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Automatic gain control circuit

A technology of automatic gain control and gain circuit, which is applied in the direction of gain control, amplification control, and control of components of the amplification device, etc., and can solve problems such as the temperature change of the output amplitude value of the variable gain circuit 3

Inactive Publication Date: 2015-07-01
NIPPON TELEGRAPH & TELEPHONE CORP +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

when Figure 4 When the temperature dependence of the output voltage THo of the peak detection circuit 50 and the average voltage Ave of the average value detection circuit 51 are different, the phenomenon that the output amplitude value of the variable gain circuit 3 changes with temperature may occur

Method used

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  • Automatic gain control circuit
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  • Automatic gain control circuit

Examples

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Effect test

no. 1 example

[0025] as Figure 4 As shown in the conventional automatic gain control circuit 5, the figure 1 The illustrated automatic gain control circuit 5a generates a gain control signal, and outputs the gain control signal to the variable gain circuit 3 that amplifies the main signal, so as to set the output amplitude by the automatic gain control circuit 3 while monitoring the output amplitude of the variable gain circuit 3. The amplitude set by the gain control circuit 5a.

[0026] The automatic gain control circuit 5a includes a peak detection circuit 10, an average value detection and output amplitude setting circuit (hereinafter referred to as "average detection / output amplitude setting circuit") 11, and a high-gain amplifier 12 serving as a differential amplification circuit.

[0027] Such as Figure 4Like the conventional peak detection circuit 50 shown, the peak detection circuit 10 is a circuit that detects and outputs the peak voltage of the output signal from the variable ...

no. 2 example

[0052] as shown in the picture Figure 4 shown in the conventional automatic gain control circuit 5 and figure 1 shown in automatic gain control circuit 5a, figure 2 The illustrated automatic gain control circuit 5b generates and outputs a gain control signal to the variable gain circuit 3 to set the output amplitude to the amplitude set by the automatic gain control circuit 5b while monitoring the output amplitude of the variable gain circuit 3 .

[0053] The automatic gain control circuit 5 b includes a peak detection circuit 10 , an average value detection / output amplitude setting circuit 11 , a high-gain amplifier 12 and a buffer circuit 13 . automatic gain control circuit 5b with figure 1 The automatic gain control circuit 5a shown is different in that a buffer circuit 13 is inserted into the non-inverting input port IT and the inverting input port IC and the input ports 10i1 and 10i2 of the peak detection circuit 10, the average value detection / output amplitude setti...

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Abstract

In an automatic gain control circuit, a peak detection circuit detects and outputs the peak voltage of an output signal from a variable gain circuit. An average value detection / output amplitude setting circuit detects the average value voltage of an output signal from the variable gain circuit, and outputs a voltage obtained by adding a voltage with an amplitude 1 / 2 a desired output amplitude of the variable gain circuit to the average value voltage. An amplification circuit controls the gain of the variable gain circuit by amplifying the difference between the output voltages of the peak detection circuit and average value detection / output amplitude setting circuit and outputting a gain control signal to the variable gain circuit. The number of base-emitter junctions of transistors on a path in the peak detection circuit from input ports which receive output signals from the variable gain circuit to an output port which outputs a voltage to the amplification circuit is equal to the number of base-emitter junctions of transistors on a path in the average value detection / output amplitude setting circuit from input ports which receive output signals from the variable gain circuit to an output port which outputs a voltage to the amplification circuit.

Description

technical field [0001] The present invention relates to an automatic gain control circuit which automatically controls the gain of a variable gain circuit in a semiconductor integrated circuit. Background technique [0002] Conventionally, an automatic gain control circuit has been used as a constituent element of a transimpedance amplifying circuit that simultaneously converts minute photocurrent into a voltage signal and amplifies it. Figure 4 It shows the spanning method disclosed in Non-Patent Document 1 (Kimikazu Sano et al. "A Wideband Low-distorted ROSA for Video Distribution Service based on FM Conversion Scheme", ECOC 2007 Proceedings, Vol.3, pp.167-168, 2007). The structure of the resistance amplifier circuit. [0003] The transimpedance core circuit 1 converts a current signal obtained by a light receiving element such as a photodiode (not shown) into a voltage signal. The offset compensation circuit 2 compensates the offset of the output signal from the transim...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H03G3/20
CPCH03G1/0023
Inventor 佐野公一福山裕之野坂秀之中村诚村田浩一十林正俊井锅泰宣土屋英祐
Owner NIPPON TELEGRAPH & TELEPHONE CORP