Real-time digital phase and gain adaptation method using feedback and arrangement using such a method

• US 20070131078A1
• Filed: 11/22/2002
• Published: 06/14/2007
• Est. Priority Date: 11/22/2002
• Status: Abandoned Application

• Current Assignee: Telefonaktiebolaget LM Ericsson
• Original Assignee: Telefonaktiebolaget LM Ericsson
• Inventors: Kokkeler, Andre
• Application Number:
  US10/535,904
• Publication Number:
  US 20070131078A1
• Time in Patent Office: Days
• US Class Current: 84/1
• CPC Class Codes: H03F 1/3247 using feedback acting on predistortion circuits H03F1/3264 takes precedence
• CPC Class Codes: H03F 1/3282 Acting on the phase and the amplitude of the input signal

Abstract

Arrangement for real-time phase and gain adaptation as a function of frequency and gain adaptation as a function of amplitude of an input signal in relation to an output signal, the input signal having a first absolute phase and first power as a function of frequency, the output signal having a second absolute phase and second power as a function of frequency, the output signal, in use, being amplified relative to the input signal, the arrangement including a gain correction, and a power amplifier, the gain correction being arranged for receiving the input signal at a third input and a gain reference signal at the second input and for correcting the first power of the input signal, relative to the second power of the output signal, to form a predistorted outgoing signal and for outputting at the first output the predistorted outgoing signal, the gain reference signal having a gain value identical to the second power of the output signal relative to the first power of the input signal, wherein the arrangement includes a phase correction arranged for receiving the input signal at a third input and a phase reference signal at the second input and for correcting the first absolute phase of the input signal, relative to the second absolute phase of the output signal, as a function of frequency to form a phase-corrected outgoing signal and for outputting at the first output the phase-corrected outgoing signal, the phase reference signal having a phase value identical to the second absolute phase of the output signal relative to the first absolute phase of the input signal, the gain correction and the phase correction using a single feedback signal in the feedback path for deriving the gain reference signal and the phase reference signal, respectively.

Claims

1. An arrangement for correcting gain as a function of amplitude and of correcting frequency-dependent gain and phase for a device with a digital input signal and an analogue output signal, said arrangement comprising:

a gain correction block said gain correction block being connected at a first input for receiving an input signal, further being connected in a feedback path to an input of a power amplifier through a first output of said gain correction block and through a second input of said gain correction block to an output of said power amplifier;

said gain correction block being arranged for receiving said input signal at a third input and a gain reference signal at said second input and for correcting a first power of said input signal, relative to a second power of said output signal, to form a predistorted outgoing signal and for outputting said pre-distorted outgoing signal at said first output, said gain reference signal having a gain identical to said second power of said output signal relative to said first power of said input signal, and

a phase correction block said phase correction block being connected at a third input for receiving said input signal, said phase correction block being connected in said feedback path to said input of said power amplifier through a first output of said phase correction block, and through a second input of said phase correction block to said output of said power amplifier;

said phase correction block being arranged for receiving said input signal at a third input and a phase reference signal at said second input and for correcting said first absolute phase of said input signal, relative to said second absolute phase of said output signal, as a function of frequency to form a phase-corrected outgoing signal and for outputting at said first output said phase-corrected outgoing signal, said phase reference signal having a phase value identical to said second absolute phase of said output signal relative to said first absolute phase of said input signal,

said gain correction block and said phase correction block using a single feedback signal in said feedback path for deriving said gain reference signal and said phase reference signal, respectively.

2. The arrangement according to claim 1, wherein said input of said power amplifier comprises a digital-analogue- and up-converter, said digital-analogue- and up-converter is arranged in said feedback path between both said first outputs of said gain correction block and said phase correction block and said input of said power amplifier, and said analogue-digital converter being arranged in said feedback path between said output of said power amplifier and both said second inputs of said phase correction block and said gain correction block.

3. The arrangement according to claim 1, wherein said phase correction block is arranged for outputting at said second output a further output signal for transmission to said second input of said gain correction block as said gain reference signal.

4. The arrangement according to claim 1 wherein said gain correction block is arranged for outputting at said second output a further output signal for transmission to said second input of said phase correction block as said phase reference signal.

5. The arrangement according to claim 1, wherein said gain correction block comprises:

a digital predistortion block and an amplitude transfer estimation block,

said digital predistortion block comprising a further gain control input,

said amplitude transfer estimation block comprising a further gain control output,

said gain control output being connected to said gain control input,

said amplitude transfer estimation block being arranged for;

receiving said gain reference signal and for receiving at said third input said input signal, for comparing said input signal with said gain reference signal,

determining a gain control signal, and

outputting said gain control signal at said gain control output, and

said digital predistortion block being arranged for;

receiving said input signal at said third input and said gain control signal at said gain control input, and

correcting said first power of said input signal, relative to said second power of said output signal, as a function of amplitude, using said gain control signal.

6. The arrangement according to claim 1, wherein

said phase correction block comprises a phase adaptation block (9) and a phase estimation and correction block,

said phase adaptation block comprising a further phase control input,

said phase estimation and correction block comprising a further phase control output,

said phase control output being connected to said phase control input,

said phase estimation and correction block being arranged for:

receiving said phase reference signal and receiving at said third input said input signal, for comparing said input signal with said phase reference signal,

determining a phase control signal, and

outputting said phase control signal at said phase control output, and said phase adaptation block being arranged for;

receiving said input signal at said third input and said phase control signal at said phase control input, and

correcting said first absolute phase of said input signal, relative to said second absolute phase of said output signal, as a function of frequency, using said phase control signal.

7. The arrangement according to claim 5, wherein:

said phase adaptation block comprises a first digital Fourier transform processor (DFT), an inverse digital Fourier transform processor (IDFT), a corrector (CRT), and an adjuster (ADJ),

said digital Fourier transform processor (DFT) being connected to a first input of said corrector (CRT), said corrector (CRT) being connected at an output to an input of said inverse digital Fourier transform processor (IDFT), said adjuster (ADJ) being connected with an output to a second input of said corrector (CRT),

said digital Fourier transform processor (DFT) being arranged for;

receiving at an input said input signal and transforming said input signal as a Fourier transformed signal,

said adjuster (ADJ) being arranged for;

receiving at said phase control input said phase control signal, and at a second input a desired phase value of said phase as function of frequency and

determining an adjuster correction signal,

said corrector being arranged for;

receiving said Fourier transformed signal and said adjuster correction signal, and

determining and outputting a corrected Fourier transformed signal, and

said inverse digital Fourier transform processor (IDFT) being arranged for

receiving said corrected Fourier transformed signal and for determining and

outputting an inverse Fourier transform of said corrected Fourier transformed signal as said phase-corrected outgoing signal.

8. The arrangement according to claim 5, wherein said phase estimation and correction block comprises:

a cross-correlator (XC), a temporal processor (TP),

a second digital Fourier transform processor (DFT2), and

a spectral processor (SP),

said cross-correlator XC being connected at an output to an input of said temporal processor (TP), said temporal processor (TP) being connected at an output to an input of said second digital Fourier transform processor (DFT2), said second digital Fourier transform processor (DFT2) being connected at an output to an input of said spectral processor (SP), said spectral processor SP having said phase control output,

said cross-correlator (XC) being arranged for;

receiving on said second input said input signal and on said third input said phase reference signal,

determining, synchronising and cross-correlating said input signal and said phase reference signal into a cross-correlated signal, and

outputting said cross-correlated signal to said temporal processor (TP), said temporal processor (TP) being arranged for;

receiving said cross-correlated signal from said cross-correlator (XC),

adapting said cross-correlated signal into a modified cross-correlated signal adapted for a Fourier transform, and

outputting said modified cross-correlated signal to said second digital Fourier transform processor (DFT2),

said digital Fourier transform processor (DFT2) being arranged for;

receiving said modified cross-correlated signal,

computing a power spectrum signal from said modified cross-correlated signal, and

outputting a said power spectrum signal to said spectral processor (SP), and

said spectral processor (SP) being arranged for;

receiving said power spectrum signal,

determining at least an estimate of a phase as a function of frequency from said power spectrum signal as a phase-frequency signal, and

outputting said phase-frequency signal as said phase control signal to said phase adaptation block.

9. A method for real-time phase and gain adaptation as a function of frequency and gain adaptation as a function of amplitude of an input signal in relation to an output signal, said input signal having a first absolute phase and first power as a function of frequency, said output signal having a second absolute phase and second power as a function of frequency, said output signal, in use, being amplified relative to said input signal,

said method comprising a gain correction and a phase correction;

said gain correction comprising;

receiving said input signal and a gain reference signal from a feedback path,

correcting said first power of said input signal, relative to said second power of said output signal, into a predistorted outgoing signal, and

outputting said predistorted outgoing signal, said gain reference signal having a gain value identical to said second power of said output signal relative to said first power of said input signal, and;

said phase correction comprising;

receiving said input signal and a phase reference signal from said feedback path,

correcting said first absolute phase of said input signal, relative to said second absolute phase of said output signal, as a function of frequency into a phase-corrected outgoing signal, and

outputting said phase-corrected outgoing signal, said phase reference signal having a phase value identical to said second absolute phase of said output signal relative to said first absolute phase of said input signal,

wherein said gain correction and said phase correction are using a single feedback signal in said feedback path for deriving said gain reference signal and said phase reference signal, respectively.

10. A computer program product for correcting gain as a function of amplitude and of correcting frequency-dependent gain and phase for a device with a digital input signal and an analogue output signal, said computer program product comprising:

instructions in a computer readable media for said gain correction comprising;

instructions for receiving said input signal and a gain reference signal from a first feedback loop,

instructions for correcting said first power of said input signal, relative to said second power of said output signal, as a function of frequency into a predistorted outgoing signal, and

instructions for outputting said predistorted outgoing signal, said gain reference signal having a gain value identical to said second power of said output signal relative to said first power of said input signal, and

instructions in the computer readable media for said phase correction comprising;

instructions for receiving said input signal and a phase reference signal from said feedback path,

instructions for correcting said first absolute phase of said input signal, relative to said second absolute phase of said output signal, as a function of frequency into a phase-corrected outgoing signal, and

instructions for outputting said phase-corrected outgoing signal, said phase reference signal having a phase value identical to said second absolute phase of said output signal relative to said first absolute phase of said input signal,

wherein said gain correction and said phase correction are using a single feedback signal in said feedback path for deriving said gain reference signal and said phase reference signal, respectively.

11. (canceled)