Multi-band predistorter using power series representation

1. A multi-band predistorter using power series representation for compensating for distortions genreated by a power amplifier, said predistorter comprising:

dividing means for dividing input signals of multiple frequency bands and providing the divided input signals to a linear signal transfer path and a plurality of distortion generation paths for a plurality of frequency bands;

combining means for combining outputs from said linear signal transfer path and from said plurality of distortion generation paths; and

a delay circuit provided in said linear signal transfer path;

wherein each of said plurality of distortion generation paths includes:

a band signal extractor for extracting a signal of corresponding one of said plurality of frequency bands from said divided input signals provided to said each distortion generation path; and

a distortion generator supplied with said extracted signal, for generating at least one of odd-order distortion components of said extracted signal as an output from said each band-specific distortion generation path.

2. The multi-band predistorter using power series representaion of claim 1 , further comprising a vector adjuster provided at an output side of said distortion generator of said each distortion generation path, for adjusting a phase and an amplitude of said at least one odd-order distortion component, and for providing said adjusted odd-order distortion component as the output from said each distortion generation path.

3. The multi-band predistorter using power series representation of claim 1 , wherein said band signal extractor is a band pass filter.

4. The multi-band predistorter using power series representation of claim 1 , wherein said band signal extractor is a band elimination filter.

5. The multi-band predistorter using power series representation of claim 1 , wherein said each distortion generation path includes:

a plurality of distortion generators supplied with said extracted signal, for generating a plurality of different odd-order distortion components;

a plurality of vector adjusters for adjusting amplitudes and phases of the output signals from said plurality of distortion generators; and

a second combiner for combining adjusted outputs from said plurality of vector adjusters into the output from said each band-specific distortion generation path.

6. The multi-band predistorter using power series representation of any one of claims 2 to 5 , wherein said vector adjusters are each formed by a cascade connection of a variable attenuator and a variable phase shifter.

7. The multi-band predistorter using power series representation of any of claims 1 to 5 is implemented by digital signal processing.

8. The multi-band predistorter using power series representation of any of claims 1 to 5 is implemented by analog signal processing.

9. The multi-band predistorter using power series representation of claim 2 or 5 , further comprising:

signal detecting means for detecting distortion components of said plurality of frequency bands from an output signal of said power amplifier; and

control means supplied with said distortion components of said plurality of frequency bands, for controlling said vector adjusters corresponding to said plurality of frequency bands, respectively.

10. The multi-band predistorter using power series representation of claim 9 , wherein:

said signal detecting means includes a plurality of signal detectors for detecting signal components of said plurality of frequency bands from the output signal of said power amplifier; and

said control means includes a plurality of controllers for controlling said plurality of vector adjusters corresponding to said plurality of frequency bands, respectively, on a basis of the extracted signal components of said plurality of frequency bands.

11. The multi-band predistorter using power series representation of claim 9 , wherein:

said signal detecting means includes one signal detector for detecting signal components of said plurality of frequency bands from the output signal of said power amplifier; and

said control means includes one controller for controlling said plurality of vector adjusters corresponding to said plurality of frequency bands, respectively on a basis of the detected signal components of said plurality of frequency bands.

12. The multi-band predistorter using power series representation of claim 9 , wherein:

said signal detecting means includes a plurality of signal detectors for detecting signal components of said plurality of frequency bands from the output signal of said power amplifier; and

said control means includes a plurality of controllers for controlling said plurality of vector adjusters corresponding to said plurality of frequency bands, respectively, on a basis of the detected signal components of said plurality of frequency bands.

13. The multi-band predistorter using power series representation of claim 9 , further comprising signal generating means for generating a plurality of pilot signals of said plurality of frequency bands, and signal injecting means for injecting said plurality of pilot signals into said divider.

14. The multi-band predistorter using power series representation of claim 13 , wherein:

said signal generating means generates for each frequency band two CW signals of different frequencies; and

said signal detecting means detects the two CW signals of different frequencies generated by said signal generating means.

15. The multi-band predistorter using power series representation of claim 13 , wherein:

said signal generating means generates for each frequency band a modulated signal; and

said signal detecting means detects the modulated signal generated by said signal generating means.

16. The multi-band predistorter using power series representation of claim 9 , wherein said signal detecting means detects a distortion component of a transmission signal.

17. The multi-band predistorter using power series representation of claim 9 , wherein said control means controls said plurality of vector adjusters in such manner as to minimize an output from said signal detecting means.

18. The multi-band predistorter using power series representation of claim 9 , wherein said control means simultaneously controls said plurality of vector adjusters in such manner as to minimize an output from said signal detecting means.

19. The multi-band predistorter using power series representation of claim 9 , wherein said control means controls said plurality of vector adjusters on a one-by-one basis in such manner as to minimize an output from said signal detecting means.