Quadrature Oscillator Research Articles

A novel triangular wave quadrature oscillator without passive components for sinusoidal pulse width modulation DC-AC power conversion

In this study, a low-cost quadrature triangle oscillator using a voltage-controlled closed-loop dual operational amplifier (Op-Amp) architecture is proposed. Unlike other typical designs, this oscillator does not require any passive components. The use of an Op-Amp-based circuit is attractive for a triangle oscillator because it is more cost-effective than a microcontroller-based solution. This is especially true for sinusoidal pulse width modulation (SPWM) DC-AC power conversion applications. The slew-rate restriction of an Op-Amp is a useful characteristic for producing a triangle waveform when seen from the perspective of wave shaping techniques. The MC4558 and the JRC4558D are two examples of dual Op-Amps that are evaluated, contrasted, and described in this article. At supply voltages of +7 V and -7 V, the suggested quadrature triangle oscillator that uses Op-Amps MC4558 and JRC4558D has the same oscillation frequency, which is 63 kHz, as demonstrated by simulation and experimental data. The frequency stability is estimated to be around 0.23%. In addition, the findings from the experiment demonstrate that the proposed oscillator is a practical solution for the SPWM DC-AC power conversion application.

Electronically Tunable Differential Difference Current Conveyor Using Commercially Available OTAS

This paper presents a new electronically tunable differential difference current conveyor (EDDCC) using the commercially available operational transconductance amplifiers (OTAs). Unlike the conventional DDCC, the proposed EDDCC offers current gain that can be electronically controlled. The EDDCC can be used to realize a new electronically tunable fully differential difference second-generation current conveyor (EFDCCII). Therefore, the current gain of the proposed EFDCCII can be electronically controlled. To show the advantages of the proposed EDDCC and EFDCCII, the EDDCC has been used to realize a quadrature oscillator and the EFDCCII has been used to realize a current-mode universal filter. The proposed circuits have been investigated by simulation and experimental tests using the commercially available LM13700 OTAs.

A novel PMOS transistors based first-order all-pass network

In this paper, a new voltage-mode first-order all-pass network is introduced. It is realized by using only four p-channel metal–oxide–semiconductor transistors, one resistor and one capacitor. The proposed filter enjoys the feature of high input impedance and does not require any additional current source. It is also free from any kind of passive element matching constraint. In order to test the workability of the proposed structure, a second-order all-pass network and quadrature oscillator are presented. Personal simulation program with integrated circuit emphasis using 0.18 µm, level-7 complementary metal-oxide-semiconductor process parameters with ± 0.9 V supply voltages are used to validate the performance of the proposed structure.

Dual-Mode Single-Input Three-Output Multifunction Filter and Quadrature Oscillator Consisting of Two Voltage Differencing Transconductance Amplifiers and Two Grounded Capacitors

Dual-Mode Single-Input Three-Output Multifunction Filter and Quadrature Oscillator Consisting of Two Voltage Differencing Transconductance Amplifiers and Two Grounded Capacitors

Linear Voltage Controlled Oscillator Implementation in Electronically Variable Immittances

New realization schemes of electronically tunable inductor (L) and Frequency-Dependent Negative Resistance (D) type immittances using a Current Feedback Amplifier (CFA) and Multiplication Mode Current Conveyor (MMCC) composite active building block (ABB) are proposed. Applications of the immittances to the design of selective filters and LC-type linear voltage controlled quadrature oscillator (LVCQO) are presented. Experimental results based on PSPICE simulation and hardware design for a linear range of oscillation frequency (fo ~ 13.6MHz) with satisfactory phase-noise figure on the oscillator wave response had been verified. Effects of the Active Building Block (ABB)-nodal imperfections are analyzed to be insignificant. The new ideas in this article are two types of immittance functions realizable in the same topology; appropriate frequency-domain selective responses are also presented with experimentation results.

Experimental Verification of On-Chip Biquadratic Filter and Oscillator

This article presents an improved gain-independent tunable voltage-mode (VM) multifunction biquadratic filter (MBF) based on the current-feedback amplifier (CFA), which is easily modified as a quadrature oscillator (QO). Each of the proposed VM-MBF and VM-QO configurations is implemented on a chip employing Taiwan Semiconductor Manufacturing Company (TSMC) <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$0.18~\mu \text{m}$ </tex-math></inline-formula> process with three CFAs, two grounded capacitors, and five resistors. The proposed VM-MBF and VM-QO configurations are both implemented on integrated circuits (ICs) with chip areas of 0.24 and 0.23 mm2 (without PADs), respectively. Based on a ±0.9 V voltage supply and a rail-to-rail input voltage range of 0.05 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\text{V}_{\text {pp}} \le {V}_{\text {in}} \le {1.5}~\text{V}_{\text {pp}}$ </tex-math></inline-formula> , the VM-MBF chip has a maximum efficiency of 83.33%. For linear evaluation of the VM-MBF chip, the measured input 1-dB compression point (P1dB) is about 8.1 dBm. For nonlinear evaluation of the two-tone test, the measured third-order intercept point (TOI) and third-order intermodulation distortion (IMD3) are about 27.26 dBm and −67.5 dBc, respectively. The measured phase noise (PN) of the VM-MBF chip is −101.06 dBc/Hz at 1 kHz offset. With high-input (HI) and low-output (LO) impedances, the proposed VM-MBF can simultaneously achieve inverting low-pass (ILP), inverting bandpass (IBP), and non-inverting band-stop (NBS) responses with gain-independent controllability. It can be easily modified into a VM-QO with fully decoupled control of both the frequency of oscillation (FO) and condition of oscillation (CO). The simulation and measurement results in the time and frequency domains confirm the theories of the proposed VM-MBF and VM-QO configurations.

Third‐order quadrature sinusoidal oscillators with fully uncoupled tuning laws using only two CFOAs and grounded capacitors

SummaryRecently, three current feedback operational amplifiers (CFOA)‐based third‐order quadrature sinusoidal oscillators (TOQSO) have been presented whose condition of oscillation (CO) and frequency of oscillation (FO) can be regulated independently. In this communication, we present two new TOQSO circuits, which require only two CFOAs and yet achieve as significant features as the quoted circuits, namely, the availability of fully uncoupled control of CO and FO, availability of both outputs from ideally zero output impedance nodes (which is beneficial for easy cascadability in VM operations) and employment of all (three) grounded capacitors as preferred for IC implementation. The verification of the workability of proposed circuits has been carried out experimentally using commercially available off‐the‐shelf ICs AD844‐type CFOAs, and some experimental results have been appended.

CFOA-based first-order voltage-mode universal filters

In this paper, two new CFOA-based first-order voltage-mode universal filters are proposed. Both of the filters use an additional unity gain-inverting amplifier. The first proposed filter employs a minimum number of passive elements, while the second one includes one capacitor and two grounded resistors. The proposed filters can give universal filter responses with the selection of their relevant inputs. Both of the proposed filters enjoy the low output and high input impedances. Two quadrature oscillator circuits derived from the proposed filters are also considered as application examples. In order to see the performance of the circuits, many simulations are carried out via the SPICE program. Also, some experiments for the first proposed filter are done by using AD844s.

0.5 V Versatile Voltage- and Transconductance-Mode Analog Filter Using Differential Difference Transconductance Amplifier

In this work, a new versatile voltage- and transconductance-mode analog filter is proposed. The filter, without requiring resistors, employs three differential-difference transconductance amplifiers (DDTAs) and two grounded capacitors, which is suitable for integrated circuit implementation. Unlike previous works, the proposed filter topology provides: (1) high-input and low-output impedances for a voltage-mode (VM) analog filter, that is desirable in a cascade method of realizing higher order filters, and (2) high-input and high-output impedances for a transconductance-mode (TM) analog filter without any circuit modification. Moreover, a quadrature oscillator is obtained by simply adding a feedback connection. Both VM and TM filters provide five standard filtering responses such as low-pass, high-pass, band-pass, band-stop and all-pass responses into single topology. The natural frequency and the condition of oscillation can be electronically controlled. The circuit operates with 0.5 V supply voltage. It was designed and simulated in the Cadence program using 0.18 µm CMOS technology from TSMC.

Reconfigurable Voltage-Mode First-Order Multifunction Filter Employing Second-Generation Voltage Conveyor (VCII) With Complete Standard Functions and Electronically Controllable Modification

In this contribution, the realization of a first-order, two-input, single-output voltage-mode multifunction filter employing a second-generation voltage conveyor (VCII) is described. The proposed first-order versatile filter is extremely simple, composed of a single VCII and three passive devices. Because of its low output impedance, the output voltage node can be easily cascaded with other voltage-mode configurations without the requirement of any buffers. In the same circuit topology, the proposed first-order filter provides various filtering functions: inverting and non-inverting low-pass (LPF), inverting and non-inverting high-pass (HPF), as well as inverting and non-inverting all-pass (APF). The digital method allows the selection of output first-order filtering functions without the need for additional circuits such as inverting or double-gain amplifiers. Furthermore, the pass-band gain of the low-pass and high-pass responses can be adjusted by varying the resistance or capacitance values without influencing the pole frequency as well as the phase response. The influence of VCII’s current/voltage gain errors and parasitic elements on filtering performance is also investigated. Moreover, the modification of the proposed lagging phase all-pass filter to achieve electronic controllability is also proposed by replacing the passive resistor with the operational transconductance amplifier (OTA). The <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$0.18\mu \text{m}$ </tex-math></inline-formula> TSMC CMOS structure of the VCII employed in the proposed filter operates in the subthreshold region and utilizes the bulk-driven technique (BD), enabling it to operate with 0.4V supply voltage and consuming 383 nW of power. The total harmonic distortion (THD) of the LPF with an applied input voltage <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$V_{inpp}=300$ </tex-math></inline-formula> mV @ 50Hz is -49.5 dB. An application example as a quadrature sinusoidal oscillator realized from the proposed first-order allpass filter and lossless integrator is also included. The performance of the proposed reconfigurable voltage-mode first-order filter is simulated and experimentally tested using a commercially available AD844 IC-based VCII with ±5 V power supply.

Arbitrarily Tunable Phase Shift in Low-Frequency Multiphase Oscillator

A special electronically tunable multiphase oscillator with arbitrarily and continuously adjustable phase shifts is introduced. Our design assumes to set the phase around the asymptotical limit of 180°. These features cannot be easily achieved by a standard way, i.e., any simple single-phase oscillator supplemented by a first-order adjustable all-pass section (shifter). The proposed design uses an electronically linearly tunable quadrature oscillator with frequency range from 0.98 up to 12.54 kHz. It also offers multiples of 45° as the initial setting of the phase shift tuning region. The example of operation shows the adjustment of the phase shift at a specific frequency (10 kHz) within the range of ±45° and around -180°, -135° and -90°. This variability is not available in standard cases without the use of several all-pass sections. The current value of the phase shift of the presented oscillator is electronically controlled and does not influence the oscillation frequency and condition of oscillation. Output levels of produced signals are not influenced by this tuning process and are in the range of several hundred mV. Two applications of the oscillator are proposed. The first one focuses on low-bitrate modulation systems (phase shift keying) while in the second one our circuit represents a source of phase-adjustable signals in acoustic experiments. Discrete passive elements and active devices (special multipliers having current output terminals, unity-gain differential voltage buffers) fabricated in 0.35 μm I3T25 ON Semiconductor 3.3 V CMOS process are used in experimental verification.

Third-Order Quadrature Oscillator With Arbitrary Phase Shift Generation and Amplitude Modulation Using MDXCCCTA

Third-Order Quadrature Oscillator With Arbitrary Phase Shift Generation and Amplitude Modulation Using MDXCCCTA

0.5 V Universal Filter and Quadrature Oscillator Based on Multiple-Input DDTA

This paper presents a universal voltage-mode filter and quadrature oscillator based on low-voltage multiple-input differential difference transconductance amplifier (MI-DDTA). Unlike the previous published DDTAs, that utilize the bulk-driven (BD) multiple-input MOS transistor technique (MI-MOST) in the differential pair of the first stage only, the proposed DDTA, for the first time, utilize the BD MI-MOST in the second stage of the DDTA. This results in capability of providing more arithmetic operations without additional current branches or power dissipation. Hence, simplify the topology of the filter and oscillator applications, by decreasing the count of active blocks. The voltage-mode filter offers high-input and low-output impedances, and both non-inverting and inverting versions of five types of transfer functions, namely low-pass, high-pass, band-pass, band-stop, and all-pass characteristics. The oscillator offers three-phase of quadrature signals, and orthogonal control of the condition and frequency of oscillations. The circuit was designed in Cadence environment using 180 nm CMOS TSMC technology. The voltage supply is 0.5 V and the power consumption of the filter is 472 nW. The simulation results are in accordance with theory and confirm the performance of the proposed circuit.

Tek CDBA Tabanlı Çok İşlevli Filtre Tasarımı

In this study, we proposed a second-order multifunction filter topology based on a current differencing buffered amplifier. With the proposed topology, five filter functions can be realized. Sensitivity and non-ideal state analyses of the proposed circuit have been performed. In addition to the proposed second-order multifunction filter topology, the third-order quadrature oscillator circuit was operated as the application circuit. In both circuits, the theoretical work and simulation results are in compliance. The proposed design has potential in the medical device design field.

VDTA-based floating/grounded series/parallel R-L and R-C immittance simulators with a single grounded capacitor

Active configurations for simulating floating/grounded series and parallel immittance functions based on voltage differencing transconductance amplifiers (VDTAs) are proposed. The grounded series and parallel immittance simulators presented here require only one VDTA, while the proposed floating ones only need two. Each of the suggested simulators uses a single grounded capacitor. The proposed topologies can imitate R-L and R-C immittances in both series and parallel types. All of the simulated equivalent elements are electronically adjustable through the VDTA’s transconductance. Furthermore, no component-matching restrictions are imposed in order to achieve the appropriate immittance function. Applications of the proposed VDTA-based immittance simulators include bandpass filter and quadrature oscillator implementations. The behaviors of the proposed circuits and their applications are evaluated by PSPICE simulations and experimental observations using VDTA implemented with commercially available CA3080 type OTAs.

Differential Input First-Order Universal Filter with Two DVCC+s

In this paper, a differential-input plus-type differential voltage current conveyor-based first-order universal filter is designed. This voltage-mode filter uses a grounded capacitor. In addition, it can provide all the noninverting and inverting first-order universal filter responses. The circuit provides high common-mode rejection ratio of about 76.5 dB. Nevertheless, it needs a single matching problem and comprises two floating resistors. Quadrature oscillator (QO) design is obtained using this filter as an application example. The designed filter and QO circuits are simulated through the SPICE program, and some experimental studies are carried out using AD844 ICs to verify the theory.

Two New Voltage-Mode Sinusoidal Quadrature Oscillators Employing Second-Generation Voltage Conveyors

This article presents an application of a second-generation voltage conveyor (VCII) as a quadrature oscillator. The controlling parameters of the presented circuits, i.e. oscillation condition and oscillation frequency are tuneable without affecting the other. Both the single-resistance-controlled oscillators employ only two VCII, two grounded capacitors, and three grounded/ virtually grounded resistors. To strengthen the design idea regular mathematical analysis such as ideal, non-ideal, parasitic, frequency stability, phase noise analysis, and sensitivity calculations have been performed. To validate the proposed networks, the simulations have been carried out using 180 nm CMOS technology parameters, and experimental studies have also been performed using commercially available integrated circuits.

New Voltage-Variable Immittance Functions: Linear Voltage-Controlled Quadrature Oscillator

A new voltage-variable immittance functions (VVIFs) implementation has been proposed. Here two types of grounded-immittances function have been realized viz., inductor (L) and Frequency-Dependent Negative Resistor (D) using a pair of ABBs i.e. Current Feedback Amplifier (CFA-AD844) amalgamated with analog voltage-multiplier (AD-835) devices. Thereafter, high-quality (Q) resonant filters and voltage-controlled quadrature oscillator (VCQO) implementation with linear tuning law are designed using the proposed VVIF. The analysis indicates that the filter/oscillator parameters are impervious to the effects of the CFA-device parasitic capacitors. A VCQO-linear tuning range of f o∼14 MHz with a satisfactory phase-noise margin of (–)103 dBc/Hz at 29 KHz for the LC-type linear QO has been experimentally observed.

1.2 V differential difference current conveyor using MIGD MOST technique and its applications

This paper presents a new differential difference current conveyor (DDCC), realized using multiple-input gate-driven MOS transistor (MIGD MOST) technique. The application of MIGD MOST can reduce the number of differential pairs in the input stage of the DDCC, thus simplifying its overall structure. Unlike previous DDCC, the output stage of the circuit operates in super class-AB, that offers low static power consumption, high load driving capability and improved gain-bandwidth product (GBW).The proposed DDCC can work with the supply voltage of 1.2 V and consumes 44.2 μW of power. The proposed DDCC has been used to realize a versatile circuit that can work as a universal filter or a quadrature oscillator into a single topology. When the circuit works as a universal filter, it can realize low-pass, band-pass, high-pass, band-stop and all-pass voltage responses. The natural frequency and the quality factor of these responses can be orthogonally controlled. When the circuit works as a quadrature oscillator, the condition and the frequency of oscillators can be orthogonally controlled. The proposed MIGD DDCC and the proposed universal filter and quadrature oscillator have been simulated with SPICE, using 0.18 μm CMOS process parameters to prove the functionality and workability of the new circuits.

Resistor-Less Capacitor-Controlled Single VDIBA-Based Third-Order Quadrature Sinusoidal Oscillator

This paper presents a new voltage-mode (VM) third-order quadrature sinusoidal oscillator (TOQSO) employing a single voltage differencing inverting buffered amplifier (VDIBA) along with three grounded capacitors (GCs) (suitable for IC implementation and also for parasitic absorption) and two NMOS transistors (operated in triode region). The condition of oscillation (CO) and frequency of oscillation (FO) of the presented circuit are self-regulating, i.e. CO can be regulated electronically by transconductance and by varying capacitors, and the FO can be tuned. Non-ideal analysis of the presented TOQSO circuit has been carried out and the results have been compared with ideal ones. Sensitivities of FO with respect to active and passive components have been evaluated and found to be less and also the presented oscillator configuration has low power dissipation and low total harmonic distortions (THD). The feasibility of the presented circuit has been validated using high-performance tunable CMOS VDIBA with a low supply voltage ±0.6 V. Experimental results have also been corroborated using VDIBA, implemented with commercially available ICs MAX435 and AD830.