Title:
PREDISTORTION TYPE LINEARIZER AND ITS ALARM DETECTING METHOD
Document Type and Number:
Japanese Patent JP3726038
Kind Code:
B2
Abstract:
PROBLEM TO BE SOLVED: To provide a predistortion type linearizer which can detect an alarm easily when abnormality is generated in a negative feedback loop.
SOLUTION: In the predistortion type linearizer which performs nonlinear distortion compensation of a power amplifier by a negative feedback system, power calculators 17 and 18 calculate and output power of a feedback base band signal and power of a transmission base band signal, respectively. Power comparator 19 compares output power of the calculators 17, 18 with each other and obtains a distortion compensation coefficient. A differentiation circuit 21 obtains change in time from a distortion compensation coefficient of the power comparator 19 output and an immediately preceding distortion compensation coefficient. When an abnormal state of the negative feedback loop which exceeds a previously determined convergence time is detected, the differentiation circuit outputs an alarm signal. An alarm detecting circuit 22 controls output power of a power amplifier 9 in accordance with the alarm signal.
Inventors:
Kiyota Naoai
Application Number:
JP2001190178A
Publication Date:
December 14, 2005
Filing Date:
June 22, 2001
Export Citation:
Assignee:
NEC Mobile Co., Ltd.
International Classes:
H03F1/32; H03F1/34; H04B1/04; H04L27/20; H04L27/36; (IPC1-7): H03F1/32; H03F1/34; H04B1/04; H04L27/20; H04L27/36
Domestic Patent References:
| JP2002232305A | ||||
| JP10178357A | ||||
| JP200069098A | ||||
| JP11284675A |
Attorney, Agent or Firm:
Masahiko Desk
Masashi Kudo
Yasuhisa Tanizawa
Masashi Kudo
Yasuhisa Tanizawa
Previous Patent: ARTICLE DELIVERY SYSTEM
Next Patent: METHOD OF MANUFACTURING INSIDE SURFACE COATED VESSEL AND INSIDE SURFACE COATED VESSEL
Next Patent: METHOD OF MANUFACTURING INSIDE SURFACE COATED VESSEL AND INSIDE SURFACE COATED VESSEL