Variable gain amplifier
First Claim
Patent Images
1. A variable gain amplifier device comprising:
- a variable gain amplifier circuit supplied with an input signal and a feedback signal to amplify a difference between the input signal and the feedback signal to output an output signal;
a feedback circuit which supplies the feedback signal to the variable gain amplifier circuit; and
a controller which controls the variable gain amplifier circuit and the feedback circuit to decrease a cufoff frequency of the feedback circuit with an increase in a gain of the variable gain amplifier circuit or vice versa.
1 Assignment
0 Petitions
Accused Products
Abstract
A variable gain amplifier device comprises a variable gain amplifier circuit which amplifies a difference between an input signal and a feedback signal to output an output signal, a feedback circuit which supplies the feedback signal to the variable gain amplifier circuit, and a controller which controls the variable gain amplifier circuit and the feedback circuit to decrease a cutoff frequency of the feedback circuit according to increase of a gain of the variable gain amplifier circuit or vice versa.
199 Citations
15 Claims
-
1. A variable gain amplifier device comprising:
-
a variable gain amplifier circuit supplied with an input signal and a feedback signal to amplify a difference between the input signal and the feedback signal to output an output signal;
a feedback circuit which supplies the feedback signal to the variable gain amplifier circuit; and
a controller which controls the variable gain amplifier circuit and the feedback circuit to decrease a cufoff frequency of the feedback circuit with an increase in a gain of the variable gain amplifier circuit or vice versa. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
a baseband circuit which converts a radio signal into a baseband signal; and
a variable gain amplifier device according to claim 1 which amplifies the baseband signal.
-
-
10. A variable gain amplifier device comprising:
-
a variable gain amplifier circuit which amplifies a difference between an input signal and a feedback signal to output an output signal;
a feedback circuit which supplies the feedback signal to the variable gain amplifier circuit; and
a controller which controls the gain of the variable gain amplifier circuit and a cutoff frequency of the feedback circuit to make a lower limit frequency of the output signal substantially constant regardless of variation of a gain of the variable gain amplifier circuit. - View Dependent Claims (11, 12)
a baseband circuit which converts a radio signal into a baseband signal; and
a variable gain amplifier device according to claim 10 which amplifies the baseband signal.
-
-
13. A variable gain amplifier device comprising:
-
a variable gain amplifier circuit supplied with an input signal and a feedback signal to amplify a difference between the input signal and the feedback signal and output an output signal, a gain of the variable gain amplifier circuit being varied according to a level of at least one of the output signal and the input signal; and
a feedback circuit which supplies the feedback signal to the variable gain amplifier circuit, a cutoff frequency of the feedback circuit being varied according to variation of the gain of the variable gain amplifier circuit to make a lower limit frequency of the output signal substantially constant. - View Dependent Claims (14, 15)
a baseband circuit which converts a radio signal into a baseband signal; and
a variable gain amplifier device according to claim 13 which amplifies the baseband signal.
-
Specification