Method and system for crest factor reduction

• US 10,084,494 B2
• Filed: 07/11/2017
• Issued: 09/25/2018
• Est. Priority Date: 01/03/2014
• Status: Active Grant

• Current Assignee: Maxlinear Incorporated
• Original Assignee: Maxlinear Incorporated
• Inventors: Sridhar, Ramesh, Gallagher, Timothy, Swaroop, Shantha Murthy Prem, ghadam, Ali Shahed hagh
• Primary Examiner(s): Lee, Siu
• Application Number:
  US15/646,773
• Publication Number:
  US 20170310347A1
• Time in Patent Office: 441 Days
• Field of Search: 375295, 375296, 375297
• CPC Class Codes: H03F 1/02 Modifications of amplifiers to raise the efficiency, e.g. gliding Class A stages, use of an auxiliary oscillation
• CPC Class Codes: H03F 1/3241 using predistortion circuits H03F1/3211, H03F1/3217 take precedence
• CPC Class Codes: H03F 1/3247 using feedback acting on predistortion circuits H03F1/3264 takes precedence
• CPC Class Codes: H03F 2200/451 the amplifier being a radio frequency amplifier
• CPC Class Codes: H03F 2201/3215 To increase the output power or efficiency
• CPC Class Codes: H03F 3/195 in integrated circuits
• CPC Class Codes: H03F 3/213 in integrated circuits
• CPC Class Codes: H03F 3/24 of transmitter output stages
• CPC Class Codes: H03G 3/3042 in modulators, frequency-changers, transmitters or power amplifiers transmission power control in bidirectional transmission systems H04W52/04
• CPC Class Codes: H04B 1/0475 with means for limiting noise, interference or distortion H04B1/0483 takes precedence
• CPC Class Codes: H04B 2001/0425 with linearisation using predistortion
• CPC Class Codes: H04B 2001/045 with means for improving efficiency

Abstract

Methods and systems for crest factor reduction may comprise generating an original waveform, generating a distortion signal by reducing a crest factor of the original waveform, generating an error signal by subtracting out the original waveform from the distortion signal, and generating a conditioned waveform by adding the error signal to the original waveform. The crest factor of the original waveform may be reduced based on spectral mask requirements. The crest factor of the original waveform may be reduced using a limiter. The power amplifier may comprise a programmable gain amplifier (PGA). The distortion signal may be generated based on a PGA model and/or a predistortion model. A signal from an output of the PA may be fed back to the PGA model. The PGA model may be dynamically configured. The crest factor of the original waveform may be reduced in an analog domain and/or a digital domain.

Claims

1. A method for communication, the method comprising:

communicating an input signal to a programmable gain amplifier (PGA);

generating a distortion signal utilizing a PGA model that predicts an output signal of the PGA based on the input signal;

generating an error signal by subtracting out the input signal from the distortion signal;

filtering the generated error signal; and

generating a conditioned waveform with crest factor reduced from that of the input signal by adding the filtered error signal to the input signal.

2. The method according to claim 1, comprising reducing the crest factor of the input signal based on spectral mask requirements.

3. The method according to claim 1, comprising iterating the generating of the conditioned waveform.

4. The method according to claim 1, comprising generating the distortion signal based on a predistortion model.

5. The method according to claim 4, comprising feeding back a signal from an output of the PGA to the predistortion model.

6. The method according to claim 4, comprising dynamically configuring the predistortion model.

7. The method according to claim 1, comprising reducing the crest factor of the input signal in an analog domain.

8. The method according to claim 1, comprising reducing the crest factor of the input signal in a digital domain.

9. The method according to claim 1, comprising filtering the error signal utilizing a distortion shaping filter.

10. A system for communication, the system comprising:

one or more circuits of a transmitter, said one or more circuits being operable to;

communicate an input signal to a programmable gain amplifier (PGA) for subsequent transmission;

generate a distortion signal utilizing a PGA model that predicts an output signal of the PGA based on the input signal;

generate an error signal by subtracting the input signal from the distortion signal;

filter the generated error signal; and

generate a conditioned waveform with crest factor reduced from that of the input signal by adding the filtered error signal to the input signal.

11. The system according to claim 10, wherein said one or more circuits are operable to reduce the crest factor of said input signal based on spectral mask requirements.

12. The system according to claim 10, wherein said one or more circuits are operable to iterate the generating of the conditioned waveform.

13. The system according to claim 10, wherein said one or more circuits are operable to generate the distortion signal based on a predistortion model.

14. The system according to claim 13, wherein said one or more circuits are operable to feed back a signal from an output of the PGA to the predistortion model.

15. The system according to claim 13, wherein said one or more circuits are operable to dynamically configure the predistortion model.

16. The system according to claim 10, wherein said one or more circuits are operable to reduce the crest factor of the input signal in an analog domain.

17. The system according to claim 10, wherein said one or more circuits are operable to filter the error signal utilizing a distortion shaping filter.

18. A method for communication, the method comprising:

generating an input signal be amplified by a programmable gain amplifier (PGA);

generating a distortion signal utilizing a PGA model that predicts an output signal of the PGA based on the input signal;

generating an error signal by subtracting out the input signal from the distortion signal;

filtering the error signal utilizing a distortion shaping filter; and

generating a conditioned waveform with crest factor reduced from that of the input signal by adding the filtered error signal to the input signal.

19. The method according to claim 18, comprising reducing the crest factor of the input signal based on spectral mask requirements.

20. The method according to claim 18, comprising iterating the generating of the conditioned waveform.