Panit Lamun

Current‐mode quadrature oscillator using current differencing transconductance amplifiers

This article presents a new electronically tunable single‐element‐controlled current‐mode quadrature sinusoidal oscillator circuit using current differencing transconductance amplifiers (CDTAs). The proposed oscillator is consisted of two CDTAs, two grounded capacitors and one grounded resistor, which is beneficial to monolithic integrated circuit implementation both in CMOS and bipolar technologies. The condition of oscillation and the frequency of oscillation are independently controllable. The frequency of oscillation can also be electronically controlled by adjusting the bias current of CDTA. The circuit provides four quadrature current outputs and two quadrature voltage outputs. The current output terminals possess high impedance level. PSPICE simulation results are used to verify the performance of the proposed circuit implemented at the transistor level. The measurement results support the computer simulations.

Current-mode third-order quadrature oscillator using VDTAs and grounded capacitors

This paper presents a novel electronically tunable current-mode third-order quadrature oscillator based on voltage differencing transconductance amplifier (VDTA). The proposed oscillator is constructed using two VDTAs and three grounded capacitors, which is advantageous for integrated circuit implementation. The circuit provides two current outputs with 90° phase difference from high output impedance terminals. The condition of oscillation and the frequency of oscillation can be electronically tuned by adjusting the bias current of the VDTAs. The sensitivity studies of the circuit have been carried out. PSPICE simulations with 0.35 μm TSMC CMOS process parameters are given to confirm the theoretical analysis.

A new mixed-mode quadrature oscillator using a single CCCDTA

This paper presents a new current-controlled mixed-mode quadrature oscillator using only a current controlled current differencing transconductance amplifier (CCCDTA), two grounded capacitors and one MOS resistor. The structure is beneficial to monolithic integrated circuit implementation. The proposed circuit provides two quadrature voltage outputs and two quadrature current outputs. The quadrature current outputs also offer the feature of high output impedance. The oscillation condition and the oscillation frequency of the oscillator are independently controllable. PSPICE simulation results which confirm the theoretical predictions are also given.

A Voltage-Mode Universal Biquadratic Filter Using DDCCTA

This paper presents a new voltage-mode (VM) universal biquadratic filter using differential difference current conveyor transconductance amplifier (DDCCTA) as an active element. The circuit employs one DDCCTA, two floating resistors and two floating capacitors which can realize five biquadratic filters, namely low-pass (LP), band-pass (BP), band-stop (BS), high-pass (HP) and all-pass (AP) into one single topology. For realizing these filtering functions, passive component-matching conditions, inverting-type and/or doubling-input signal requirements and changing circuit configuration are absent. The natural angular frequency and quality factor of the filter can be orthogonally controlled deliberately. The VM biquadratic filter using grounded passive components with high-input and low-output impedances can be obtained by adding an additional DDCCTA or differential difference current conveyor (DDCC). The simulation results with 0.5μm CMOS process from MIETEC are given to confirm the theoretical predictions and the experimental results are also included to verify the workability of the proposed structure.

Tunable Current-Mode Quadrature Sinusoidal Oscillator Using CCCFTAs and Grounded Capacitors

This paper presents a new electronically tunable current-mode quadrature sinusoidal oscillator which employs only two current-controlled current follower transconductance amplifiers (CCCFTAs) and two grounded capacitors. The proposed oscillator offers the advantages of independent electronic control for setting the frequency of oscillation and the condition of oscillation, availability of two explicit quadrature current outputs, and low active and passive sensitivities. The outputs of the circuit possess high impedance level which is directly connected to the loads without buffer circuits. The use of grounded capacitors makes the proposed structure highly suitable for integrated circuit implementation. The workability of the proposed structure is verified by PSPICE simulations based on CMOS technology.

Current-mode quadrature oscillator using minimum elements

This paper presents a new current-mode quadrature oscillator employing only a single current-controlled current conveyor transconductance amplifier, two grounded capacitors and one grounded resistor. The circuit is beneficial to monolithic integrated circuit implementation by using grounded capacitors. The oscillation condition and the oscillation frequency can be independently controlled. The oscillation frequency can also be controlled electronically by adjusting the bias currents. The realized of the circuit provides explicit quadrature voltage and current outputs. Simulation results that confirm the theoretical predictions are also given.

Allpass section-based mixed-mode quadrature sinusoidal oscillator

This paper presents a new electronically tunable mixed-mode quadrature sinusoidal oscillator using new allpass section as an building block. The oscillator is consisted of two allpass sections. Each allpass section employs one current-controlled current differencing transconductance amplifier and one grounded capacitor. The condition of oscillation and the frequency of oscillation can be controlled independently and electronically by adjusting the bias currents. The oscillator also offers two explicit quadrature voltage and quadrature current outputs into a single topology. The workability of the proposed structure is verified by PSPICE simulators based on 0.25 μm TSMC CMOS process.

Voltage-mode universal biquadratic filter using a single DDCCTA

In this paper, a novel two-input four-output voltage-mode universal biquadratic filter is presented. The filter circuit uses only one differential difference current conveyor trans-conductance amplifier (DDCCTA) and four passive components. The circuit can provide low-pass (LP), band-pass (BP), band-stop (BS), high-pass (HP), and all-pass (AP) biquadratic functions. The natural angular frequency (ωo) and the quality factor (Q) can be orthogonally tuned by adjusting the circuit components. The proposed configuration has a low component count and low active and passive sensitivities. PSPICE simulations with 0.5 μm MIETEC CMOS process parameters are given to confirm the theoretical predictions.

Single VDCC-based current-mode universal biquadratic filter

This paper presents a novel three-input single-output current-mode universal biquadratic filter using only one voltage differencing current conveyor (VDCC) and three grounded passive components. The proposed circuit can realize low-pass (LP), band-pass (BP), high-pass (HP), band-stop (BS), and all-pass (AP) biquadratic functions. The natural angular frequency (ωo) and the quality factor (Q) can be tuned orthogonally by varying the circuit components. The proposed configuration has a low component count, low active and passive sensitivities and suitability to be integrated circuit implementation. PSPICE simulation results using TSMC 0.18 μm CMOS process parameters are included, which show good agreement with the theoretical predictions.

Mixed-mode quadrature oscillator using a single DDCCTA and grounded passive components

A new mixed-mode quadrature oscillator using a single differential difference current conveyor transconductance amplifier (DDCCTA), two grounded resistors, and two grounded capacitors is presented. The proposed circuit provides both quadrature voltage and quadrature current outputs simultaneously. The condition of oscillation (CO) and frequency of oscillation (FO) of the circuit are orthogonally controllable. The circuit is beneficial to monolithic integrated circuit implementation by using all grounded passive components. Moreover, the active and passive sensitivities of the proposed configuration are low. The validity of the proposed oscillator has been established by PSPICE simulations using MIETEC 0.5 μm CMOS technology.