Transmission power amplifier unit

• US 20020086709A1
• Filed: 01/29/2002
• Published: 07/04/2002
• Est. Priority Date: 09/30/1999
• Status: Active Grant

• Current Assignee: Fujitsu Limited
• Original Assignee: Fujitsu Limited
• Inventors: Saito, Yutaka, Matsuda, Ayanori
• Granted Patent: US 7,058,370 B2
• Time in Patent Office: Days
• US Class Current: 455/561
• CPC Class Codes: H03F 1/32 Modifications of amplifiers to reduce non-linear distortion by negative feedback H03F1/34
• CPC Class Codes: H03F 1/3229 using a loop for error extraction and another loop for error subtraction
• 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
• CPC Class Codes: H03F 2200/105 A non-specified detector of the power of a signal 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
• CPC Class Codes: H03G 3/3042 in modulators, frequency-changers, transmitters or power amplifiers transmission power control in bidirectional transmission systems H04W52/04
• CPC Class Codes: H04B 1/04 Circuits
• CPC Class Codes: H04W 52/52 using AGC [Automatic Gain Control] circuits or amplifiers

Abstract

A transmission power amplifier unit of a base-station apparatus for compensating for non-linear distortion of a transmission power amplifier by feed-forward control is provided with a gain varying unit for varying gain of the transmission power amplifier unit. At start-up of the transmission power amplifier unit, a controller determines whether the base-station apparatus is in a blossoming mode or breathing mode, maximizes gain of the transmission power amplifier unit by controlling the gain varying unit if the mode is the blossoming mode and increases the gain gradually in proportion to the passage of time if the mode is the breathing mode.

Claims

1. A transmission power amplifier unit, which has a transmission power amplifier and provided in a base-station apparatus, for compensating for non-linear distortion of the transmission power amplifier by feed-forward control, comprising:

a gain varying unit for varying gain of the transmission power amplifier unit; and

a controller which, at start-up of the transmission power amplifier unit, is for determining whether the base-station apparatus is in a blossoming mode or breathing mode, maximizing gain of the transmission power amplifier unit if the mode is the blossoming mode and increasing the gain of the transmission power amplifier unit gradually if the mode is the breathing mode.

2. A transmission power amplifier unit according to claim 1, wherein said gain varying unit is an attenuator the attenuation of which is variable, and said controller increases the gain of the transmission power amplifier unit gradually by gradually decreasing the attenuation of said attenuator.

3. A transmission power amplifier unit according to claim 1, wherein said controller includes:

a detection circuit provided in an input section of the transmission power amplifier unit for detecting input power; and

means for discriminating mode based upon whether said input power is equal to or greater than a threshold level.

4. A transmission power amplifier unit according to claim 1, wherein said controller includes:

a detection circuit provided in an output section of the transmission power amplifier unit for detecting output power; and

means for discriminating mode based upon said output power value.

5. A transmission power amplifier unit according to claim 1, wherein said controller confirms a mode on the condition that the same mode is discriminated a plurality of times in succession.

6. A transmission power amplifier unit according to according to claim 3, wherein a predetermined level within a range in which input power varies in the blossoming mode is adopted as said threshold level.

7. A transmission power amplifier unit according to claim 1, further comprising:

a memory for storing correspondence between time from start of control in the blossoming mode and an ideal output value of the transmission power amplifier unit;

a detector circuit for output power of the transmission power amplifier unit; and

a timer for monitoring time from start of blossoming control;

said controller controls said gain varying unit in such a manner that the difference between an ideal value and a detected value at the present time becomes zero.