Quadrature Voltage Research Articles

Voltage-Mode and Current-Mode Resistorless Third-Order Quadrature Oscillator

This paper presents the realization of a resistorless third-order quadrature oscillator using two multiple-output current controlled current conveyor transconductance amplifiers (MO-CCCCTAs) and three grounded capacitors. The proposed circuit provides two quadrature voltage outputs, two high-impedance quadrature current outputs, and one high-impedance amplitude-controllable current output. The proposed oscillator satisfies the industrial requirement for amplifier and modulation signals and phase shift keying signals, when the input bias current of the second MO-CCCCTA is used as a modulating signal. Its oscillation condition and oscillation frequency can be adjusted independently by two different bias currents of MO-CCCCTAs. The structure of resistorless and only grounded capacitors suggests that the proposed oscillator can be easily implemented in an integrated circuit.

Voltage-Mode Third-Order Quadrature Sinusoidal Oscillator Using VDBAs

This paper presents a third-order quadrature sinusoidal oscillator (TOQSO) using two voltage differencing buffered amplifiers (VDBAs), three capacitors and a resistor. The new topology provides two quadrature voltage outputs. The condition of oscillation (CO) and frequency of oscillation (FO) are electronically independently controllable by the separate transconductance of the VDBAs. The workability of the proposed TOQSO is confirmed by SPICE (Version 16.5) simulation using Taiwan semiconductor manufacturing company (TSMC) 0.18 μm process parameters.

Compact electronically tunable quadrature oscillator using single voltage differencing gain amplifier (VDGA) and all grounded passive elements

This work deals with the design of a compact electronically tunable sinusoidal quadrature oscillator. The proposed quadrature oscillator is designed with a single voltage differencing gain amplifier (VDGA) and all the three grounded passive elements. Its oscillation condition and oscillation frequency can be tuned independently by means of the VDGA transconductance gains. The proposed oscillator also provides the explicit quadrature voltage outputs of almost equal magnitude and low active and passive sensitivity figures. The performance of the oscillator has been demonstrated by PSPICE simulations based on TSMC 0.35-$\mu $m CMOS technology.

System simulations of a 1.5\xa0V SiGe 81\u201386\xa0GHz E-band transmitter

This paper presents simulation results for a sliding-IF SiGe E-band transmitter circuit for the 81–86 GHz E-band. The circuit was designed in a SiGe process with fT = 200 GHz and uses a supply of 1.5 V. The low supply voltage eliminates the need for a dedicated transmitter voltage regulator. The carrier generation is based on a 28 GHz quadrature voltage oscillator (QVCO). Upconversion to 84 GHz is performed by first mixing with the QVCO signals, converting the signal from baseband to 28 GHz, and then mixing it with the 56 GHz QVCO second harmonic, present at the emitter nodes of the QVCO core devices. The second mixer is connected to a three-stage power amplifier utilizing capacitive cross-coupling to increase the gain, providing a saturated output power of +14 dBm with a 1 dB output compression point of +11 dBm. E-band radio links using higher order modulation, e.g. 64 QAM, are sensitive to I/Q phase errors. The presented design is based on a 28 GHz QVCO, the lower frequency reducing the phase error due to mismatch in active and passive devices. The I/Q mismatch can be further reduced by adjusting varactors connected to each QVCO output. The analog performance of the transmitter is based on ADS Momentum models of all inductors and transformers, and layout parasitic extracted views of the active parts. For the simulations with a 16 QAM modulated baseband input signal, however, the Momentum models were replaced with lumped equivalent models to ease simulator convergence. Constellation diagrams and error vector magnitude (EVM) were calculated in MATLAB using data from transient simulations. The EVM dependency on QVCO phase noise, I/Q imbalance and PA compression has been analyzed. For an average output power of 7.5 dBm, the design achieves 7.2% EVM for a 16 QAM signal with 1 GHz bandwidth. The current consumption of the transmitter, including the PA, equals 131 mA from a 1.5 V supply.

Novel CMOS Current Inverting Differential Input Transconductance Amplifier and Its Application

This paper presents the complementary metal oxide semiconductor (CMOS) implementation of active building block, namely, current inverting differential input transconductance amplifier (CIDITA) along with its performance parameters. The detailed study of the proposed CMOS CIDITA has been incorporated. The presented study shows the good performance of CIDITA in terms of good bandwidth range, good linear range of input current, high accuracy and low operating voltage. A new circuit of single active element-based quadrature oscillator is further realized to explore the workability of CIDITA. The proposed circuit of quadrature oscillator employs two grounded capacitors, one resistor and single CIDITA. The proposed quadrature oscillator provides both quadrature current outputs and quadrature voltage outputs simultaneously. The frequency of oscillation of the proposed quadrature oscillator is electronically controllable. The possible practical realization of the CIDITA using commercially available ICs is also given. HSPICE simulation results using 0.18[Formula: see text][Formula: see text]m CMOS parameters are given to validate the proposed theory.

Modeling and Diagnostic of Incipient Interturn Faults for a Three-Phase Permanent Magnet Synchronous Motor

This paper discusses incipient end-winding interturn faults in the stator winding of a permanent magnet synchronous motor caused by the mechanical vibrations of the concerned turns. With aging, the end-winding blocking system becomes weaker and turns insulation degrades until its breakdown. The fault is modeled by an intermittent interturn short circuit between the turns of the stator end winding. Intermittent fault occurrence disturbs the stator currents as well as the reference voltages leaving a specific fault signature. The detection method uses a pattern-adapted wavelet to detect fault occurrence. In this paper, it is applied to the quadrature reference voltage. Simulation and experimental results confirm the effectiveness of the proposed approach.

Low Voltage Mixed-mode Multi Phase Oscillator Using Single FDCCII

In this paper a new low voltage mixed-mode multiphase quadrature oscillator employing a single fully differential second generation current conveyor, two resistors and two grounded capacitors is proposed. The proposed circuit provides two quadrature voltage outputs and three quadrature current outputs simultaneously. In addition, the proposed circuit has been made load insensitive so that it is capable of providing high output impedance current outputs without using additional current followers. Moreover, the proposed circuit of load insensitive quadrature oscillator provides four phase current outputs and two voltage outputs, simultaneously. Non ideal study is also included. Both the proposed circuits enjoy low active and passive sensitivities. This paper further presents an active-C multiphase oscillator with a single FDCCII and two grounded capacitors. The proposed structures are suitable for low voltage applications. Simulation results using PSPICE program on cadence tool are included.

VDCC Based Dual-Mode Quadrature Sinusoidal Oscillator with Outputs at Appropriate Impedance Levels

This article presents a new dual-mode (i.e. both current-mode and voltage-mode) quadrature sinusoidal oscillator using two Voltage Differencing Current Conveyors (VDCCs), two resistors and two capacitors. The proposed configuration use only grounded passive elements and enjoys independent resistor/electronic tuning of both Condition of Oscillation (CO) as well as Frequency of Oscillation (FO). The quadrature current and voltage mode outputs of this circuit are available at appropriate impedance terminals. The behavior of presented oscillator is also examined under non ideal/parasitic conditions. The validity of the proposed configuration has been confirmed by SPICE simulations with TSMC 0.18μm process parameters.

Wide band low phase noise QVCO based on superharmonic injection locking**Project supporteded by the National Natural Science Foundation of China (No. 41274047) and the Guangdong Province Science and Technology Program (No. 2013B090500049).

A wide band, injection-coupled LC quadrature voltage control oscillator is presented. In the proposed circuit, two oscillators are injection locked by coupling their second-order harmonics in anti-phase, forcing the outputs of two oscillators into a quadrature phase state. As the common-mode point sampling the second harmonic frequency, flicker noise of the tail current is suppressed, the phase noise is reduced. The proposed design accomplishes a wide tuning frequency range by a combination of using a 5-bit switch capacitor array (SCA) for discrete tuning in addition to linearly varying AMOS varactors for continuous tuning. The proposed design has been fabricated and verified in a 0.18 μm TSMC CMOS technology process. The measurement indicates that the quadrature voltage controlled oscillator has a 41.7% tuning range from 3.53 to 5.39 GHz. The measured phase noise is 127.98 dBc/Hz at 1 MHz offset at a 1.8 V supply voltage with a power consumption of 12 mW at a carrier frequency of 4.85 GHz.

Design of Wideband Low Phase Noise Class-C QVCO With Low Amplitude and Phase Errors

This letter presents a wideband, low phase noise, quadrature voltage controlled oscillator (QVCO) implemented in 0.18 $\mu{\rm m}$ CMOS. In order to improve the phase noise while provide high efficient oscillation, the cooperation of a Class-C operation with a bulk-coupled structure are adopted into a PMOS-only VCO. With high fundamental current amplitude generated and the frequency offset of the QVCO alleviated, the phase noise is improved significantly. The measurement shows 2–8 dB phase noise improvement with a minimum value of $-124 ~{\rm dBc}/{\rm Hz}$ at 1 MHz offset. Wide tuning range of 22.6% is realized by four-bit switched-capacitor-array ranging from 5.6 to 6.9 GHz. The quadrature accuracy of the proposed QVCO is evaluated by the measured results of an image-rejection mixer (IR-mixer), which exhibits a peak image rejection ratio (IRR) of 40 dBc, indicating low amplitude and phase errors simultaneously.

A 3D-HARPSS Polysilicon Microhemispherical Shell Resonating Gyroscope: Design, Fabrication, and Characterization

This paper presents, for the first time, the analysis, design, fabrication, and characterization of a microhemispherical resonating gyroscope ( $\mu $ HRG). A 3D high aspect-ratio poly- and single-crystalline silicon (HARPSS) process is developed to fabricate a stem-supported hemispherical shell with self-aligned tall capacitive electrodes intended for driving, sensing, and tuning of the gyroscope. The monolithic process consists of seven lithographic steps combining the HARPSS process with fabrication of a 3D curved microstructure to create electrodes with scalable capacitive gaps. The fabrication is successfully demonstrated with polysilicon $\mu $ HRG prototypes with a diameter of 1.2 mm and a shell thickness of 1 $\mu \text{m}$ . The frequency response is measured and gyro operation is examined using the integrated electrodes. Mode matching and mode alignment are successfully performed by applying tuning and quadrature nulling voltages. A closed-loop rate sensitivity scale factor of 8.57 mV/°/s was measured. Furthermore, design and process optimization of the support structure resulted in an improved quality factor ( $Q \sim 40\,000$ ).

A Control Method for Inverter-Based Islanded Microgrids Based on V-I Droop Characteristics

Microgrids' performance and stability mostly depend on power-flow control strategy. In order to allow for coordinated control while maintaining reliable operation, decentralized control methods based on P and Q droop characteristics have been utilized. Inherently, the power droop control methods have slow dynamics. In this paper, a novel control method based on V-I characteristics is introduced to exploit the flexibility and fast dynamics of the inverter-based distributed energy resources. In the proposed method, the direct and quadrature axis voltage components are drooped with the corresponding currents according to a piecewise linear droop function. Eigenvalue analysis of a sample microgrid shows that the proposed method features faster dynamics and improved damping compared to the conventional droop scheme. Simulation results are presented to verify the efficacy of the proposed method.

New canonic lossy inductor using a single CDBA and its application

A new lossy inductor (parallel R-L type) using single current differencing buffered amplifier (CDBA) is presented, which employs only two resistors and a grounded capacitor. The proposed lossy inductor is shown to be useful in realizing an oscillator circuit, which provides quadrature voltage outputs using only two CDBAs, three resistors and two grounded capacitors and offers independent control on condition of oscillation and frequency of oscillation up to a frequency of 61 MHz. Detailed non-ideal analysis including single-pole model for voltage and current gain has also been carried out. SPICE simulation results and experimental results based upon the CDBA constructed from commercially available IC AD844 have been included which confirm the practical workability of the proposed lossy inductor and quadrature oscillator circuit.

Adoption of Park’s Transformation for Inverter Fed Drive

Park’s transformation in the context of ac machine is applied to obtain quadrature voltages for the 3-phase balanced voltages. In the case of a inverter fed drive, one can adopt Park’s transformation to directly derive the quadrature voltages in terms simplified functions of switching parameters. This is the main result of the paper which can be applied to model based and predictive control of electrical machines. Simulation results are used to compare the new dq voltage modelling response to conventional direct –quadrature (dq) axes modelling response in direct torque control – space vector modulation scheme. The proposed model is compact, decreases the computation complexity and time. The model is useful especially in model based control implemented in real time, in terms of a simplified set of switching parameters.

A Capacitive Rotary Encoder Based on Quadrature Modulation and Demodulation

This paper presents a capacitive rotary encoder for both angular position and angular speed measurements. The encoder is mainly composed of three parts: the transmitting segments; a pair of reflecting electrodes; and a pair of receiving electrodes. The transmitting segments together with four mutual quadrature carrier voltages provide a modulated electric field. The reflecting electrodes, which are patterned sinusoidally can encode the angular position to a phase/frequency modulated signal based on quadrature modulation. The modulated signal is then digitally decoded to the angular position in a field programmable gate array processor based on the quadrature demodulation and the coordinate rotational digital computer algorithm. Through a universal serial bus, the digital angular position is transmitted to a computer for further analysis in National Instruments' LabVIEW software. A prototype of the capacitive encoder shows that its precision is better than 0.006° and the resolution is 0.002°. The dynamic nonlinearity is evaluated at ±0.4° when the rotor is rotating at 1000 r/min.

A Phase-shifter for Regulating Circulating Power Flow in a Parallel-feeding AC Traction Power System

A parallel-feeding AC traction power system increases the power supply capacity and decreases voltage fluctuations, but the circulating power flow caused by the phase difference between the traction substations prevents the system from being widely used. A circuit analysis shows that the circulating power flow increases almost linearly as the phase difference increases, which adds extra load to the system and results in increased power dissipation and load unbalance. In this paper, we suggest a phase shifter for the parallel-feeding AC traction power system. The phase shifter regulates the phase difference and the circulating power flow by injecting quadrature voltage which can be obtained directly from the Scott-connection transformer in the traction substation. A case study involving the phase shifter applied to the traction power system of a Korean high-speed rail system shows that a three-level phase shifter can prevent circulating power flow while the phase difference between substations increases up to 12 degrees, mitigate the load unbalance, and reduce power dissipation.

A 6-GHz capacitively-coupled Colpitts CMOS quadrature voltage controlled oscillator

In this work a new low-noise low-power Colpitts quadrature voltage controlled oscillator (QVCO) made by coupling two identical current-switching differential Colpitts voltage controlled oscillators...

Electronically tunable quadrature oscillator using grounded components with current and voltage outputs.

The electronically tunable quadrature oscillator using a single multiple-output current controlled current differencing transconductance amplifier (MO-CCCDTA) and grounded passive components is presented. The proposed configuration uses a single MO-CCCDTA, two grounded capacitors and one grounded resistor. Two high-output impedance quadrature current signals and two quadrature voltage signals with 90° phase difference. The oscillation condition and oscillation frequency of the proposed quadrature oscillator are independently controllable. The use of only grounded passive components makes the proposed circuit ideal for integrated circuit implementation.

Tunable current-mode and voltage-mode quadrature oscillator using a DVCCTA

A novel tunable current-mode and voltage-mode quadrature oscillator design using a single differential voltage current conveyor transconductance amplifier (DVCCTA) and four all grounded passive elements is presented. The proposed circuit offers two explicit quadrature current outputs and two quadrature voltage outputs. The oscillation condition and oscillation frequency of the proposed oscillator are independently controllable. The use of only grounded passive components makes the proposed circuit ideal for integrated circuit implementation. HSPICE simulation results are given to verify the theoretical analysis.

Ultra‐low‐phase‐noise CMOS LC quadrature voltage controlled oscillator with Colpitts topology

A new low-phase-noise colpitts LC quadrature voltage controlled oscillator (QVCO) is presented. The proposed QVCO is realised by coupling two differential current-switching Colpitts oscillators in an ‘in-phase–anti-phase’ manner. The coupling technique between the two Colpitts LC-voltage controlled oscillators (VCOs) has significantly improved the phase noise of the proposed circuit without using any extra elements. The oscillation frequency of the proposed LC-QVCO is 4 GHz. The Colpitts QVCO exhibits a phase noise of −131.5 and −141.3 dBc/Hz at 1 and 3 MHz offset, respectively. By generalising the coupling scheme to more than two differential Colpitts VCOs in a loop, multiphase signals can be generated.