VARIABLE GAIN TYPE DIFFERENTIAL AMPLIFYING CIRCUIT, AND MULTIPLYING CIRCUIT

Title:

VARIABLE GAIN TYPE DIFFERENTIAL AMPLIFYING CIRCUIT, AND MULTIPLYING CIRCUIT

Document Type and Number:

Japanese Patent JP2003168937

Kind Code:

A

Abstract:

To provide a variable gain type differential amplifier which can materialize distortion on and under a certain level, and a multiplying circuit using it.

The emitter of a transistor 1 is connected to a node N11, a resistor 51 is connected between the node N11 and a node N12, and a resistor 52 is connected between the node N12 and a grounding terminal. The emitter of a transistor 2 is connected to a node N21, a resistor 61 is connected between the node N21 and a node N22, and a resistor 62 is connected between the node N22 and a grounding terminal. An FET 71 is connected between the nodes N11 and N21, and an FET 72 is connected between the nodes N12 and N22. The gates of the FETs 71 and 72 are connected to a control terminal NG, which receives control voltage AGC via resistors 81 and 82, respectively. The resistors 51, 52, 61, and 62, and FETs 71 and 72 constitute a variable resistance circuit 30.

Inventors:

BABA SEIICHI

Application Number:

JP2001363753A

Publication Date:

June 13, 2003

Filing Date:

November 29, 2001

Export Citation:

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Assignee:

SANYO ELECTRIC CO

International Classes:

G06G7/16; H03D7/14; H03F1/32; H03F3/45; H03G3/10; (IPC1-7): H03G3/10; G06G7/16; H03D7/14; H03F1/32; H03F3/45

Attorney, Agent or Firm:

Fukushima Shoto

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