Electronically Tunable Voltage-Mode Multiphase Sinusoidal Oscillator with Low Output Impedance Nodes Employing VD-DIBAs

The multiphase sinusoidal oscillator (MSO) is useful for various electrical and electronic applications. This study aims to design an MSO employing voltage differencing differential input buffered amplifiers (VD-DIBAs). The design procedure is based on cascading the first-order low-pass filter. Each phase consists of a VD-DIBA, two resistors, and a grounded capacitor. An odd-phase system without requiring an additional amplifier. The frequency is electronically controlled through the bias current without affecting the condition. The sinewave amplitudes and the phase difference between each waveform are identical. The proposed MSO is designed to obtain three-phase waveforms (n = 3). PSPICE simulation demonstrates the performance of the proposed oscillator with 0.18 μm TSMC CMOS parameters with ±0.9 V power supply. The feasibility of the proposed MSO is also verified with experiments using the VD-DIBA constructed from commercial integrated circuits (ICs) with a ±5 V power supply. The simulated and experimental results align with theoretical predictions

Three-Input Single-Output Voltage-Mode Multifunction Filter with Electronic Controllability Based on Single Commercially Available IC

This paper presents a second-order voltage-mode filter with three inputs and single-output voltage using single commercially available IC, one resistor, and two capacitors. The used commercially available IC, called LT1228, is manufactured by Linear Technology Corporation. The proposed filter is based on parallel RLC circuit. The filter provides five output filter responses, namely, band-pass (BP), band-reject (BR), low-pass (LP), high-pass (HP), and all-pass (AP) functions. The selection of each filter response can be done without the requirement of active and passive component matching condition. Furthermore, the natural frequency and quality factor are electronically controlled. Besides, the nonideal case is also investigated. The output voltage node exhibits low impedance. The experimental results can validate the theoretical analyses

A voltage-mode first order allpass filter based on VDTA

This article presents a new voltage-mode first order allpass filter (APF) employing voltage differencing transconductance amplifier (VDTA). The advantages of the circuit are that: the circuit description is very compact, consists of merely a VDTA and a capacitor: the phase shift can be electronically adjusted by current bias: it provides the lower THD of the output signal. Without any component matching conditions, the proposed circuit is very appropriate to further develop into an integrated circuit. Moreover, the proposed APF can provide the output current with high output impedance without modification of the circuit topology. The PSpice simulation results are depicted. The given results agree well with the theoretical anticipation. The maximum power consumption is 400µW at ±1.25V power supplies

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 in a standard way, i.e., any simple single-phase oscillator supplemented by a first-order adjustable all-pass (AP) section (shifter). The proposed design uses an electronically linearly tunable quadrature oscillator with a 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 degrees. and around -180 degrees, -135 degrees, and -90 degrees. This variability is not available in standard cases without the use of several AP 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 hundreds of mV. Two applications of the oscillator are proposed. The first one focuses on low-bitrate modulation systems [phase shift keying (PSK)] 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 mu m I3T25 ON Semiconductor 3.3 V CMOS process are used in experimental verification

One input voltage and three output voltage universal biquad filters with orthogonal tune of frequency and bandwidth

This research paper contributes the one input three output voltage mode universal biquad filters with linear and electronic control of the natural frequency (w0), using two commercially available ICs, LT1228s as active device with two grounded capacitors, five resistors. The presented universal biquad filters can simultaneously provide three voltage-mode filtering functions, low-pass (LP), high-pass (HP) and band-pass (BP) without changing the circuit architecture. Furthermore, the first presented biquad filter provides low impedance at HP, BP voltage output nodes and LP, BP output voltage nodes are low impedance for the second proposed filter which is easy cascade ability with other voltage mode circuits without the employment of buffer circuits. The quality factor (Q) of both proposed filters is orthogonally adjusted from the passband voltage gain and w0. The proposed filters are simulated and experimented with commercially accessible ICs, LT1228. The simulated and experimental results demonstrate the filtering performances

High input impedance voltage-mode universal filter and its modification as quadrature oscillator using VDDDAs

The second order universal voltage-mode filter using voltage differencing differential difference amplifiers (VDDDAs) has been proposed. It has high input impedance voltage-mode biquad filter with orthogonal tune of natural frequency and quality factor. The proposed filter simultaneously provides five filter responses: low-pass (LP), high-pass (HP), band-reject (BR), all-pass (AP) and band-pass (BP) in the same circuit topology. The natural frequency and quality factor can be tuned electronically and orthogonally dc bias current. The output impedance at output nodes HP, AP and BR has low impedance which can connect to other circuit without the use of voltage buffers. The proposed filter consists of three VDDDAs, one grounded resistor and two grounded capacitors. This makes the proposed filter suitable for integrated circuit development. With slightly modifying the proposed filter, the voltage-mode qudrature sinusoidal oscillator with low output impedance and independent control of condition of oscillation (CO) and frequency of oscillation (FO) has been achieved. The results shown in this paper are from PSPICE simulation and experiment to validate the proposed circuits

Electronically and Independently Controllable Quadrature Sinusoidal Oscillator with Low Output Impedances

This work presents the quadrature si- nusoidal oscillator using two Voltage Differencing- Differential Input Buffered Amplifiers (VD-DIBAs), two resistors, and two capacitors. The VD-DIBA is an electronically controllable active building block with high input and low output impedances that can con- nect to other circuits directly without the buffers. With these distinguished features, the VD-DIBA is employed in this design. The proposed oscillator can produce two sine waves with a phase shift of 90 degrees. Over the entire tuning frequency range, the magnitude of the quadrature output voltages is constant. The pro- posed oscillator is independently adjustable in terms of frequency and oscillation condition. Moreover, the frequency of oscillation can be electronically and lin- early adjusted by the bias currents. The condition of oscillation is adjustable by resistors, R1 and R2. The performances of the proposed quadrature oscilla- tor are tested through the PSpice simulation and the experiment. In the simulation, the VD-DIBA is built from the 0.18 μm Taiwan Semiconductor Manufactur- ing Company (TSMC) CMOS process with ±0.9 V sup- ply voltages. In the experiment, the VD-DIBA is im- plemented using the commercial ICs, LM13700, and AD830 with ±5 V supply voltages. The simulated To- tal Harmonic Distortion (THD) values of the output voltages, Vo1 and Vo2 at f0 = 1.03 MHz are 1.63 % and 1.81 %, respectively. The experimental THD values of the output voltages, Vo1 and Vo2 at f0 = 536.6 kHz, are 1.43 % and 1.00 %, respectively

Readout for simple and precise analog acoustic impact initialization

An economic concept of acoustic shock wave sensing readout system for simple computer processing is introduced in this work. Its application can be found in precise initialization of the stopwatch from the starter sound, handclap or gun in competitive sport races but also in many other places. The proposed device consists of several low-cost commercially available components and it is powered by a 9 V battery. The proposed device reliably reacts on incoming acoustic shock wave by generation of explicit impulse having controllable duration. It significantly overcomes basic implementations using only a microphone and amplifier (generating parasitic burst instead of defined and distinct impulse) or systems allowing a limited number of adjustable features (gain and/or threshold of the comparator-our concept offers the adjustment of gain, cut-off frequency, threshold level and time duration of active state). In comparison with standard methods, the proposed approach simplifies and makes sensing device less expensive and universal for any powder-based starting gun (without necessity to adapt starting gun). The proposed device, among others, has the following features: impulse duration can be controlled from hundreds of mu s up to 2.3 s, the gain range of linear part of processing from 6 to 40 dB and open-collector output compatible with 5 V TTL or 3.3 V CMOS logic. The initialization has been tested in the range from tens of centimeters up to four meters. In order to highlight the important spectral components, the spectral character of the signal can be optimally reduced by a low-pass filter. The quiescent power consumption of the designed simple analog circuit reaches 90 mW. Several use cases, response of the designed system on gunshot signature, talking, hand-clapping and hit on the sensing microphone, are studied and compared to each other. Simulation and experimental results confirm functionality of the realized system

Realization of electronically tunable voltage-mode/current-mode quadrature sinusoidal oscillator using ZC-CG-CDBA

a b s t r a c t This paper presents a first of its kind canonic realization of active RC (ARC) sinusoidal oscillator with non-interactive/independent tuning laws, which simultaneously provides buffered quadrature voltage outputs and explicit quadrature current outputs. The proposed circuit is created using a new active building block, namely the Z-copy controlled-gain current differencing buffered amplifier (ZC-CG-CDBA). The circuit uses three resistors and two grounded capacitors, and provides independent/non-interactive control of the condition of oscillation (CO) and the frequency of oscillation (FO) by means of different resistors. Other advantageous features of the circuit are the inherent electronic tunability of the FO via controlling current gains of the active elements and the suitability to be employed as a low-frequency oscillator. A non-ideal analysis of the circuit is carried out and experimental results verifying the workability of the proposed circuit are included