Electronically and Orthogonally Tunable SITO Voltage-Mode Multifunction Biquad Filter Using LT1228s

The commercially available IC LT1228 is an interesting active device due to its advantage features, such as a fast transconductance amplifier, a wide bandwidth over a wide range of voltage gain, low total harmonic distortion (THD), high impedance differential input, etc. The single-input triple-output (SITO) voltage-mode (VM) multifunction biquadratic filters using ICs, LT1228s are introduced in this research. This circuit design provides the three-filtering functions, low-pass (LP), high-pass (HP), and band-pass (BP), without changing the circuit architecture. It comprises three LT1228s, four resistors, and two capacitors connected to the ground. The low impedance voltage output nodes are HP and BP responses. The quality factor (Q) and the pole frequency (ω0) can be electronically and orthogonally tuned by altering the third LT1228’s bias current (IB). The PSPICE simulation and the experiment are verified to describe the circuit operation.

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 (<em>w₀</em>), 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 (<em>Q</em>) of both proposed filters is orthogonally adjusted from the passband voltage gain and <em>w₀</em>. The proposed filters are simulated and experimented with commercially accessible ICs, LT1228. The simulated and experimental results demonstrate the filtering performances.

CMOS Realization of Fully Electronically Tunable Single Resistance Control Mixed Mode Biquad Filter Employing Single VDTA at ± 0.6V

This paper presents a single resistance control single VDTA based Mixed Mode type Biquad filter. The proposed Transadmittance Mode (TAM) type Biquad filter configuration employed single voltage differencing transconductance amplifier (VDTA) as an active building block, three passive element namely one grounded resistor, one grounded capacitor and one floating capacitor. The proposed transadmittance Mode multifunction Biquad filter configuration is presenting transadmittance mode type four basic standard filter functions low pass, high pass, band pass, band reject or band stop or band eliminate filter responses. These four type filter responses are realizing simultaneously with the selection of single input voltage signal. The proposed Transadmittance Mode multifunction Biquad filter configuration has more advantageous features such as low active and passive sensitivities, low power supply voltage, low power consumption, low quality factor, very low power consumption, more electronic tunability, higher linearity and required small area of the chip. The performance of the proposed configuration has been verified through PSPICE simulation using 0.18μm CMOS Technology process parameters.

High-Input Impedance Voltage-Mode Multifunction Filter

This paper proposes a high-input impedance voltage-mode (VM) multifunction biquad filter which employs three current-feedback amplifiers (CFAs), three resistors, and two grounded capacitors. The proposed VM multifunction biquad filter has single-input and triple-output and can realize non-inverting low-pass (NLP), inverting band-pass (IBP), and non-inverting band-stop (NBS) voltage responses at the same time without increasing component selection. The proposed VM multifunction biquad filter enjoys the orthogonal tunability of angular frequency and quality factor and also provides the advantage of using only two grounded capacitors, high-input impedance and low active/passive sensitivity. The performance of the proposed VM multifunction biquad filter is verified through its hardware implementation and OrCAD PSpice simulation based on AD844-type CFAs. The circuit analysis, sensitivity analysis, and NLP, IBP, and NBS voltage responses are also shown in this paper. The paper presents a method to effectively reduce the active and passive components, maintain good circuit performance, and reduce circuit costs.

Dual-mode multifunction filter realized with a single voltage differencing gain amplifier (VDGA)

This article presents the dual-mode multifunction biquad filter realized employing only a single voltage differencing gain amplifier (VDGA), one resistor and three capacitors. The proposed filterwith one input and three outputs can configure as voltage-mode or current-mode filter circuit with the appropriate input injection choice. It can also synthesis the three standard filter functions, which are highpass, bandpass, and lowpass responses without modifying the circuit configuration. Orthogonal adjustment between the natural angular frequency (o) and the quality factor (Q) of the filter is achieved. Detail analysis of non-ideal VDGA effects and circuit component sensitivity are included. The circuit principle is verified by means of simulation results with TSMC 0.35-m CMOS process parameters.

CFA BASED UNIVERSAL BIQUAD FILTER

This paper is a review of the organizational structure and challenges that a technological enterprise faces during scaling, from the perspective of the engineering management. After expanding operations internationally, the distributed engineering teams developing hardware and software for internet of things applications, face issues regarding culture, communication, leadership, project planning and management. Relevant literature addressing these issues is presented. We elaborate on already implemented measures for improving the overall efficiency and propose further processes introduced in recent literature that can be beneficial for further optimizing the new product development. Potential knock-on effects by such implementation are also discussed. A universal biquad filter using current feedback amplifiers (CFA) as active devices and a canonical number of capacitors is presented. It realizes the classical feedforward structure through the use of grounded capacitors and MOS transistors, which permit a full integrability. The proposed circuit has attractive characteristics, as the possibility to electronically control the transfer function coefficients and the possibility to be directly inserted within cascaded configurations. The theoretical analysis of the circuit is followed by some PSPICE simulation results in agreement with the theoretical findings. In this paper a universal fully integrable biquad using CFAs as active devices and a canonical number of capacitors is presented. It realizes the classical feedforward structure [3] through the use of grounded capacitors and MOS transistors. The presence of grounded capacitors makes the proposed circuit absorb shunt parasitic capacitances. All the possible kinds of responses can be realized, while in the biquad reported in [2] only the low-pass and band-pass responses can be obtained. The numerator and denominator coefficients of the voltage transfer function of the proposed biquad can be electronically controlled by acting on the gate voltages of the MOS transistors of the circuit. Moreover the presented structure has a low-impedance output and then it can be cascaded without additional buffers.

Voltage-Mode Multifunction Biquad Filter and Its Application as Fully-Uncoupled Quadrature Oscillator Based on Current-Feedback Operational Amplifiers

This research introduces a new multifunction biquad filter based on voltage mode (VM) current-feedback operational amplifier (CFOA) and a fully uncoupled quadrature oscillator (QO) based on the proposed VM multifunction biquad filter. The proposed VM multifunction biquad filter has high impedance to the input voltage signal, and uses three CFOAs as active components, while using four resistors and two grounded capacitors as passive components. The VM CFOA-based multifunction biquad filter realizes band-reject, band-pass, and low-pass transfer functions at high-input impedance node simultaneously, which has the feature of easy cascading in VM operation without the need for additional voltage buffers. Additionally, the filter control factor parameter pole frequency (ωo) and quality factor (Q) of the proposed VM multifunction biquad filter can be independently set by varying different resistors. By slightly modifying the VM multifunction biquad filter topology, a VM fully-uncoupled QO is easily obtained. The difference from the previous VM CFOA-based multifunction biquad filter is that the proposed VM CFOA-based multifunction biquad filter can be independently controlled by the filter control factor parameters, ωo and Q. The proposed VM CFOA-based multifunction biquad filter can be transformed into a VM QO with fully-uncoupled adjustable of the oscillation condition and the oscillation frequency. The oscillation condition and the oscillation frequency can be fully-uncoupled and controlled by varying two sets of completely different resistors. The proposed VM fully-uncoupled QO solves the amplitude instability. The constant amplitude ratio of two quadrature sinusoidal waveforms can be realized when tuning FO. PSpice simulation and experimental results prove the performances of the proposed VM multifunction filter and VM fully-uncoupled QO. Simulation and experimental results confirm the theoretical analysis of the proposed circuits.