Variable gain amplifier circuit and gain control method thereof
First Claim
1. A variable gain amplifier circuit comprising:
- a plurality of variable gain circuits;
a plurality of level detector circuits which detect signal levels at respective inputs of said plurality of variable gain circuits; and
a plurality of gain control circuits which separately control respective gains of said plurality of variable gain circuits, wherein each of said plurality of gain control circuits determines a gain to be set therein, based on the signal level detected by one which is connected thereto of said plurality of level detector circuits and information about gain control received from a part or all of other gain control circuits existing in its preceding stage or stages.
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Accused Products
Abstract
In order to rapidly control the gains of a plurality of variable gain amplifiers VGAs, each of gain control circuits is configured to determine a gain to be set therein, based on gain control information received from other gain control circuits existing in its preceding stage or stages and the signal level detected by a level detector circuit connected thereto. By carrying out such gain control, a total application gain is stabilized more quickly by gain control. Therefore, even in receiving systems that the preparation period for reception is very short, desired gain control is achieved within this period and stable data reception can be performed.
31 Citations
11 Claims
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1. A variable gain amplifier circuit comprising:
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a plurality of variable gain circuits;
a plurality of level detector circuits which detect signal levels at respective inputs of said plurality of variable gain circuits; and
a plurality of gain control circuits which separately control respective gains of said plurality of variable gain circuits, wherein each of said plurality of gain control circuits determines a gain to be set therein, based on the signal level detected by one which is connected thereto of said plurality of level detector circuits and information about gain control received from a part or all of other gain control circuits existing in its preceding stage or stages. - View Dependent Claims (2, 3, 4)
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5. A receiver circuit comprising:
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a variable gain low-noise amplifier which amplifies received high frequency signals;
a mixer which converts a signal output from said variable gain low-noise amplifier into an intermediate frequency signal;
a variable gain circuit which amplifies a signal output from the mixer;
a first level detector circuit which detects the signal level of said variable gain low-noise amplifier;
a first gain control circuit which controls the gain of said variable gain low-noise amplifier;
a second level detector circuit which detects the signal level of said variable gain circuit; and
a second gain control circuit which controls the gain of said variable gain circuit, wherein said first gain control circuit controls the gain of said variable gain low-noise amplifier, based on the signal level detected by said first level detector circuit, and supplies information about the gain control to said second gain control circuit, and wherein said second gain control circuit controls the gain of said variable gain circuit, based on the signal level detected by said second level detector circuit and said information about the gain control. - View Dependent Claims (6, 7, 8, 9, 10)
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11. and 12. (Cancel)
Specification