Method and arrangement for a power amplifier

• US 20040196899A1
• Filed: 04/14/2004
• Published: 10/07/2004
• Est. Priority Date: 10/15/2001
• Status: Active Grant

• Current Assignee: Telefonaktiebolaget LM Ericsson
• Original Assignee: Telefonaktiebolaget LM Ericsson
• Inventors: Faulkner, Michael, Zhou, Shu-Ang
• Granted Patent: US 7,095,277 B2
• Time in Patent Office: Days
• US Class Current: 375/238
• CPC Class Codes: H03F 1/32 Modifications of amplifiers to reduce non-linear distortion by negative feedback H03F1/34
• CPC Class Codes: H03F 2200/331 Sigma delta modulation being used in an amplifying circuit
• CPC Class Codes: H04B 1/0483 Transmitters with multiple parallel paths

Abstract

The present invention relates to an arrangement and a method for amplifying high frequency RF signals having amplitude and phase variations. The objective problem of the present invention is to provide an efficient power amplifier for amplifying high frequency RF signals. The object is achieved by introducing a Signal Conditioning Device (SCD) that converts baseband signals SI and SQ into tri-states signals STI, STQ. The tri-states signals STI, STQ are time multiplexed, which results in that a single power amplifier can be used to amplify the signal on the In-phase (I) channel and the signal on the Quadrature (Q) channel. Hence, the present invention does not require a power combiner.

Claims

1. Power amplifier device comprising means for amplifying a high frequency signal having both amplitude and phase variations,

means for separating said signal into an In-phase (I) component signal (S_I) and into a Quadrature (Q) component signal (S_Q),

said power amplifier device is characterised in that

it comprises a Signal Conditioning Device, SCD, comprising:

means for generating an n-state level I component signal (S_TI) from said I component signal (S_I),

means for generating an n-state level Q component signal (S_TQ) from said Q component signal (S_Q), and

means for interleaving the n-state level I component signal and the n-state level Q component signal into, a non-overlapping in time, I component signal (S_TI) and Q component signal (S_TQ);

a multiplexing device comprising means for generating a signal (S_MIQ) with a high frequency carrier wave wherein the I and Q components are being time multiplexed; and

a single Power Amplifier, PA, comprising means for amplifying said signal (S_MIQ).

2. Power amplifier device according to claim 1, wherein the single PA is a Non-Linear PA, NLPA.

3. Power amplifier device claim 1, wherein it comprises means for Pulse-Width Modulating, PWM, the I component signal (S_TI) and Q component signal (S_TQ).

4. Power amplifier device claim 1, wherein it comprises:

means for multiplying the I component signal (S_TI) with the I component of a high frequency carrier wave within a first multiplexing device (MI),

means for multiplying the Q component signal (S_TQ) with the Q component of a high frequency carrier wave within a second multiplexing device (MQ), and

means for the I component signal (S_TI) for controlling the first multiplexing device (MI), and

means for the Q component signal (S_TQ) for controlling the second multiplexing device (MQ) in order to time multiplex the respective I component signal (S_TI) and Q component signal, (S_TQ).

5. Power amplifier device according to claim 4, wherein it comprises means for amplifying said carrier wave before any of the components of said carrier wave entering any of the multiplexing devices (MI;

MQ).

6. Power amplifier device according to claim 4, wherein n is equal to three and MI and MQ respectively, comprising a three-throw switch.

7. Power amplifier device according to claim 1, wherein it comprises:

means for transferring the I component signal (S_TI) and the Q component signal (S_TQ) into a translation unit, and

means for transferring a control signal S_c from said translation unit into an n-throw switch (MC),

means for transferring a carrier wave into said n-throw-switch and obtaining an output signal (S_MIQ) from said n-throw switch (MC).

8. Power amplifier device according to claim 1, wherein it comprises means for connecting a predistortor unit in order to compensate for any non-linearities and/or other errors during the amplification process.

9. Method for amplifying a high frequency signal having both amplitude and phase variations, comprising the step of:

separating said signal into an In-phase (I) component signal (S_I) and into a Quadrature (Q) component signal (S_Q),

characterised by the method comprising the further steps of;

generating an n-state level I component signal from said I component signal (S_I),

generating an n-state level Q component signal from said Q component signal (S_Q),

interleaving the n-state level I component signal and the n-state level Q component signal into, a non-overlapping in time, I component signal (S_TI) and Q component signal (S_TQ);

generating a signal (S_MIQ) with a high frequency carrier wave wherein the I and Q components are being time multiplexed and

amplifying said signal (S_MIQ) using a single Power Amplifier, PA.

10. Mthod according to claim 9, wherein the PA is a Non-Linear PA.

11. Method according to claim 9, comprising the further step of:

Pulse-Width Modulating, PWM, the I component signal (S_TI), and the Q component signal (S_TQ), respectively.

12. Method according to claim 9, comprising the further steps of:

multiplying the I component signal (S_TI) with the I component of a high frequency carrier wave within a first multiplexing device (MI),

multiplying the Q component signal (S_TQ) with the Q component of a high frequency carrier wave within a second multiplexing device (MQ), and the I component signal (S_TI)

controlling the first multiplexing device (MI) and the Q component signal (S_TQ),

controlling the second multiplexing device (MQ) in order to time multiplex the respective I and Q component signal (S_TI, S_TQ).

13. Method according to claim 12, comprising the further step of:

amplifying said carrier wave before any of the components of said carrier wave entering any of the multiplexing devices (MI;

MQ).

14. Method according to claim 12, wherein n is equal to three and MI and MQ respectively, comprising a three-throw switch.

16. Method according to claim 9, comprising the further step of:

connecting a predistortor unit in order to compensate for any non-linearities and/or other errors during the amplification process.

15. Method according to clai 9, comprising the further steps of:

transferring the I component signal (S_TI) and the Q component signal (S_TQ) into a translation unit, and

transferring a control signal S_c from said translation unit into an m-throw switch (MC),

transferring a carrier wave into said n-throw-switch and obtaining an output signal (S_MIQ) from said n-throw switch (MC).