Variable gain amplifier

Patent metadata

Field	Value
Publication number	US-11942913-B2
Application number	US-201916978541-A
Country	US
Kind code	B2
Filing date	Feb 27, 2019
Priority date	Mar 30, 2018
Publication date	Mar 26, 2024
Grant date	Mar 26, 2024

Abstract

A gain adjustment unit constituted by a distribution switch having a control terminal is provided in an input unit of an amplifier circuit. One end of a coupler is connected to an output line of the amplifier circuit, another end of the coupler is connected to an anode of a diode, and a monitor terminal is connected via a low-pass filter to a cathode of the diode. The anode of the diode is unbiased.

First claim

The invention claimed is:

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.

2. The variable gain amplifier according to claim 1 , wherein the switch is a distribution switch.

3. The variable gain amplifier according to claim 1 , wherein the coupler is a resistive element.

4. The variable gain amplifier according to claim 1 , further comprising a transmission line or an inductor, wherein a first end of the transmission line or the inductor is connected to ground potential as a short stub, and wherein a second end of the transmission line or the inductor is connected to the anode of the diode.

5. The variable gain amplifier according to claim 4 , wherein an impedance value of the short stub is set so as to configure a parallel resonance circuit with an input capacitance of the diode at an operating frequency.

6. The variable gain amplifier according to claim 1 , wherein the coupler is a grounded waveguide coupler.

7. The variable gain amplifier according to claim 1 , wherein a value of a voltage generated at the anode of the diode exceeds 0.7 V.

8. The variable gain amplifier according to claim 1 , wherein a value of a voltage generated at the anode of the diode exceeds 0.5 V.

9. The variable gain amplifier according to claim 1 , wherein a value of a voltage generated at the anode of the diode exceeds 0.25 V.

10. A method comprising:
connecting a power monitor in an output of an amplifier circuit;
wherein a gain adjuster comprises a switch having a control terminal in an input of the amplifier circuit; and
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; and

wherein the method further comprises setting the anode of the diode to ground potential.

11. The method of claim 10 , wherein the power monitor is branched in the output of the amplifier circuit.

12. The method of claim 10 , wherein the switch is a distribution switch.

13. The method of claim 10 , wherein the coupler is a resistive element.

14. The method of claim 10 , wherein setting the anode of the diode to ground potential comprises:
connecting a first end of a transmission line or a inductor to ground potential as a short stub; and
connecting a second end of the transmission line or the inductor to the anode of the diode.

15. The method of claim 14 , wherein an impedance value of the short stub is set so as to configure a parallel resonance circuit with an input capacitance of the diode at an operating frequency.

16. The method of claim 10 , wherein the coupler is a grounded waveguide coupler.

17. The method of claim 10 , wherein a value of a voltage generated at the anode of the diode exceeds 0.7 V.

18. The method of claim 10 , wherein a value of a voltage generated at the anode of the diode exceeds 0.5 V.

19. The method of claim 10 , wherein a value of a voltage generated at the anode of the diode exceeds 0.25 V.

Assignees

• Nippon Telegraph & Telephone

Inventors

• Hamada Hiroshi
• Nosaka Hideyuki

Classifications

• H03G3/3042 Primary

  in modulators, frequency-changers, transmitters or power amplifiers · CPC title

• H01P5/18

  consisting of two coupled guides, e.g. directional couplers · CPC title

• H03D1/10

  of diodes · CPC title

• H03F3/24

  of transmitter output stages · CPC title

• H04B1/04

  Circuits · CPC title