Narrow-band Amplifier Research Articles

Об опыте разработки мобильного комплекса для регистрации электрической активности головного мозга на базе технологии сухих электродов

The technology of creating a mobile complex for registration of the brain electrical activity, for recording an electroencephalographic signal with one channel, is considered. Previously, technological problems associated with insufficient sensitivity and selectivity in the sense of signal-to-noise ratio did not allow the use of electroencephalographic activity recording systems based on the so-called dry electrodes in practical applications. At the same time, even with a small number of leads, such signals, when recorded, for example, from the visual cortex localized in the occipital region of the brain can be extremely informative in the context of the operator activity analysis and other types of human activity, in which arbitrary control of attention plays an essential role. This paper considers the experience of creating a mobile autonomous complex for recording such signals for the tasks of monitoring the characteristics of the operator's activities in scientific applications. The design features of such a device, created based on Node MCU technology, which is gaining wide distribution in embedded systems, proprietary narrowband amplifiers of the electric signal and dry electrodes created by industry in the last decade, are described. Some examples of practical application of such a complex are given. The most promising directions for the development of technology are discussed.

High-performance class-E power amplifier integrated with a microstrip bandpass-filter for wireless applications

In this paper, a class-E power amplifier using a harmonic control network consisting of a bandpass filter and a harmonic control circuit is presented. The advantage of using the bandpass filter in the harmonic control network is the elimination of the DC-block capacitor between the transistor and the load. As a result, losses due to this capacitor are eliminated at operating frequencies. In this design, a new narrow bandpass filter is used with a practical central frequency of 2.4 GHz. The filter carries the maximum power to the load due to its low insertion loss. On the other hand, the harmonic control circuit comprises a tunable elliptic resonator, which resonated in the third harmonic and a quadratic wavelength line, which controls the even harmonics. The input impedance of the harmonic controller circuit is also controlled by a microstrip transmission line that minimizes the parasitic effects of the transistor output. This design is fabricated and measured on the RO4001 board. The maximum measured power output of this narrow-band amplifier is 24 dBm, with 72% power added efficiency.

Monte Carlo analysis of inductor-less wideband amplifier

As more and more applications are being integrated on single chip, the focus of research is being shifted to low cost and better performance wide band amplifiers than the narrow band amplifiers which were suitable for devices having single application. Mostly the wide band amplifiers are designed using inductors so as to overcome the effect of capacitive parasitic but it leads to overshoot and thus resulting in bad frequency response. So there is a need to search for other methods like optimization of the parameters in the circuit that can increase the bandwidth without the need of inductors as it leads to bulky designs and consume a lot of die-space.

Low-noise and high-gain Brillouin optical amplifier for narrowband active optical filtering based on a pump-to-signal optoelectronic tracking.

We implement and characterize an optical narrowband amplifier based on stimulated Brillouin scattering with pump-to-signal relative frequency fluctuations overcome thanks to an active pump tracking. We achieve a precise characterization of this amplifier in terms of gain and noise degradation (noise figure). The performances of this stable selective amplification are compared to those of a conventional erbium-doped fiber amplifier in order to highlight the interest of the Brillouin amplification solution for active narrow optical filtering with a bandpass of 10MHz. Thanks to the simple optoelectronic pump-to-signal tracking, the Brillouin active filter appears as a stable and reliable solution for narrowband optical processing in the coherent optical communication context and optical sensor applications.

A Novel Circuit Model of Small-Signal Amplifier using MOSFETs and BJT in Quadruple Darlington Configuration

circuit model of a small-signal narrow-band amplifier is proposed. The Proposed amplifier is designed using three MOSFETs and a BJT in quadruple Darlington configuration. The proposed circuit successfully amplifies small-signals of 1-10mV range and simultaneously provides high voltage gain and current gain with narrow bandwidth. In this way the proposed design achieved excellent results. Qualitative performance of the proposed amplifier is also compared with the circuit which is having BJT-MOSFET in Darlington pair configuration and with the circuit which is having BJT-MOSFETs in Darlington triple configuration. The proposed amplifier can be used to process audio range signal excursions and may be useful for those applications where high voltage and current gain would be the prime requirement of amplification in narrow-band low frequency region. The qualitative and tuning performance offer a flexible application to these amplifiers to be used as high voltage gain, high power gain and tuned amplifiers. .

Effect of Fluorescent Particle Size on the Modulation Efficiency of Ultrasound-Modulated Fluorescence

To investigate whether the size of fluorescent particles affects the modulation efficiency of ultrasound-modulated fluorescence (UMF), we measured UMF and DC (direct current) signals of the fluorescence emission from four different sized fluorescent particles: (1) three carboxylate-modified fluorescent microspheres (FM) with diameters of 20 nm, 200 nm, and 1.0 µm and (2) streptavidin-conjugated Alexa Fluor 647 with a diameter of approximately 5 nm. The UMF and DC signals were simultaneously measured using a broadband lock-in amplifier and a narrowband amplifier, respectively. The ratio of the UMF strength to the DC signal strength is defined as the modulation efficiency. This modulation efficiency was then used to evaluate the effects of fluorophore size and concentration. Results show that the modulation efficiency was improved by approximately a factor of two when the size of the fluorescent particles is increased from 5 nm to 1 µm. In addition, the linear relationship between the UMF strength and ultrasound pressure (observed in our previous study) were maintained regardless of the fluorescent particle sizes.

A 500 Mb/s Differential Input Non-coherent BPSK Receiver for UWB-IR Communication

A differential input non-coherent BPSK receiver for the UWB-IR communication, based on threshold detection, has been presented in this paper. The chip can recover BPSK modulated Gaussian monocycle pulses (GMP), along with its first derivative, at a data rate of 500 Mb/s. No clock reception is required, as the receiver recovers data based on the relative phase of the two simultaneously received inputs. While retrieving the data, it consumes a power of 63 mW from a supply voltage of 1.8 V. A shunt-peaked narrow band amplifier, matched to the input antenna, is used to amplify the received GMP. Wireless data have been successfully recovered using a pair of horn antennas at a distance of 6 cm. The chip, developed in a 180 nm CMOS technology, occupies a die area of 3.4 mm 2 . The receiver is suitable for the non-coherent (self-synchronized) UWB-IR communication.

A 0.7 V 850 μW CMOS LNA for UHF RFID reader

The design of a narrow-band cascoded CMOS inductive source-degenerated low noise amplifier (LNA) for 866 MHz UHF RFID reader is presented. Compared to other previously reported narrow-band LNA designs, in this work the finite gds (= 1/r0) effect has been considered to improve the nanometric design, achieving simultaneous impedance and minimum Fmin noise matching at a very low power drain of 850 μW from a 0.7-V supply voltage. The LNA was fabricated using the IBM 130 nm CMOS process delivering a power gain (S21) of ≈12 dB, a reverse isolation (S12) of ≈−34 dB, and an input power reflection (S11@866 MHz) of ≈−12 dB. It had a minimum pass-band NF of around 2.2 dB and a 3rd order input referred intercept point (IIP3) of ≈−9.5 dBm. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52:2780–2782, 2010; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25600

Intermodulation distortion in narrowband amplifier circuits

The contribution of bandpass filter memory to intermodulation distortion in narrowband amplifier circuits is examined. A method for generating multisines from filtered switched tones is presented, and techniques for measuring an amplifier's IP3 and extracting a filter's passband using these multisines are developed. It is shown that amplified filtered pulses produce intermodulation distortion in frequency-hopping communication systems. In the experimental study, 465 and 900-MHz Chebyshev bandpass filters are considered.

An Integration Technology for RF and Microwave Circuits Based on Interconnect Programming

<para xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> A configurable integration technology suitable for implementing application specific radio-frequency (RF) and microwave circuits is presented. This postfabrication integration scheme is compatible with complementary metal–oxide–semiconductor (CMOS) technology and utilizes room temperature deposited Parylene-N as low loss and low permittivity dielectric material. Interconnect lines, inductors, and transmission lines fabricated on top of arrays of prefabricated 0.13 <formula formulatype="inline"><tex Notation="TeX">$\mu{\hbox {m}}$</tex></formula> and 90 nm CMOS transistors coated with Parylene-N are configured to design interconnect programmable RF and microwave circuits. The technology is used to demonstrate three proof of concept interconnect programmable narrowband amplifiers. These amplifiers have center frequencies of 5.5, 6.4, and 18 GHz with forward gain <formula formulatype="inline"><tex Notation="TeX">${\rm S}_{21}$</tex></formula> of 16.6, 11, and 18.7 dB, respectively. Fabrication simplicity and programmable nature of this technology compared to standard application specific integrated circuit (ASIC) fabrication lowers the cost and time to market of individual ASIC chip. </para>

Model for a Torsional-Mode Ultrasonic Transducer for an Acousto-Optic In-Fiber Isolator

Torsional ultrasound modes can couple the optical polarization states in a birefringent fiber. Polarization coupling produced by interaction with a higher-order torsional mode slightly above its cutoff may provide a route to producing an in-fiber isolator suitable for use in narrow-band high-power fiber amplifiers. This paper describes a model of a transducer generating torsional modes in a cylindrical fiber. This model predicts that almost all of the power applied to the transducer is radiated into the desired mode. The paper also discusses effects produced by acoustic absorption and the dependence of the acoustic velocity on temperature.

A 12 dB 0.7 V W CMOS LNA for 866 MHz UHF RFID Reader

The design of a narrow-band cascode CMOS inductive source-degenerated low noise amplifier (LNA) for 866 MHz UHF RFID reader is presented. Compared to other previously reported narrow-band LNA designs, in this paper the finite effect has been considered to improve the nanometric design, achieving simultaneous impedance and minimum noise matching at a very low power drain of 850 from a 0.7 V supply voltage. The LNA was fabricated using the IBM 130 nm CMOS process delivering a forward power gain () of , a reverse isolation () of , an output power reflection ( @866 MHz) of , and an input power reflection ( @866 MHz) of . It had a minimum pass-band of around 2.2 dB and a third-order input referred intercept point (IIP3) of .

Stability Improvement of 60 GHz Narrowband Amplifier Using Microstrip Coupled Lines

We present an analysis of microstrip coupled lines (MCLs) used to improve the stability of a 60 GHz narrowband amplifier. The circuit has a 4-stage structure implementing MCLs instead of metal-insulator-metal (MIM) capacitors for the unconditional stability of the amplifier and yield enhancement. The stability parameter, U, is used to compare the stability of MCLs with that of MIM capacitors. Experimental results show that MCLs are more stable than MIM capacitors with the same capacitances as MCLs because the parasitic parallel resistances of MCLs are lower than those of MIM capacitors. Moreover, the bandwidth of an amplifier using MCLs is narrower than one using MIM capacitors because the parasitic series inductances of MCLs are higher than those of MIM capacitors.

Blocker filtering low-noise amplifier for SAW-less Bluetooth receiver system

A 2.4 GHz CMOS blocker filtering low-noise amplifier (BF-LNA) suitable for Bluetooth™ application is presented. The circuit employs a differential amplifier topology with a current mirror active load and a notch filter. Each path amplifies differentially with the common mode input signal, but there is a notch filter rejecting only the wanted signal at one path. By subtracting the two signals from each path, the large interferers are rejected and only the wanted signal is amplified. Therefore, it becomes a narrow-band amplifier with blocker filtering capability, realizing a receiver system without need of the off-chip SAW filter. The BF-LNA is designed using a 0.13-μm CMOS process. The measured performances are a gain of 11.4 dB, and a noise figure of 1.85 dB. Attenuation levels at 400 MHz apart from the target frequency are −13 and −29 dBc at each sideband. The P1dB,in and IIP3 are −8.2 and 1.46 dBm, respectively. The proposed BF-LNA can reject large interferers at the front-end of the receiver system with a good noise figure.

Design techniques for reducing the impact of component variations on narrow-band low noise amplifiers

Given the increasing demand for integrated wireless systems in system-on-chip technology, narrow-band low noise amplifier (LNA) designs must be robust against variations in device parameters and passive component values to improve manufacturing yield for high volume applications. In this paper, we develop two design techniques for reducing the impact of component variations on narrow-band LNA performance. The results demonstrate that by increasing the bandwidth of the narrow-band LNA and applying more conservative design constraints, we can mitigate the reliability implications of process variations on impedance matching, gain, and power consumption.

Radio frequency analog electronics based on carbon nanotube transistors

The potential to exploit single-walled carbon nanotubes (SWNTs) in advanced electronics represents a continuing, major source of interest in these materials. However, scalable integration of SWNTs into circuits is challenging because of difficulties in controlling the geometries, spatial positions, and electronic properties of individual tubes. We have implemented solutions to some of these challenges to yield radio frequency (RF) SWNT analog electronic devices, such as narrow band amplifiers operating in the VHF frequency band with power gains as high as 14 dB. As a demonstration, we fabricated nanotube transistor radios, in which SWNT devices provide all of the key functions, including resonant antennas, fixed RF amplifiers, RF mixers, and audio amplifiers. These results represent important first steps to practical implementation of SWNTs in high-speed analog circuits. Comparison studies indicate certain performance advantages over silicon and capabilities that complement those in existing compound semiconductor technologies.

A 0.18-$\mu{\hbox {m}}$ CMOS Balanced Amplifier for 24-GHz Applications

A 24-GHz balanced amplifier (BA) with a 45-dB gain is realized in 0.18-mum CMOS technology. An effective technique, pi-type parallel resonance, is proposed to boost the high-frequency gain of a MOSFET by resonating out the inherent capacitances. The miniaturized lumped-element coupler in the circuit occupies a chip area of only ~2% compared to that of the conventional transmission-line coupler. The BA consumes 123 mW from a supply voltage of 1 V. To the best of the authors' knowledge, the proposed CMOS BA presents the highest gain of 45.0 dB with a chip area of 0.97 times 0.63 mm2 (core area: 0.78 times 0.43 mm2) among the published narrowband amplifiers with similar technologies and operation frequencies.

Narrowband amplifier with excellent power combining efficiency

Based on a coaxial waveguide power-dividing/combining circuit, a four-device solid-state power amplifier with excellent power combining efficiency is presented. The fabricated power amplifier combining four monolithic microwave integrated circuit power amplifiers shows a 13–16.65 dB small-signal gain over a wide bandwidth of 7–13.5 GHz. The measured maximum output power at 1 dB compression is 25.4 dBm at 11 GHz, with a power-combining efficiency of 91%.

Parasitic-aware analytical modeling of integrated CMOS inductively degenerated narrow-band low noise amplifiers

In this paper, we present an analytical modeling methodology for fully integrated inductively-degenerated CMOS narrow-band cascode Low Noise Amplifiers (LNA) that captures short channel transistor effects to enable rapid design space exploration in current and future process technologies. The modeling methodology captures the impact of parasitics on passive components, ESD-protection structures, and devices to accurately predict both impedance matching and noise figure. Our modeling is suitable for numerical optimization and fully automated synthesis for LNAs. The results indicate that the methodology models ESD-protected LNA circuits with 47.9% better accuracy in noise figure when compared with several current analytical modeling techniques with four orders of magnitude improvement in simulation time over circuit-level simulation. Given its speed and accuracy, the analytical modeling methodology is well-suited for design space exploration.

Frequency and phase modulation performance of an injection-locked CW magnetron

It is demonstrated that the output of a 2.45-GHz magnetron operated as a current-controlled oscillator through its pushing characteristic can lock to injection signals in times of the order of 100-500 ns depending on injection power, magnetron heater power, load impedance, and frequency offset of the injection frequency from the natural frequency of the magnetron. Accordingly, the magnetron can follow frequency and phase modulations of the injection signal, behaving as a narrow-band amplifier. The transmission of phase-shift-keyed data at 2 Mb/s has been achieved. Measurements of the frequency response and anode current after a switch of phase as a function of average anode current and heater power give new insight into the locking mechanisms and the noise characteristics of magnetrons