Low voltage transmitter
View Patent ↗A wireless communications transmitter is divided into N binary weighted communication signal processing paths including both fixed and variable gain communication signal processing chains. Specific bit sequences are used to select a combination of fixed and variable gain signal processing paths to adjust to a desired transmitter output power. Alternately, high and low power communication signal processing paths are chosen as needed with the high power communication signal processing path including an odd order harmonic notch filter.
1. A method in a wireless communications transmitter comprising:
determining a desired transmitter output power;
selecting from N binary weighted communication signal processing paths a first one or a first combination of paths including fixed gain communication signal processing;
selecting from the N binary weighted communication signal processing paths a second path including variable gain communication signal processing; and
wherein power used during collective processing of communication signals through a combination of the selected first one or first combination of paths and the second path substantially equals the desired transmitter output power.
2. The method of claim 1 , wherein the weighting of the N binary weighted communication signal processing paths comprises scaling of one or more circuit components located within the N binary weighted communication signal processing paths.
3. The method of claim 1 , wherein the selecting the first one or the first combination of paths provides course power tuning and the selecting of the second path provides fine power tuning.
4. The method of claim 3 , wherein the fine power tuning further comprises selecting a specific setting for a variable power amplifier driver located within the second path.
5. A wireless communications transmitter comprising:
N binary weighted communication signal processing paths comprising:
a first group of communication signal processing paths including a plurality of fixed gain communication signal processing chains;
a second communication signal processing path including a variable gain communication signal processing chain; and
a processor coupled to the N binary weighted communication signal paths, the processor configured to select, based on a desired transmission output power, one or more communication signal processing paths from the first group and additionally the second communication signal processing path to collectively process communication signals for transmission.
6. The wireless communications transmitter of claim 5 , wherein a fixed gain differs for one or more of the plurality of fixed gain communication signal processing chains.
7. The wireless communications transmitter of claim 5 , wherein a value of a fixed gain for each of the plurality of fixed gain communication signal processing chains is based on a weighting of the N binary weighted communication signal paths.
8. The wireless communications transmitter of claim 7 , wherein the weighting comprises scaling of one or more circuit components located within the N binary weighted communication signal processing paths.
9. The wireless communications transmitter of claim 5 , wherein the plurality of fixed gain communication signal processing chains each comprise a sequentially coupled input buffer, up-converter and power amplifier driver.
10. The wireless communications transmitter of claim 5 , wherein the variable gain communication signal processing chain comprises a sequentially coupled input buffer, up-converter and variable gain power amplifier driver.
11. The wireless communications transmitter of claim 5 , wherein the processor configured to select comprises a selection bit sequence for: selecting the one or more communication signal processing paths from the first group; selecting the additional second communication signal processing path; and selection of a gain for the variable gain communication signal processing chain.
12. The wireless communications transmitter of claim 11 , wherein most significant bits (MSBs) of the selection bit sequence provide course power tuning and least significant bits (LSBs) provide fine power tuning.
13. The wireless communications transmitter of claim 12 , wherein the fine power tuning further comprises selecting a specific setting for a variable power amplifier driver located within the second communication signal processing path.
14. The wireless communications transmitter of claim 11 , wherein the selection bit sequence provides at least 6 dB of gain control per bit.
15. The wireless communications transmitter of claim 5 , wherein the N binary weighted communication signal processing paths comprise four paths; the plurality of fixed gain communication signal processing chains includes three paths and the variable gain communication signal processing chain includes one path.
16. The wireless communications transmitter of claim 15 , wherein weighting of the three paths comprises 1:2, 1:4 and 1:8 of the total transmitter output power, respectively and the weighting of the one path comprises up to 1:8 of the desired transmission output power.