US 11,942,913 B2
Variable gain amplifier
Hiroshi Hamada, Tokyo (JP); and Hideyuki Nosaka, Tokyo (JP)
Assigned to Nippon Telegraph and Telephone Corporation, Tokyo (JP)
Appl. No. 16/978,541
Filed by Nippon Telegraph and Telephone Corporation, Tokyo (JP)
PCT Filed Feb. 27, 2019, PCT No. PCT/JP2019/007512
§ 371(c)(1), (2) Date Sep. 4, 2020,
PCT Pub. No. WO2019/187924, PCT Pub. Date Oct. 3, 2019.
Claims priority of application No. 2018-067532 (JP), filed on Mar. 30, 2018.
Prior Publication US 2021/0021248 A1, Jan. 21, 2021
Int. Cl. H03F 3/24 (2006.01); H01P 5/18 (2006.01); H03D 1/10 (2006.01); H03G 3/30 (2006.01); H04B 1/04 (2006.01)
CPC H03G 3/3042 (2013.01) [H01P 5/18 (2013.01); H03D 1/10 (2013.01); H03F 3/24 (2013.01); H04B 1/04 (2013.01)] 19 Claims
OG exemplary drawing
 
1. A variable gain amplifier, comprising:
a gain adjuster comprising a switch having a control terminal in an input of an amplifier circuit; and
a power monitor branched in an output of the amplifier circuit, wherein the power monitor comprises:
a coupler, a first end of the coupler being connected to an output line of the amplifier circuit;
a diode, an anode of the diode being connected to a second end of the coupler; and
a monitor terminal connected to a cathode of the diode via a low-pass filter, the anode of the diode being set to ground potential.