Digital predistortion linearization for power amplifiers

• US 9,813,089 B2
• Filed: 02/15/2017
• Issued: 11/07/2017
• Est. Priority Date: 11/06/2014
• Status: Active Grant

• Current Assignee: GM Global Technology Operations LLC (General Motors Company)
• Original Assignee: GM Global Technology Operations LLC (General Motors Company)
• Inventors: Talty, Timothy J., Sovero, Emilio A., Ahmed, Mohiuddin, Baringer, Cynthia D., Li, James Chingwei, Kuan, Yen-Cheng, Pan, Hsuanyu
• Primary Examiner(s): GONZALES, APRIL GUZMAN
• Application Number:
  US15/433,964
• Publication Number:
  US 20170187401A1
• Time in Patent Office: 265 Days
• Field of Search: 4551143
• CPC Class Codes: H03F 3/24 of transmitter output stages
• CPC Class Codes: H03M 1/0673 using random selection of the elements with data-controlled random generator H03M1/0665
• CPC Class Codes: H03M 1/365 the voltage divider being a single resistor string
• CPC Class Codes: H03M 1/662 Multiplexed conversion systems
• CPC Class Codes: H03M 3/408 by the use of an LC circuit
• CPC Class Codes: H03M 3/424 the quantiser being a multiple bit one
• CPC Class Codes: H04B 1/0007 wherein the AD/DA conversion occurs at radiofrequency or intermediate frequency stage
• CPC Class Codes: H04B 1/0475 with means for limiting noise, interference or distortion H04B1/0483 takes precedence
• CPC Class Codes: H04B 1/1036 with automatic suppression of narrow band noise or interference, e.g. by using tuneable notch filters H04B1/123 takes precedence; filter circuits H03H
• CPC Class Codes: H04B 1/3822 specially adapted for use in vehicles H04B1/3827 takes precedence
• CPC Class Codes: H04B 1/40 Circuits
• CPC Class Codes: H04B 2001/0408 with power amplifiers
• CPC Class Codes: H04B 2001/0425 with linearisation using predistortion
• CPC Class Codes: H04B 2001/1063 using a notch filter
• CPC Class Codes: H04L 1/0071 Use of interleaving interleaving per se H03M13/27

Abstract

A cellular radio architecture that includes an RF transmitter having a digital signal processor, a digital-to-analog converter (DAC) module that converts digital bits from the processor to an analog signal, a tunable bandpass filter that removes frequencies in the analog signal outside of a frequency band of interest, and a power amplifier that amplifies the filtered analog signal. The architecture also includes a calibration feedback device that receives the amplified analog signal and provides a feedback signal to the processor for calibrating the digital signal to provide amplified amplifier pre-distortion. The processor employs a noise-shaping operation to shape the analog signal from the DAC to remove quantization noise in an immediate vicinity of the signal to improve signal-to-noise ratio, performs an infinite impulse response process to lower a noise floor in the analog signal, and provides pre-distortion of the digital signal to compensate for non-linearties of the power amplifier.

Claims

1. An RF transmitter module, said transmitter module comprising:

a digital signal processor (DSP) providing a digital signal to be transmitted;

a digital-to-analog converter (DAC) responsive to the digital signal from the DSP and a clock signal from a clock circuit, said DAC converting the digital signal to an analog signal;

a tunable bandpass filter responsive to the analog signal from the DAC and removing frequencies in the analog signal outside of a frequency band of interest; and

a power amplifier responsive to the filtered analog signal from the bandpass filter and amplifying the filtered analog signal, wherein the DSP employs a noise-shaping operation to shape the analog signal from the DAC to remove quantization noise in an immediate vicinity of the analog signal so as to improve signal-to-noise ratio.

2. The transmitter module according to claim 1 wherein the DSP performs an infinite impulse response process to lower a noise floor in the vicinity of the analog signal.

3. The transmitter module according to claim 1 wherein the DSP provides pre-distortion of the digital signal to compensate for non-linearities of the power amplifier.

4. The transmitter module according to claim 3 further comprising a calibration feedback device responsive to the amplified analog signal and providing a feedback signal to the DSP for calibrating the digital signal to provide the pre-distortion.

5. The transmitter module according to claim 1 wherein the DAC is a 4-bit DAC.

6. The transmitter module according to claim 1 wherein the DAC operates at a 5 GHz sample rate.

7. The transmitter module according to claim 1 wherein the bandwidth of the analog signal varies in the range of 20-100 MHz.

8. The transmitter module according to claim 1 wherein the DSP is implemented in CMOS.

9. The transmitter module according to claim 1 wherein the bandpass filter is an active filter.

10. The transmitter module according to claim 1 wherein the RF transmitter module is for a cellular radio.

11. The transmitter module according to claim 1 wherein the cellular radio is a vehicle cellular radio.

12. An RF transmitter module for a cellular radio, said transmitter module comprising:

a digital signal processer (DSP) providing a digital signal to be transmitted, said DSP being implemented in CMOS;

a digital-to-analog converter (DAC) responsive to the digital signal from the DSP and a clock signal from a clock circuit, said DAC converting the digital signal to an analog signal;

a tunable bandpass filter responsive to the analog signal from the DAC and removing frequencies in the analog signal outside of a frequency band of interest;

a power amplifier responsive to the filtered analog signal from the bandpass filter and amplifying the analog signal; and

a calibration feedback device responsive to the amplified analog signal and providing a feedback signal to the DSP, wherein the DSP provides pre-distortion of the digital signal to compensate for non-linearities of the power amplifier using the feedback signal.

13. The transmitter module according to claim 12 wherein the DSP employs a noise-shaping operation to shape the analog signal from the DAC to remove quantization noise in an immediate vicinity of the analog signal so as to improve signal-to-noise ratio.

14. The transmitter module according to claim 13 wherein the DSP performs an infinite impulse response process to lower a noise floor in the vicinity of the analog signal.

15. The transmitter module according to claim 12 wherein the DAC is a 4-bit DAC.

16. The transmitter module according to claim 12 wherein the DAC operates at a 5 GHz sample rate.

17. The transmitter module according to claim 12 wherein the bandwidth of the analog signal varies in the range of 20-100 MHz.

18. The transmitter module according to claim 12 wherein the cellular radio is a vehicle cellular radio.

19. An RF transmitter module for a cellular vehicle radio, said transmitter module comprising:

a digital signal processor (DSP) providing a digital signal to be transmitted;

a digital-to-analog converter (DAC) responsive to the digital signal from the DSP and converting the digital signal to an analog signal;

a tunable bandpass filter responsive to the analog signal from the DAC and removing frequencies in the analog signal outside of a frequency band of interest;

a power amplifier responsive to the filtered analog signal from the bandpass filter and amplifying the analog signal; and

a calibration feedback device responsive to the amplified analog signal and providing a feedback signal to the DSP, wherein the DSP provides pre-distortion of the digital signal to compensate for non-linearties of the power amplifier using the feedback signal, employs a noise-shaping operation to shape the analog signal from the DAC to remove quantization noise in an immediate vicinity of the analog signal so as to improve signal-to-noise ratio, and performs an infinite impulse response process to lower a noise floor in the vicinity of the analog signal.

20. The transmitter module according to claim 19 wherein the DAC is a 4-bit DAC.