of the low voltage value.
9. An RF amplifier, comprising:
a plurality of power stages providing power amplification;
a power supply for supplying power to the RF amplifier; and
a control unit for detecting an RF envelope of a signal input to the RF amplifier includes a look-up table having correction values that are addressed based upon the detected RF envelope signal, wherein the control unit performs predistorition and controls the power supply based on the correction values; and
a micro-controller and interface for modifying the correction values in the look-up table without feedback.
10. The RF amplifier according to claim 9 , wherein the plurality of power stages comprise a preamp stage, a driver stage and a power stage.
11. The RF amplifier according to claim 10 , wherein the control unit is configured for controlling power supplied to the driver stage and power stage.
12. The RF amplifier according to claim 9 , wherein the control unit adjusts the RF envelope signal to provide predistortion.
13. The RF amplifier according to claim 9 , wherein the control unit controls the power supply based upon the correction values and is synchronous with the predistortion.
14. The RF amplifier according to claim 13 wherein the correction values comprise amplitude, phase and voltage correction values.
15. The RF amplifier according to claim 13 , wherein the control unit is configured to apply the correction values to the RF envelope.
16. The RF amplifier according to claim 9 , wherein the power supply is adjustable between a high voltage value and a low voltage value.
17. The RF amplifier according to claim 16 , wherein a voltage range between the high voltage value and the low voltage value is configurable based upon a setting of the lower voltage value.
18. A method of controlling an RF amplifier, comprising:
detecting an RF envelope of a signal input to the RF amplifier;
addressing stored correction values based on the detected RF envelope signal; and
performing signal predistortion and controlling power supplied to the RF amplifier based on the correction values, wherein the correction values are modified without feedback.