Gain Control Amplifier Research Articles

Circuit design of a high scanning frequence and fast response laser methane remote sensor

To solve the problem of slow detection of laser methane sensors based on tunable diode laser absorption spectroscopy (TDLAS), a methane detection system with a high detection rate was proposed. Focusing on the hardware circuit design of the system which consists of a laser driver circuit, laser temperature control circuit, optical amplifier and filter circuit and main control circuit based on FPGA+ARM, this circuit is designed to achieve a laser scanning frequency of 50 kHz. A voltage-controlled current source is designed to drive the laser diode (LD). A TEC controller is designed to keep the operating temperature of the laser diode stable. Since the photocurrent can be very weak, to ensure the quality of signals from the photodiode (PD), a signal collection circuit consisting of the transimpedance amplifier, gain-controlled amplifier and low-pass filter was designed. An experiment is carried out to test system measurement capabilities. The results show the circuit can reach a response time of 2.5 ms while ensuring a measurement error of less than 4.3%.

A Linear-in-Decibel Automatic Gain Control Amplifier With Dual Mode Continuous Gain Tuning

A reconfigurable fully integrated automatic gain control (AGC) amplifier is presented which is based on a dual mode continuous gain adjustment variable-gain amplifier (VGA). The VGA is realized based on the current-steering structure, achieving a linear-in-dB gain tuned by AGC’s feedback voltage. A current division active load is proposed, which provides additional gain control range and realizes gain robustness to process and supply variations without extra calibration. Simulated with Cadence IC, the maximum gain variations due to process and supply variations are 3.5 dB and 2.6 dB, respectively. By using dual mode gain tuning technique, the VGA achieves a total gain range of 68.2 dB. Both bandwidth and gain of the VGA are adjusted independently. The AGC is realized in UMC 55-nm CMOS technology with 0.026 mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> core area. With the current division ratio K of 0.5, the proposed VGA achieves a linear-in-dB gain of 42.2 dB ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$-$</tex-math> </inline-formula> 30.0 to 12.2 dB) with less than 0.79 dB error. The <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$-$</tex-math> </inline-formula> 3 dB bandwidth can be adjusted from 80 MHz to 140 MHz and is insensitive to gain variations. The power dissipation is from 2.9 mW to 4.5 mW. This design features bandwidth scalability and the gain independent of bandwidth to achieve various applications.

A 20-Gb/s wideband AGC amplifier with 26-dB dynamic range in 0.18-μm SiGe BiCMOS

This paper presents a 20-Gb/s automatic gain control (AGC) amplifier in a 0.18-μm SiGe BiCMOS for high-speed applications. The proposed AGC amplifier compactly consists of a folded Gilbert variable-gain amplifier (VGA), a post amplifier (PA), a 50-Ω output buffer, and AGC loop including an open-loop peak detector (PD), a RC low-pass filter (LPF), and an error amplifier (EA). The AGC amplifier achieves the broadband characteristic by utilizing inductive peaking and capacitive degeneration as well as fT-doubler techniques to overcome the large parasitic capacitances. The proposed AGC circuits together with a linear VGA exhibits a wide gain control range of 45 dB for the received signal strength indication (RSSI). The measured AGC amplifier achieves a maximum gain of 21 dB and a -3-dB bandwidth (BW) of 20.6 GHz, which can support up to 25.4-Gb/s data rate. For the pseudorandom bit sequence (PRBS) length 231–1 with a bit-error rate (BER) of 10−12 at 20 Gb/s, the measured input dynamic range is 26 dB (20–400mVpp) and the peak-to-peak data jitter is less than 8 ps. The AGC amplifier consumes a power of 160 mW from a 3.3-V supply voltage and occupies an area of 850 μm × 850 μm.

A remote gain controlled and polarization angle tunable Doppler backward scattering reflectometer.

Remote control of the diagnostic systems is the basic requirement for the high performance plasma operation in a fusion device. This work presents the development of the remote control system for the multichannel Doppler backward scattering (DBS) reflectometers. It includes a remote controlled quasi-optical system and a remote intermediate frequency (IF) amplifier gain control system. The quasi-optical system contains a rotational polarizer, its polarization angle is tunable through a remote controlled motor, and it could combine the microwave beams with a wide frequency range into one focused beam. The remote IF gain control system utilizes the digital microcontroller (MCU) technique to regulate the signal amplitude for each signal channel. The gain parameters of amplifiers are adjustable, and the feedback of working status in the IF system will be sent to MCU in real time for safe operation. The gain parameters could be controlled either by the Ethernet remote way or directly through the local control interface on the system. Preliminary experimental results show the effectiveness of the remote controlled multichannel DBS system.

Design of Programmable Gain Amplifier Module in Dynamic Liquid Level Tester

Oil and gas wells need to perform dynamic liquid level detection during the development to prevent inaccurate detection during drilling and damage the oil and gas field. The Program Controlled Gain Amplifier (PGA) module designed in this paper is used in the dynamic liquid level test instrument. Using STM32F4O7ZGT6 as a microcontroller (MCU), the MCU, a multi-stage variable gain amplifier and a peak detection circuit form a closed loop control, forming an automatic gain control (AGC) circuit. First, the signal output by the peak detection circuit is collected by AD, and then the entire module is in a dynamic balance state through DA feedback. This AGC system can accurately control the gain and output signal. Finally, the ratio-average filtering algorithm is used to test the experimental data. Experimental results show that the module can achieve gain control of-20∼60dB in the frequency range of 1kHz∼20MHz; the relative error of the output voltage is within 3%. This module achieves the performance indicators of broadband, high precision and high gain. Compared with the traditional module, its advantage is that it takes into account and optimizes the three performance indicators at the same time, and has better stability.

직류 오프셋 제거 회로를 가진 저 전력 프로그램 가능한 이득 증폭기 설계

In this paper, a low-power gain control amplifier with a direct current offset cancellation circuit is proposed in order to amplify analog signals. The proposed PGA (Programmable Gain Amplifier) is less sensitive to external influences due to the inclusion of active load on differential amplifiers. The PGA connects a direct current offset cancellation circuit, based on the Miller effect, to a differential amplifier stage to reduce area and compensate for distortion or lack of linearity. This circuit is also designed to be adjustable in eight steps, from 4 dB to 60 dB, using gain controls. The proposed PGA is designed using the TSMC 0.13 μm CMOS process, and was verified by simulation in ADS (Advanced Design System) tool. Compared to conventional research results, the proposed PGA achieved a gain error of less than 0.1 dB and a lower consumption of 0.16 mW.

Design of Audio Signal Analyzer Based on MCU and FPGA

This audio signal analyzer is based on a microcontroller (MCU) and a field programmable gate array (FPGA). It consists of a controllable gain amplifier circuit, an active filter circuit, A / D conversion and D / A feedback circuits, and a main control circuit and liquid crystal display module. Through AD conversion, the audio signal is sampled, the continuous signal is discretized, and then the FFT fast Fourier transform operation is performed to analyze and process each frequency component and power of the audio signal in the time and frequency domain. By controlling the gain of the amplifier to expand the dynamic range of the input signal and improve the sensitivity, it can also complete the corresponding human-computer interaction control based on the PS2 keyboard input, while using the high-resolution LCD to display the signal spectrum. The audio signal frequency range that this system can accurately measure is 20Hz-10KHz, its amplitude range is 5mVpp-5Vpp, and the resolution is divided into 20Hz and 100Hz. The measured power accuracy is as high as 1%, and the period of the periodic signal can be accurately measured, which is the ideal solution for audio signal analyzers.

Performance Analysis of Homodyne-Based FSO System Using Various Optical Amplifiers

AbstractA detailed performance analysis of homodyne-based coherent detection in Free-space optics (FSO) with various optical amplifiers is presented in this paper. Using homodyne detection in FSO system, the effect of scintillation is mitigated. To further enhance the performance of FSO system, various optical amplifiers such as erbium-doped fibre amplifier, semiconductor optical amplifier, gain-controlled amplifier and black box model of amplifier can be employed in the system. Improvement in the system can be validated in terms of BER, Q-factor and eye diagram.

High two-signal dynamic range and accurate frequency measurement for close frequency separation wideband digital receiver using adaptive gain control and adaptive thresholding

In electronic-warfare (EW) receiver applications, real-time measurement of the radar signals' carrier frequencies is mandatory and considered to be one of the most important radar parameters. Accurate frequency detection can be used to sort and deinterleave signals in a dense signal environment where multiple signals arrive simultaneously presenting severe problems unless they can be differentiated appropriately. Researchers and engineers are actively looking for new algorithms for high resolution wideband receivers with easier implementation. This paper presents an adaptive gain control and dynamic thresholding wideband digital receiver to accurately detect two simultaneous high dynamic range signals, even when their signal frequencies are very close. The proposed fast Fourier transform (FFT) based receiver examines incoming signal characteristics and provides real-time accomplishment of these tasks, by way of using an adaptive gain-control amplifier, a squarer, two analog-to-digital converters, and two FFT's. The wideband receiver offers high probability of intercept over wide instantaneous RF bandwidths, high dynamic ranges and sensitivity. Two simultaneous signal accommodations and their characteristics are provided to demonstrate the improvements over presently used receivers in this field.

A Wideband Inductorless dB-Linear Automatic Gain Control Amplifier Using a Single-Branch Negative Exponential Generator for Wireline Applications

This paper reports a wideband inductorless automatic gain control (AGC) amplifier for wireline applications. To realize a dB-linear AGC range, a pseudo-folded Gilbert cell driven by a single-branch negative exponential generator (NEG) is proposed as the core variable-gain amplifier. The NEG features a composite of dual Taylor series to extend the AGC approximation range without sacrificing the precision. Fabricated in 65-nm CMOS, the AGC amplifier occupies a tiny die area of 0.045 mm2 and consumes 28 mW at 1.2 V. Measured over a dB-linear gain range of ~40 dB, < ± 1 dB gain error is achieved and the 3-dB bandwidth stays roughly constant at 7 GHz. For the closed-loop AGC measurement, the input dynamic range is ~40 dB (10 mVpp to 1 Vpp) for a BER <10−12 under a 27 − 1 PRBS data at 10 Gb/s. The achieved figure-of-merit (FOM) of 2.8 pJ/bit compares favorably with state-of-the-art.

디지털 능동형 가변 축전기를 사용한 적응형 이퀄라이저

본 논문은 디지털 능동형 가변 축전기를 사용한 적응형 이퀄라이저를 제안하고 있다. Equalizing amplifier는 주 증폭기와 source degeneration RC 필터로 구성되어 있으며, RC필터를 디지털 능동형 가변 축전기로 구현함으로써 면적 효율을 높이고 선형적인 손실 보상 영역을 확보했다. 능동형 가변 축전기는 miller effect에 의한 임피던스 증가 효과를 사용하였으며, 증폭기 이득 조정을 통해 capacitance의 가변성을 가질 수 있도록 하였다. 시뮬레이션 결과, 능동형 축전기의 선형적 가변 특성을 통해 입력 데이터의 고주파 손실을 보상하여 2Gb/s 전송속도에 대해 0.31 UI의 입력 eye 너비를 0.64 UI로 약 2배 증가시켰다. 적응형 이퀄라이저는 <TEX>$0.13-{\mu}m\;CMOS$</TEX> 공정 값을 사용하여 설계 되었으며, 0.412 mm2 의 레이아웃 면적을 사용한다. This paper proposes an adaptive equalizer with the digitally controlled active variable capacitor. An equalizing amplifier consists of a main amplifier and a source degeneration RC filter which is implemented using the digitally controlled active variable capacitor for area efficiency and linear loss compensation. The active capacitor changes its capacitance by the amplifier gain control, which is based on miller effect. In the simulated results, the proposed equalizer compensates the high frequency loss and extends the data eye width from 0.31 UI to 0.64 UI.

Low-cost bidirectional hybrid fiber-visible laser light communication system based on carrier-less amplitude phase modulation

We propose a bidirectional hybrid fiber-visible laser light communication (fiber-VLC) system. To reduce the cost of the system, the cheap and easy integration red vertical cavity surface emitting lasers, low-complexity carrier-less amplitude phase modulation format, and wavelength reuse technique are utilized. Meanwhile, the automatic gain control amplifier voltage and bias voltage for downlink and uplink are optimized. The simulation results show that, by using the proposed system, the bit error rate of 3.8×10−3 can be achieved for 16-Gbps CAP signal after 30-km standard single mode fiber and 8-m VLC bidirectional transmission. Therefore, it indicates the feasibility and potential of proposed system for indoor access network.

A CMOS low power fast-settling AGC amplifier based on integrated RSSI

This paper presents a low power CMOS feedforward automatic gain control (AGC) amplifier based on an integrated received signal strength indicator (RSSI) with process-variation tolerance. Low ripple high dynamic RSSI and fast settling AGC are both achieved with a power-efficient implementation. Raised feedforward AGC amplifier also gets superior linearity to cascade ones due to its high dynamic range detection to input signals. No external component is needed and this design was fabricated in 0.18 μm CMOS process. The measurement results show that RSSI gains at least 60-dB log-linear range and the AGC convergence time is less than 7.8-μs for a 2 MHz signal. It draws 1.1 mA from a 1.5 V supply and obtains ?52-dB THD with 0.7 Vpp output voltage.

The Design Of The Ultrasonic Nondestructive Testing System Based On The EMAT

This paper introduces a kind of based on the electromagnetic acoustic transducer (EMAT) metal pipeline detection system, fusion of two dimensional orientation, shape unique technological innovation, implementation of various metal pipe wall corrosion situation of rapid, accurate, fully automated non-destructive testing.In the aspect of hardware design, single-chip microcomputer control was achieved by C language programming the launch of the pulse signal. Pulse signal was sent to launch circuit, ultrasonic signal. Design of preamplifier, controllable gain amplifier two-stage amplifier circuit for receiving signal is amplified. Including data acquisition circuit detection circuit and A/D conversion circuit, single chip microcomputer and the LabVIEW platform via A serial port communication agreement. In the aspect of software design, the design of the EMAT pipe nondestructive testing system based on LabVIEW human-computer interaction interface.

Excursion-Free Dynamic Wavelength Switching in Amplified Optical Networks

Dynamic optical networking with rapid wavelength reconfiguration is a promising capability to support the heterogeneous, bursty traffic rapidly growing in metro-area networks. A major obstacle to realizing dynamicity in the optical layer is the channel power excursions that occur due to continuously changing input conditions into gain controlled optical amplifiers. Here we present a technique of distributing an optical signal across multiple wavelengths chosen to reduce or cancel the power dynamics so that excursion-free switching can be achieved in an optically amplified transparent network. The use of variable wavelength dwell times for excursion-free switching using arbitrary wavelength pairs is presented. Spectral efficiency lost in utilizing multiple wavelengths is recovered through time-division multiplexing two signals distributed over the same wavelengths.

A 2.2 mW, 40 dB Automatic Gain Controllable Low Noise Amplifier for FM Receiver

This paper presents an automatic gain controllable low noise amplifier (AGC-LNA) for FM receiver (FMRx). The proposed LNA adopts current reused dual g <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">m</sub> -boosting technique for the power saving. And, a simple analog type automatic gain control (AGC) loop is proposed that provides high resolution gain control. Implemented in a 65 nm CMOS technology, measurements show power regulation range of 40 dB with ±1 dB error, less than -11 dB of S11, variable voltage gain range of -12 to 30 dB over the frequency range of 88 ~ 108 MHz, noise figure (NF) of less than 2.9 dB, P1dB of higher than -24.2 dBm, and IIP3 of higher than -12.7 dBm in the high gain (HG) mode, while dissipating only 1.8 mA from a 1.2 V supply, respectively.

Automotive Anti-Collision Radar Signal Processing System Design Based on DSP

The principle of the frequency modulated continuous wave radar for measuring distance and velocity and signal processing method are described in this paper; To solve the signal processing problem for FMCW automotive anti-collision radar system ,the radar signal processing circuit is researched and designed, including the design of corresponding gain control amplifier circuit, power supply and filter circuit, external memory circuit ,power supply circuit ,signal interface circuit, and analyzed the results of the measurement for system. Experiments showed that the system achieved good accuracy design effect and higher measurement precision and has certain positive role to improve vehicle safety.

A Zero-Pole Reposition Based, 0.95-mW, 68-dB, Linear-in-dB, Constant-Bandwidth Variable Gain Amplifier

A variable-gain amplifier with very low power consumption and wide tuning range is presented. The operational principle of this unique structure is discussed, its most important formulas are derived and its outstanding performance is verified by simulation in TSMC 0.18-μm N-well CMOS fabrication process. Owing to the novel zero-pole repositioning technique, the proposed circuit demonstrates very high frequency bandwidth of 79 MHz while drawing only 0.52 mA from 1.8 V power supply. The interesting results such as a very small core area of about 0.0025 mm2 as well as a wide linear-in-dB and constant-bandwidth tuning range of 68.2 dB along with a very low power consumption of 0.95 mW are achieved utilizing standard CMOS technology. The stability of the proposed VGA is verified through transient sinusoidal response analysis. Full process, voltage and temperature (PVT) variation analysis of the circuit is also investigated through Monte Carlo and corner case analysis in order to approve the robustness of the structure. Monte Carlo simulations show standard deviation values of 4.6 dB and 78.3 MHz in gain and gain-bandwidth product, respectively. These results show that our zero-pole repositioning method would lend itself well for use in low-power and high-frequency applications, especially in high-speed automatic gain control amplifiers.

DC feedback for wide band frequency fixed current source

Abstract Alternating current sources are mainly used in bioelectrical impedance devices. Nowadays 50 – 100 kHz bioelectrical impedance devices are commonly used for body composition analysis. High frequency bioelectrical impedance analysis devices are mostly used in bioimpedance tomography and blood analysis. High speed op-amps and voltage comparators are used in this circuit. Direct current feedback is used to prevent delay. An N-Channel J-FET transistor was used to establish the voltage controlled gain amplifier (VCG). A sine wave signal has been applied as input voltage. The value of this signal should be constant in 170 mV rms to keep the output current in about 1 mA rms. Four frequencies; 100 kHz, 1 MHz, 2 MHz and 3.2 MHz were applied to the circuit and the current was measured for different load resistances. The results showed that the current was stable for changes in the resistor load, bouncing around an average point as a result of bouncing DC feedback.

A 5-Gb/s Automatic Gain Control Amplifier With Temperature Compensation

This paper presents an automatic gain control (AGC) amplifier with temperature compensation for high-speed applications. The proposed AGC consists of a folded Gilbert variable gain amplifier (VGA), a dc offset canceller, inductorless post amplifiers, a linear open-loop peak detector (PD), an integrator, a symmetrical exponential voltage generator, and a compensation block for temperature stability. The novel temperature compensation scheme ensures the AGC stability and accuracy over <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex Notation="TeX">${-}$</tex></formula> 20 <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex Notation="TeX">$\,^{\circ}$</tex></formula> C–200 <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex Notation="TeX">$\,^{\circ}$</tex></formula> C by predicting the integrator biasing voltage based on the crucial blocks duplication technique. The proposed linear open loop PD combined with the linear-in-dB VGA manages the dB-linear error of less than 0.3 dB for the received signal strength indication (RSSI). The AGC chip is fabricated using a 0.13- <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex Notation="TeX">$\mu$</tex></formula> m SiGe BiCMOS technology. Consuming a power of 72 <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex Notation="TeX">$~$</tex> </formula> mW from a 1.2-V supply voltage, the fabricated circuit exhibits a voltage gain of 40 dB and a 3-dB bandwidth of 7.5 GHz. With a 2 <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex Notation="TeX">$^{15}-$</tex></formula> 1 pseudo-random bit sequence at 5-Gb/s, the measured peak-to-peak jitter is less than 40 <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex Notation="TeX">${\hbox {ps}}_{\rm pp}$</tex></formula> across the <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex Notation="TeX">${-}$</tex></formula> 20 <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex Notation="TeX">$\,^{\circ}$</tex></formula> C–200 <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex Notation="TeX">$\,^{\circ}$</tex></formula> C temperature range. The low linear-in-dB error and the wide operating temperature range achieving the high-speed data input signal indicate the suitability of the proposed techniques for high-speed AGC amplifiers.