Distortion compensator apparatus, amplifier apparatus, transmitter, and method of compensating distortion

• US 8,204,454 B2
• Filed: 05/29/2007
• Issued: 06/19/2012
• Est. Priority Date: 06/08/2006
• Status: Active Grant

• Current Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: Yamaoka, Atsushi, Yamaguchi, Keiichi
• Primary Examiner(s): Lam, Tuan T
• Application Number:
  US12/303,381
• Publication Number:
  US 20090195309A1
• Time in Patent Office: 1,848 Days
• Field of Search: None
• US Class Current: 455/114.2
• CPC Class Codes: H03F 1/3288 to compensate phase shift as a function of the amplitude
• CPC Class Codes: H03F 1/3294 Acting on the real and imaginary components of the input signal
• CPC Class Codes: H03F 2200/336 A I/Q, i.e. phase quadrature, modulator or demodulator being used in an amplifying circuit
• CPC Class Codes: H03F 2201/3233 Adaptive predistortion using lookup table, e.g. memory, RAM, ROM, LUT, to generate the predistortion

Abstract

This distortion compensator apparatus is a distortion compensator apparatus compensating nonlinearity of an amplifier and includes: a memory storing a compensation parameter used for correcting an input signal of the amplifier; a compensator correcting the input signal of the amplifier based on the compensation parameter; and an update controller updating the compensation parameter according to an operation state of the amplifier.

Claims

1. A distortion compensator apparatus for compensating nonlinearity of an amplifier, comprising:

a memory configured to store a first parameter used for correcting an amplitude component of an input signal of the amplifier and a second parameter used for correcting a phase component of the input signal;

a compensator configured to correct the amplitude component of the input signal based on the first parameter and to correct the phase component of the input signal based on the second parameter; and

an update controller configured to update at least one of the first and the second parameters according to an operation state of the amplifier and a plurality of update modes,

wherein the update modes include a first mode to only update the first parameter, a second mode to only update the second parameter, and a third mode to update both of the first and the second parameters, and

wherein said compensator comprises;

a first amplitude calculator configured to calculate an amplitude value of the input signal;

a real multiplier configured to perform real multiplication processing on the first parameter stored in said memory and the input signal, based on the amplitude value calculated by said first amplitude calculator;

a second amplitude calculator configured to calculate an amplitude value of a signal resulting from the real multiplication processing; and

a complex multiplier configured to perform complex multiplication processing on the second parameter stored in said memory and the signal resulting from the real multiplication processing, based on the amplitude value calculated by said second amplitude calculator.

2. The distortion compensator apparatus according to claim 1, further comprising a monitor signal generator configured to generate a monitor signal to indicate a characteristic of the amplifier by monitoring the operation state of the amplifier,

wherein said update controller updates at least one of the first and the second parameters based on the monitor signal.

3. The distortion compensator apparatus according to claim 2, wherein said monitor signal generator generates a signal to indicate at least one of output power of the amplifier, an adjacent channel leakage ratio of the amplifier, a gain occurring on a preceding stage of the amplifier, a phase difference occurring on the preceding stage of the amplifier, a temperature of the amplifier, and a frequency of the input signal, as the monitor signal.

4. The distortion compensator apparatus according to claim 1, further comprising a timer configured to output a timing signal to indicate a timing for updating the first and the second parameters, and

wherein said update controller updates at least one of the first and the second parameters based on the timing signal outputted by said timer.

5. An amplifier apparatus, comprising:

an amplifier;

a memory configured to store a first parameter used for correcting an amplitude component of an input signal of the amplifier and a second parameter used for correcting a phase component of the input signal in order to compensate nonlinearity of said amplifier;

a compensator configured to correct the amplitude component of the input signal based on the first parameter and to correct the phase component of the input signal based on the second parameter; and

an update controller configured to update at least one of the first and the second parameters according to an operation state of said amplifier and a plurality of update modes,

wherein the update modes include a first mode to only update the first parameter, a second mode to only update the second parameter, and a third mode to update both of the first and the second parameters, and

wherein said compensator comprises;

a first amplitude calculator configured to calculate an amplitude value of the input signal;

a real multiplier configured to perform real multiplication processing on the first parameter stored in said memory and the input signal, based on the amplitude value calculated by said first amplitude calculator;

a second amplitude calculator configured to calculate an amplitude value of a signal resulting from the real multiplication processing; and

a complex multiplier configured to perform complex multiplication processing on the second parameter stored in said memory and the signal resulting from the real multiplication processing, based on the amplitude value calculated by said second amplitude calculator.

6. The amplifier apparatus according to claim 5, further comprising a monitor signal generator configured to generate a monitor signal to indicate a characteristic of said amplifier by monitoring the operation state of said amplifier,

wherein said update controller updates at least one of the first and the second parameters based on the monitor signal.

7. A transmitter, comprising:

the amplifier apparatus according to claim 5; and

a modulator configured to modulate the input signal corrected by said compensator to input the modulated input signal to said amplifier.

8. A method of compensating distortion for compensating nonlinearity of an amplifier, comprising:

storing in a memory a first parameter used for correcting an amplitude component of an input signal of the amplifier and a second parameter used for correcting a phase component of the input signal;

correcting the amplitude component of the input signal based on the first parameter and the phase component of the input signal based on the second parameter; and

updating at least one of the first and the second parameters according to an operation state of the amplifier and a plurality of update modes,

wherein the update modes include a first mode to only update the first parameter, a second mode to only update the second parameter, and a third mode to update both of the first and the second parameters, and

wherein said correcting comprises;

calculating a first amplitude value of the input signal;

performing real multiplication processing on the first parameter stored in said memory and the input signal, based on the first amplitude value;

calculating a second amplitude value of a signal resulting from the real multiplication processing; and

performing complex multiplication processing on the second parameter stored in said memory and the signal resulting from the real multiplication processing, based on the second amplitude value.