Predistortion circuit for a transmit system

• US 7,953,378 B2
• Filed: 07/02/2008
• Issued: 05/31/2011
• Est. Priority Date: 07/03/2003
• Status: Expired due to Fees

• Current Assignee: Zarbana Digital Fund LLC (Intellectual Ventures LLC)
• Original Assignee: Zarbana Digital Fund LLC (Intellectual Ventures LLC)
• Inventors: Saed, Aryan
• Primary Examiner(s): Pan; Yuwen
• Application Number:
  US12/167,217
• Publication Number:
  US 20080268795A1
• Time in Patent Office: 1,063 Days
• Field of Search: 455/114.3, 455/115.1, 455/137, 455/143, 455/291, 455/293, 455/126, 330/136, 330/149
• US Class Current: 455/114.3
• CPC Class Codes: H03F 1/3247 using feedback acting on predistortion circuits H03F1/3264 takes precedence
• CPC Class Codes: H03F 2201/3233 Adaptive predistortion using lookup table, e.g. memory, RAM, ROM, LUT, to generate the predistortion
• CPC Class Codes: H04L 25/03343 Arrangements at the transmitter end
• CPC Class Codes: H04M 1/00 Substation equipment, e.g. for use by subscribers subscriber services or facilities provided at exchanges H04M3/00; prepayment telephone coin boxes H04M17/00; current supply arrangements H04M19/08

Abstract

Systems and methods related to amplifier systems which use a predistortion subsystem to compensate for expected distortions in the system output signal. A signal processing subsystem receives an input signal and decomposes the input signal into multiple components. Each signal component is received by a predistortion subsystem which applies a predistortion modification to the component. The predistortion modification may be a phase modification, a magnitude modification, or a combination of both and is applied by adjusting the phase of the fragment. The predistorted component is then separately processed by the signal processing subsystem. The processing may take the form of phase modulation and amplification. The phase modulated and amplified components are then recombined to arrive at an amplitude and phase modulated and amplified output signal. The predistortion modification is applied to the components to compensate for distortions introduced in the signal by the signal processing subsystem.

Claims

1. A system for processing an input signal, comprising:

means for decomposing the input signal into separate components to produce first and second phasor fragmentation signals;

means for producing a first and a second predistorted signals by applying a first and second deliberate predistortion to the first and second phasor fragmentation signals, respectively, responsive at least in part to the input signal; and

means for combining the first and second predistorted signals.

2. The system of claim 1, further comprising means for processing the first and second predistorted signals separately.

3. The system of claim 2, further comprising means for amplifying the first and second predistorted signals non-linearly.

4. The system of claim 2, further comprising a switch mode amplifier configured to amplify first and second predistorted signals.

5. The system of claim 1, further comprising means for adjusting a phase of an output signal by adjusting at least one of the first and second phasor fragmentation signals.

6. The system of claim 1, further comprising means for adjusting a magnitude of an output signal by adjusting first and second phasor fragmentation signals.

7. The system of claim 1, wherein each of the first and second phasor fragmentation signals comprises an angle.

8. The system of claim 1, further comprising means for looking up the deliberate predistortion in a table.

9. The system of claim 1, further comprising means for applying left or right triangle decomposition to the input signal.

10. The system of claim 1, wherein the means for producing the first and second predistorted signals applies the deliberate predistortion in response to a decomposition type used by the means for decomposing the input signal.

11. A method, comprising:

decomposing an input signal into separate components to produce at least two phasor fragmentation signals;

producing at least two predistorted signals by applying a first deliberate predistortion to a first of the at least two phasor fragmentation signals and a second deliberate predistortion to a second of the at least two phasor fragmentation signals to compensate for distortions in an output signal responsive to the input signal; and

combining the at least two predistorted signals to produce the output signal.

12. The method of claim 11, further comprising processing the at least two predistorted signals separately.

13. The method of claim 12, further comprising amplifying the at least two predistorted signals non-linearly.

14. The method of claim 12, further comprising using a switch mode amplifier to amplify the at least two predistorted signals.

15. The method of claim 11, further comprising adjusting a phase of the output signal by adjusting at least one of the at least two phasor fragmentation signals.

16. The method of claim 11, further comprising adjusting a magnitude of the output signal by adjusting at least one of the at least two phasor fragmentation signals.

17. The method of claim 11, wherein each of the at least two phasor fragmentation signals comprises an angle.

18. The method of claim 11, further comprising looking up the deliberate predistortion in a table.

19. The system method of claim 11, further comprising applying left or right triangle decomposition to the input signal.

20. A system, comprising:

a decomposition circuit configured to decompose an input signal into first and second internal signals;

a first predistortion circuit configured to generate a first predistortion signal by predistorting the first internal signal with a first deliberate predistortion in response to the input signal;

a second predistortion circuit configured to generate a second predistortion signal by predistorting the second internal signal with a second deliberate predistortion in response to the input signal; and

a combining circuit configured to combine the first predistortion signal with the second predistortion signal to generate an output signal;

wherein the first or second predistortion circuits, or a combination thereof, comprises a look-up table configured to be used to calculate the first or second deliberate predistortion, or a combination thereof.

21. The system of claim 20, wherein the first or second predistortion circuits, or a combination thereof, is configured to operate in response to a right or left triangle decomposition signal.

22. The system of claim 20, wherein the look-up table comprises:

a first sub-table with left triangle decomposition values; and

a second sub-table with right triangle decomposition values.

23. The system of claim 20, wherein the look-up table is configured to provide additive or multiplicative adjustment values as the first or second deliberate predistortion, or a combination thereof.

24. The system of claim 20, further comprising:

a first phase modulation circuit configured to modulate a phase of the first predistortion signal; and

a second phase modulation circuit configured to modulate a phase of the second predistortion signal.

25. The system of claim 24, further comprising:

a first amplifier configured to amplify an output of the first phase modulation circuit; and

a second amplifier configured to amplify an output of the second phase modulation circuit.

26. The system of claim 20, wherein the decomposition circuit comprises a phase fragmentation engine configured to deconstruct the input signal into the first and second internal signals having first and second phases, respectively.