Predistortion circuit and power amplifier

• US 20010013809A1
• Filed: 01/31/2001
• Published: 08/16/2001
• Est. Priority Date: 02/03/2000
• Status: Active Grant

• Current Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Inventors: Matsuura, Toru, Sakakura, Makoto, Ishida, Kaoru, Fujiwara, Seiji
• Granted Patent: US 6,933,780 B2
• Time in Patent Office: Days
• US Class Current: 330/149
• CPC Class Codes: H03F 1/3276 using the nonlinearity inherent to components, e.g. a diode

Abstract

A predistortion circuit has

an input terminal for inputting a predetermined signal;

a nonlinear device directly or indirectly connected to the input terminal;

a bias supply circuit for applying a voltage to the nonlinear device;

specific-frequency suppressing means connected to one side or both sides of the nonlinear device directly without another intervening device and of suppressing all or part of such frequencies that are from a frequency corresponding to DC to a frequency corresponding to an occupied band width of an input signal inputted to the input terminal and/or suppressing at least one higher harmonic frequency of a carrier wave of the input signal; and

an output terminal for outputting a signal.

Claims

1. A predistortion circuit comprising:

an input terminal for inputting a predetermined signal;

a nonlinear device directly or indirectly connected to said input terminal;

a bias supply circuit for applying a voltage to said nonlinear device;

specific-frequency suppressing means connected to one side or both sides of said nonlinear device directly without another intervening device and of suppressing all or part of such frequencies that are from a frequency corresponding to DC to a frequency corresponding to an occupied band width of an input signal inputted to said input terminal and/or suppressing at least one higher harmonic frequency of a carrier wave of said input signal; and

an output terminal for outputting a signal.

2. A predistortion circuit of

claim 1

, wherein said specific-frequency suppressing means has such impedance that the impedance of said specific-frequency suppressing means viewed from the connection point to which said specific- frequency suppressing means is connected is lower than the impedance of said nonlinear device viewed from said connection point at all or part of such frequencies that are from said frequency corresponding to DC to said frequency corresponding to said occupied bandwidth and/or at least one higher harmonic frequency of a carrier wave of said input signal.

3. Apredistortion circuit of

claim 1

, wherein said nonlinear device is provided between the connection point between said input terminal and said output terminal and the ground.

4. A predistortion circuit of

claim 1

, wherein said nonlinear device is connected between said input terminal and said output terminal.

5. Apredistortion circuit of

claim 1

, wherein:

said nonlinear device is a transistor;

said input terminal is connected to any one of the drain and the source of said transistor;

said output terminal is connected to the other of the drain and the source of said transistor; and

said bias supply circuit is connected to the gate of said transistor.

6. Apredistortion circuit of any one of

claims 1

to

5

, wherein said specific-frequency suppressing means comprises the all or a part of a resistor, a coil, a capacitor, and a transmission line.

7. Apredistortion circuit of any one of

claims 1

to

4

, wherein said nonlinear device comprises a diode.

8. Apredistortion circuit of any one of

claims 1

to

4

, wherein said nonlinear device comprises a transistor.

9. A power amplifier comprising:

a predistortion circuit of any one of

claims 1

to

5

; and

an amplifier for amplifying the signal from said predistortion circuit.

10. A power amplifier of

claim 9

, wherein said amplifier comprises:

an input terminal for inputting a signal;

a first matching circuit connected to said input terminal;

a transistor the gate of which is connected to said first matching circuit;

a second matching circuit connected to the drain of said transistor;

an output terminal connected to said second matching circuit and for outputting a signal;

a f irst bias circuit connected between said first matching circuit and said transistor;

a second bias circuit connected between said second matching circuit and said transistor; and

specific-frequency suppressing means connected to one side or both sides of said transistor directly without another intervening device and of suppressing all or part of such frequencies that are from a frequency corresponding to DC to a frequency corresponding to an occupied band width of an input signalinputtedto saidinputterminaland/orsuppressingatleast one higher harmonic frequency of a carrier wave of said input signal.

11. A power amplifier of

claim 10

, wherein said amplifier comprises:

an input terminal for inputting a signal;

a first matching circuit connected to said input terminal;

a transistor the base of which is connected to said first matching circuit;

a second matching circuit connected to the collector of said transistor;

an output terminal connected to said second matching circuit and for outputting a signal;

a first bias circuit connected between said first matching circuit and said transistor;

a second bias circuit connected between said second matching circuit and said transistor; and

specific-frequency suppressing means connected to one side or both sides of said transistor directly without another intervening device and of suppressing all or part of such frequencies that are from a frequency corresponding to DC to a frequency corresponding to an occupied band width of an input signalinputtedtosaidinputterminaland/orsuppressingatleast one higher harmonic frequency of a carrier wave of said input signal.