Title:
VARIABLE GAIN AMPLIFIER AND VARIABLE CURRENT DIVISION CIRCUIT
Document Type and Number:
Japanese Patent JP3455063
Kind Code:
B2
Abstract:
PROBLEM TO BE SOLVED: To provide a variable gain amplifier whose gain is switched with high accuracy by digital control.
SOLUTION: An input signal from an input terminal 1 is given to an input stage circuit 2, where the signal is subject to voltage-current conversion, a signal current is given to a variable current division circuit 3, a signal current outputted from the variable current division circuit 3 is subject to current voltage conversion by an output stage circuit 4, an output signal is extracted at an output terminal 6 and a current division ratio selection circuit 5 is used to select a current division ratio of the variable current division circuit 3 to select a gain in the variable gain amplifier. An input impedance Zi3 of the variable current division circuit 3 is selected smaller than an output impedance ZO2 of the input stage circuit 2, and an output impedance ZO3 of the variable current division circuit 3 is selected higher than an input impedance Zi4 of the output stage circuit 4.
Inventors:
Osamu Watanabe
Takafumi Yamaji
Takafumi Yamaji
Application Number:
JP14960697A
Publication Date:
October 06, 2003
Filing Date:
June 06, 1997
Export Citation:
Assignee:
Toshiba Corporation
International Classes:
H03G3/10; (IPC1-7): H03G3/10
Domestic Patent References:
| JP62132412A | ||||
| JP6097712A | ||||
| JP57196609A | ||||
| JP8111614A | ||||
| JP49132958A |
Attorney, Agent or Firm:
Takehiko Suzue (6 outside)