Title:
LOW NOISE AMPLIFIER
Document Type and Number:
WIPO Patent Application WO/2007/105277
Kind Code:
A1
Abstract:
In a first transistor, the source is connected to the input terminal and the drain
is connected to the output terminal. A first variable impedance circuit is arranged
between the gate of the first transistor and ground and the impedance is changed
according to a first control signal. A second variable impedance circuit is arranged
between the gate and the source of the first transistor and the impedance is changed
according to a second control signal. The ratio of the impedance of the first and
the second variable impedance circuits can be set to an arbitrary value according
to the first and the second control signals to change the gain of a low-noise amplifier.
In other words, the low-noise amplifier whose gain can be changed can be configured
without arranging an element causing to increase noise in a signal path from the
input terminal to the output terminal. Thus, the occurrence of unnecessary thermal
noise can be suppressed to improve the noise characteristics of the low-noise
amplifier.
Inventors:
SATOH HIROYUKI (JP)
YAMAZAKI HIROSHI (JP)
YAMAZAKI HIROSHI (JP)
Application Number:
PCT/JP2006/304772
Publication Date:
September 20, 2007
Filing Date:
March 10, 2006
Export Citation:
Assignee:
FUJITSU LTD (JP)
SATOH HIROYUKI (JP)
YAMAZAKI HIROSHI (JP)
SATOH HIROYUKI (JP)
YAMAZAKI HIROSHI (JP)
International Classes:
H03G3/10; H03F1/26
Foreign References:
| JPS5262053U | 1977-05-07 | |||
| JPS49107941U | 1974-09-14 | |||
| JPS5494858A | 1979-07-26 |
Attorney, Agent or Firm:
FURUYA, Fumio et al. (19-5 Nishishinjuku 1-chome, Shinjuku-k, Tokyo 23, JP)
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