Title:
VARIABLE GAIN AMPLIFIER
Document Type and Number:
WIPO Patent Application WO/2007/105282
Kind Code:
A1
Abstract:
The gain of an amplifier, e.g. a differential amplifier, is controlled without varying
the input impedance. A variable gain amplifier comprises a plurality of differential
amplifiers connected in parallel, and a plurality of signal switching means
corresponding to the differential amplifiers, respectively, for switching
a positive-phase differential signal and a negative-phase differential signal.
Two outputs from each signal switching means are connected with the positive-phase
input terminal and the negative-phase input terminal of each differential amplifier,
and either the positive-phase differential signal or the negative-phase differential
signal is provided as an input signal.
Inventors:
ARAI TOMOYUKI (JP)
Application Number:
PCT/JP2006/304796
Publication Date:
September 20, 2007
Filing Date:
March 10, 2006
Export Citation:
Assignee:
FUJITSU LTD (JP)
ARAI TOMOYUKI (JP)
ARAI TOMOYUKI (JP)
International Classes:
H03G3/10; H03F3/45; H03F3/68
Foreign References:
| JP2005026760A | 2005-01-27 | |||
| JPH06197035A | 1994-07-15 | |||
| JPH11317635A | 1999-11-16 | |||
| JPS6264109A | 1987-03-23 | |||
| JPH11177357A | 1999-07-02 |
Attorney, Agent or Firm:
OSUGA, Yoshiyuki (Nibancho Bldg. 8-20, Nibancho, Chiyoda-k, Tokyo 84, JP)
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