Control Of Quality Factor Research Articles

Grounded capacitor based fully cascadable electronically tunable current-mode universal filter

A novel current-mode (CM) universal filter configuration composed of five plus-type second-generation current conveyors (CCII+s) as active components besides three resistors and three grounded capacitors as passive elements is proposed in this paper. The proposed filter can simultaneously provide high-pass, band-pass and low-pass responses. Also, it can realize all-pass and notch responses with interconnection of convenient output currents. It can be cascaded with other CM ones easily because it has low input and high output impedances. It offers orthogonal control of angular resonance frequency and quality factor. An electronically tunable universal filter can be easily obtained if plus-type current controlled current conveyors are replaced instead of each of the five CCII+s and all the three resistors are removed. Nevertheless, it needs a single passive element matching constraint for notch and all-pass filter responses. Some simulation and experimental test results are included to confirm the theory.

3D microwave cavity with magnetic flux control and enhanced quality factor

Three-dimensional (3D) microwave cavities have been extensively used for coupling and interacting with superconducting quantum bits (qubits), providing a versatile platform for quantum control experiments and for realizing hybrid quantum systems. While having high quality factors (>106) superconducting cavities do not permit magnetic field control of qubits. In contrast, cavities made of normal metals are transparent to magnetic fields, but experience lower quality factors (∼104). We have created a hybrid cavity which is primarily composed of aluminium but also contains a small copper insert reaching the internal quality factor of ≃105, an order of magnitude improvement over all previously tested normal metal cavities. In order to demonstrate precise magnetic control, we performed spectroscopy of three superconducting qubits, where individual control of each qubit’s frequency was exerted with small external wire coils. An improvement in quality factor and magnetic field control makes this 3D hybrid cavity an attractive new element for circuit quantum electrodynamics experiments.

Differential Second-Order Voltage-Mode All-Pass Filter Using Current Conveyors

In this paper, a new circuit solution of analogue pseudo-differential second-order all-pass filter operating in the voltage mode is presented. Pseudo-differential, since both input and output terminals are differential, however, the circuit topology features single-ended structure. As active elements the differential difference current conveyors and second-generation current conveyors are advantageously used. The proposed filter features quality factor control without disturbing the pole-frequency using single passive element. The designed circuit is less complex compared to fully-differential solutions by maintaining sufficient common-mode rejection ratio. The behaviour of the filter is described by means of symbolic analysis and also by simulations using the UCC-N1B integrated circuit. Furthermore, the performance of the proposed pseudo-differential filter has been validated by experimental measurements.DOI: http://dx.doi.org/10.5755/j01.eie.22.5.16344

Second-Order Voltage-Mode Universal Filters Using Two DVCCs, Two Grounded Capacitors and Four Resistors

In this paper, two new second-order voltage-mode universal filters are proposed. Both of the proposed filters use only two differential voltage current conveyors (DVCCs), four resistors and two grounded capacitors which are advantageous from integrated circuit technology point of view. They can simultaneously provide second-order low-pass, high-pass, band-pass, notch and all-pass responses. They offer orthogonal control of angular resonance frequency and quality factor. However, they have a single matching condition for only all-pass responses. A number of simulations based on SPICE program are accomplished in order to demonstrate the performance of both filters.

Reconnection-less OTA-based Biquad Filter with Electronically Reconfigurable Transfers

This paper deals with operational transconductance amplifiers (OTAs) -based active voltage-mode biquad filter with electronically reconfigurable transfer functions. Due to utilization of the very favourable active devices, this design is ready for immediate CMOS design. Presented filtering solution contains four active elements where each of them is directly used for reconnection-less change of transfer function or modification including electronic control of quality factor and tuning. The filter offers availability of all-pass, high-pass, band-pass, band-reject transfer response and special transfers as high-pass with zero and low-pass with zero. Measurement results based on utilization of diamond transistors confirmed expected behaviour of the circuit. DOI: http://dx.doi.org/10.5755/j01.eee.21.3.10205

A ± 0.2 V, 0.12 μW CCTA USING VTMOS AND AN APPLICATION FRACTIONAL-ORDER UNIVERSAL FILTER

In this paper, a variable threshold voltage metal oxide semiconductor (VTMOS) field effect transistor is used to improve an ultra-low voltage, ultra-low power current conveyor transconductance amplifier (CCTA). To achieve the desired result, an analytical subthreshold VTMOS model is used. Designs that utilize the TSMC 0.18 μm technology are verified using PSPICE simulation. The power consumption is simply 0.12 μW at a ± 0.2 V supply voltage. The proposed CCTA is synthesized using fractional-order (FO) universal filters that can simultaneously realise low pass (LP), high pass (HP) and bandpass (BP) responses with independent control of quality factor and pole frequency by transconductances (gm). Moreover, the circuit has low input and high output impedance which would be an ideal choice for cascading in current-mode circuit. The FO filters are constructed using two FO capacitors of orders α and β (0 < α, β ≤ 1). The FO filters provide improved performance in terms of pole frequency compared with conventional-order filters. The filter has a low power consumption of 0.71 μW at a ± 0.2 V supply voltage. The validity of the proposed filter is verified through PSPICE simulations.

Electronically controlled high input and low output impedance voltage mode multifunction filter with grounded capacitors

In this study, a three-input single-output voltage-mode biquadratic filter employing voltage differencing differential input buffered amplifier (VD-DIBA) is presented. The proposed filter uses two VD-DIBAs and two grounded capacitors without any external resistors, which is well suited for integrated circuit implementation. The circuit provides five standard transfer functions, namely, low pass, high pass, band pass, notch and all pass filters with electronic control of quality factor and pole frequency. Each transfer function can be selected by suitably selecting input signals via digital method. The filter does not require inverting of the input voltage signal. Moreover, the circuit possesses high input and low output impedances and thus it enables simple voltage-mode cascading. The PSPICE simulation and also experimental results are included, verifying the workability of the proposed filter. The given results agree well with the theoretical anticipation.

Voltage-mode multifunction filter with mutually independent Q and $$\omega _0$$ ω 0 control feature using VDDDAs

The paper focuses on the application possibilities of the newly presented voltage differencing active building block called voltage differencing differential difference amplifier. Using this active element, a multifunction frequency filter is designed featuring the possibility of mutually independent control of quality factor Q and characteristic frequency $$\omega _0$$ ? 0 by means of active elements. The structure of the filter is based on the idea of the Akerberg-Mossberg (AM) filter, i.e. the integrators in the structure are always realized only by two active elements. This fact results in better phase compensation for the filter. Compared to the AM opamp based filter, the newly proposed structure features high-impedance inputs, low-impedance output, and all basic frequency responses. The performance of the proposed structure has been verified by SPICE simulations using the TSMC $$0.18\,\upmu \hbox {m}$$ 0.18 μ m level-7 SCN018 CMOS process parameters with $$\pm 0.9\,\hbox {V}$$ ± 0.9 V supply voltage.

3P1-T04 アンテナの仮想Q値制御による磁界共振型距離センサの広域化手法(インテリジェント・ロボティクス・スペース(IT, RTとETの融合))

3P1-T04 アンテナの仮想Q値制御による磁界共振型距離センサの広域化手法(インテリジェント・ロボティクス・スペース(IT, RTとETの融合))

Three Input Single Output Voltage-Mode Multifunction Filter with Independent Control of Pole Frequency and Quality Factor

This paper presents a voltage-mode biquadratic filter performing completely standard functions: low-pass, high-pass, band-pass, band-reject and all-pass functions, based on single voltage differencing transconductance amplifier (VDTA). The proposed filter has three input voltage and a single output voltage. The features of the circuit are that; the quality factor and natural frequency can be tuned independently; the circuit description is very simple, consisting of merely one VDTA, one resistor and two capacitors; the pole frequency can be electronically adjusted. Additionally, each function response can be selected by suitably selecting input signals with digital method; the double input voltage is not required. Using only single active element, the proposed circuit is very suitable to further develop into an integrated circuit. The PSPICE simulation results are depicted. The given results agree well with the theoretical anticipation.

Modulated–demodulated control: Q control of an AFM microcantilever

We outline the application of modulated–demodulated control to the quality (Q) factor control of an atomic force microscope microcantilever. We review the modulated–demodulated control technique, emphasize its linear time invariant nature and develop state space representations of the controller for design and analysis. The modulated–demodulated controller can be configured as both positive position feedback (PPF) and resonant controllers, which are effective in the control of negative imaginary systems. Negative imaginary systems theory has important application in the control of collocated mechanical systems and we briefly summarize the key relevant results. A high-frequency, tunable modulated–demodulated controller, designed specifically for MHz operation, was developed for experimental validation. The modulated–demodulated controller enables the use of a low-bandwidth baseband controller in the configuration of a high-bandwidth controller, thus simplifying the implementation of high-bandwidth controllers. We outline the controller characterization and demonstrate closed-loop control of a Bruker DMASP microcantilever. We also present AFM images highlighting the improvements in scan speed and image quality achieved as a result of Q control. Modulated–demodulated control appears well suited to the control of high-frequency resonant dynamics. In addition to high-speed atomic force microscopy, we believe this control technique may find applications in high-frequency microelectromechanical systems (MEMS).

CDTAs Based Current-Mode Universal Biquad Filters with Orthogonal Control of Quality Factor and Pole Frequency

This article presents current-mode universal biquad filters based on CDTAs. The filter circuits using four CDTAs and two grounded capacitors which are able to provide low-pass, high-pass, band-pass, band-reject and all-pass functions. The pole frequency can be orthogonally controlled from quality factor and the circuits have high output impedance appropriate for cascade connection application in current mode which is capable to directly drive load. This qualification is very appropriate for further development into an integrated circuit. The results of PSPICE simulation program are corresponding to the theoretical analysis.

Electronically tunable current-mode biquad filter employing CCCDTAs and grounded capacitors with low input and high output impedance

In this study, a single-input multiple-outputs current-mode analog biquadratic filter, based on current controlled current differencing transconductance amplifier (CCCDTA) is presented. The proposed filter uses two CCCDTAs and two grounded capacitors without any external resistors, which is well suited for integrated circuit implementation. The filter simultaneously gives 3 standard transfer functions, namely, lowpass, highpass and bandpass filters with independent control of quality factor and pole frequency by electronic method. By summing of IHP and LLP, the notch filter can be also achieved. Moreover, the circuit has low input and high output impedance which would be an ideal choice for cascading in current-mode circuit. The PSPICE simulation results are included verifying the workability of the proposed filter. The given results agree well with the theoretical anticipation.

Modulated-Demodulated Q Control of an Atomic Force Microscope Microcantilever

We outline the application of the modulated-demodulated control technique to the quality (Q) factor control of an atomic force microscope microcantilever. The modulated-demodulated controller developed can be modeled as a linear time invariant controller, which resembles a positive position feedback (PPF) controller. We utilize negative imaginary theory to concisely summarize the requirements for robust stability of the closed loop system. The Q controller is verified experimentally on a microcantilever. Modulated-demodulated control appears to be well suited to the control of high frequency dynamics, simplifying the bandwidth requirements of the baseband controller. Due to the controller parameterization, the tuning process is extremely simple. We believe modulated-demodulated control could find applications in high speed atomic force microscopy (AFM) and microelectromechanical systems (MEMS).

Digitally Programmable Voltage-Mode Universal Biquadratic Filter

A single input multi-output voltage mode universal biquadratic filter has been presented. The circuit incorporates digital programmability employing three plus-type differential voltage current conveyors (DVCCs), two grounded capacitors and three resistors. The circuit exhibits high input impedance realizes all the standard filter functions having orthogonal control of cut-off frequency and quality factor. Parameter tunability is achieved by the use of a 3–bit digital control word. The proposed circuits are amenable for monolithic integration by virtue of the fact that only grounded capacitors are employed. Circuit simulations using PSPICE are in perfect agreement with the theoretically predicted results.

Microwave frequency selective surface with controllable high Q-factor transmission resonance

A thin layer with a high quality factor trapped-mode resonance and control of its resonance frequency is investigated.The structure consists of array of two metal concentric rings in a unit cell supported by a ferrite substrate. We consider magnetization normal to the array plane and two orthogonal in-plane directions. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:2762–2766, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27194

Electronic driver with amplitude and quality factor control to adjust the response of quartz tuning fork sensors in atomic force microscopy applications

Quartz tuning fork-based sensors are self-sensing probes that are gaining popularity in atomic force microscopy. They do not need a laser-photodiode system and they have a higher quality factor in liquid than standard cantilevers. However, the main limitation of tuning fork probes is that they are usually handmade because no commercial probes suitable for a wide range of experiments are available. The handmade devices show considerable variation in dynamic response, thereby hindering the repeatability of experiments. To overcome this problem, here we develop an electronic driver to simultaneously control the quality factor (Q) and the oscillation amplitude (A) of the device. The driver provides clear advantages over classical Q-control modules where the amplitude of oscillation is modified when the Q factor is changed. Direct measurements on a commercial interferometer showed that the effective Q factor can be adjusted to experimental requirements while maintaining the mechanical amplitude of oscillation constant. Experimental amplitude vs. distance curves confirm that our driver achieves an equivalent dynamic response from distinct handmade sensors (with varying mechanical characteristics) by means of electronic adjustment. The driver is a simple but effective method to ensure the same measurement conditions with a range of quartz tuning fork probes and also the reliability and repeatability of experiments.

Self-sensing and quality factor control circuits for piezoelectric millimeter-sized resonant cantilevers

For ever-increasing applications of resonant piezoelectric-excited millimeter-sized cantilever (PEMC) such as biosensors, viscosity, and density sensors, the need for design and implementation of a portable circuit for measuring the resonant frequency shift and/or the variation in the quality factor of PEMC becomes crucial. In this article, active and passive self-sensing bridge circuits are designed, fabricated, and implemented for a PEMC. The performances of these circuits are examined for the resonant frequency and quality factor measurements for vibration of PEMC in two different environments. For this purpose, a parameter-tuning procedure for the passive bridge based on experimental identification of Van Dyke model parameters is proposed and applied for the vibration of PEMC in air and 98% glycerol solution. Also, a compensation method for potential instability of active bridge circuit is proposed and developed experimentally for the vibration of PEMC in these environments. To increase the quality factor, the fabricated passive bridge is used in a designed control circuit, which is based on positive feedback signal proportional to the vibration velocity. The experiments show that with the proposed and implemented control circuit, the quality factor will increase by about 80% in air and 25% in glycerol.

광대역 특성을 갖는 집중 소자를 이용한 고출력 증폭기용 마이크로파 바이어스-티의 설계

본 논문에서는 고출력 증폭기의 바이어스를 위한 대전류 마이크로파 광대역 바이어스-티의 설계를 보였다. DC 블록용 커패시터는 큰 어드미턴스를 가지도록 커패시터의 병렬합을 이용하고, DC 공급 및 RF 초크용 인덕터는 광대역의 큰 임피던스를 가지는 인덕터의 직렬합을 이용하여 설계하였다. DC 블록이나 RF 초크에 사용되는 인덕터나 커패시터는 자기 공진 주파수(SRF: Self Resonance Frequency)를 가지고 있어 사용 대역이 제약된다. 이를 해결하기 위해 RF 초크에서는 저항을 추가하여 공진 주파수에서 품질 계수를 조정함으로써 해결하였다. 그리고 DC 블록에서는 별도의 품질 계수 조정없이 병렬합만으로 가능하였다. 이 결과를 이용하여 1608 칩 형태의 집중 소자들을 표면 실장 기법(surface mount)으로 PCB 패턴에 조립하여 바이어스-티를 제작하였다. 제작된 바이어스-티는 10 MHz~10 GHz에서 측정된 반사 손실이 10 dB 이하를 가지며, 입력 임피던스는 광대역에서 50 ohm 근처의 값을 만족하는 것을 확인하였다. In this paper, a design of high current and broad-band microwave bias-tee was presented for a stable bias of a high power amplifier. An input impedance of bias-tee should be shown to 50 ohm with the wideband in order to be stably-biased the amplifier. For this design of the bias-tee, a capacitor of bias-tee for a DC block was designed with a high wide-band admittance by a parallel sum of capacitors, and a inductor for a RF choke and a DC feeding was designed with a high wide-band impedance by a series sum of inductors. As this inductor and capacitor for the sum has each SRF, band-limitation of lumped element was driven from SRF. This limitation was overcome by control of a resonance's quality factor with adding a resistor. 1608 SMD chips for design's element was mounted on the this pattern for the designed bias-tee. The fabricated bias-tee presented 10 dB of return loss and wide-band about 50 ohm input impedance at 10 MHz~10 GHz.

Fabrication and quality factor control of a microelectromechanical system resonator with linear differential drive

The fabrication, characterisation and quality factor control of a microelectromechanical system resonator with differential drive and readout is reported. The differential drive results in a linear relationship between the AC drive voltage and the applied force. Furthermore, the static DC force and the undesirable force at the second harmonic frequency (introduced by other driving methods) are also reduced. Differential readout is employed in order to minimise undesirable common-mode signals in the detection electronics. The device has been fabricated in silicon on insulator (using the Integram high aspect ratio micromachining process at QinetiQ) and fully characterised. The ability to track the resonant frequency with fine resolution is related to the quality factor of the resonant system. Commonly used detection techniques such as slope detection and phase detection both require a high quality factor, however, resistance to motion caused by air damping results in a low quality factor – degrading the performance of the sensor. The low-pressure quality factor is measured as being >5500 and reduces to ∼10 at atmospheric pressure. The linear relationship between AC drive voltage and resultant force is exploited in conjunction with an electronic readout architecture yielding the device velocity to implement a force feedback technique – increasing the quality factor of the resonator.