Electrical Engineering Stack Exchange
Electrical Engineering Stack Exchange

Questions tagged [automatic-gain-control]

For questions about automatic gain control (AGC) circuits.

For questions about automatic gain control (AGC) circuits.

See Wikipedia's article on automatic gain control for more information.

17 questions
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Design of an Automatic Gain Control Using a JFET

simulate this circuit – Schematic created using CircuitLab I have implemented the above circuit which is supposed to amplify a negative 200kHz sinusoid to constant amplitude even if the amplitude is varied. The constant amplitude is adjusted…
Simon Sultana
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Converting AGC Schematic from Single Sided to Dual Sided Supply

I am working with the attached circuit, sourced from here: Original This circuit is designed for a single sided power supply and has worked very well for me in the past. For a new project, I would like to use it with a dual sided power supply,…
Telluride
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RC oscillator loop stability with AGC

I am trying to design a sine wave oscillator. The frequency is about 10 kHz (not critical), the distortion should be reasonable but not necessarily super good (say under 1%). However, the amplitude has to be stable, well defined and repeatable for…
Hyp
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Design of a band-pass filter with automatic gain control using a JFET

I have implemented this circuit which is supposed to do AGC and filter out the signal between 20 Hz-20 kHz, but it seems have some problems. The bandpass filter works well, but the agc circuit doesn't have a different gain for different input…
Jeremy Wang
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AGC circuit for a spectrum analyzer - seeking recomendations

I want to build a spectrum analyzer for my car stereo. 5 bands, left & right channels represented individually, 20 LEDS per band using cascading LM3915s per band and channel. (Yes, 20 LM3915s, 200 LEDs in total, I'll be busy for a MONTH…
Super-Dave
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How does AGC work in this circuit?

I've got this audio amplifier board, which contains exactly the following circuit: I'm trying to understand this circuit, and the "AGC Control" part (highlighted in blue) has me the most curious. What I had assumed is that AGC means "Automatic Gain…
Christopher H.
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Automatic gain controller gain action

Can you guys explain to me how the turning on of Q2 and the charging of C2 increases the vgs of the FET? An equation would be helpful.
Paumdrdo
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Audio volume levelling / AGC for spectrum analyser

I'm busy building a preamp, and want to include an LED-matrix spectrum analyser on the front panel (for aesthetics, not accuracy!) I've set up a circuit that uses a couple of MSGEQ7 chips to analyse both channels of an input audio signal, feeding an…
abza
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Design an AGC circuit for microphone using JFET

At the beginning of the circuit, I designed a 20Hz to 20kHz second-order Butterworth bandpass filter circuit, and then I tried to pass the filtered signal through an AGC circuit to achieve a smooth output. I tried frequency domain simulations with…
Jeremy Wang
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What resistor value could I use to replace this S-Meter?

I'm designing a 40m radio. The schematic I'm using as reference uses a galvanometer ("S") for measuring the signal level. I'm trying to replace it with a sense resistor and an LM358 to read with an Arduino but I'm not sure what value resistor is…
Arheisel
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Why is my voltage pulsing when using a DAC as an input to an OTA?

I'm using the LM13700 in an automatic gain control configuration to adjust the volume of a speaker based on the audio level perceived by the microphone. Both amplifiers on the chip are used: one to handle the incoming microphone signal, and the…
meekeech
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Automatic Gain Compensation of Difference Amplifier

I want to know about the possible solutions to achieve precise automatic gain correction of the difference amplifier ? Description: I am using a differential amplifier and all resistors have 1% tolerance according to specs. After some time the gain…
Khalil
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Questions to a VGA

I found this VGA from texas instruments. On page 34 you can see a AGC (automatic gain control) loop, does this set the output voltage (Vout) to the Vref voltage? The VCA821 needs a bipolar supply voltage, I wanted to use this switched capacitor…
electrococuk
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How can Gilbert Cell circuit provide linear gain variation even though ID-gm relationship is nonlinear?

How can Gilbert Cell circuit provide linear gain variation even though ID-gm relationship is nonlinear? As I undertstand it, the vcontrol (the voltage at the gate of M5 and M6) changes the biasing current of M5 and M6. This current are then copied…
Codelearner777
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AGC (automatic gain control) circuit for brushless phase measurement?

Intro: I am projecting a Brushless motor driver which relevant specs here are basically: use with 6v to 60v. To make it work the circuit's microcontroller needs to analyze the signal that comes from the motor phases through ADC - which can not…
Emanuel M
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