The voltage-mode first order universal filter using single voltage differencing differential input buffered amplifier with electronic controllability

In this research contribution, the electronically tunable first-order universal filter employing a single voltage differencing differential input buffered amplifier (VD-DIBA) (constructed from two commercially available integrated circuit (IC): the operational transconductance amplifier, IC number LT1228, and the differential voltage input buffer, IC number AD830), one capacitor and two resistors. The features of the designed first order universal filter are as follows. Three voltage-mode first-order functions, low-pass (LP), all-pass (AP) and high-pass (HP) responses are given. The natural frequency (0) of the presented configuration can be electronically adjusted by setting the DC bias current. Moreover, the voltage gain of the LP and HP filters can be controllable. The phase responses of an AP configuration can be varied from 00 to −1800 and 1800 to 00. The power supply voltages were set at ±5 . Verification of the theoretically described performances of the introduced electronically tunable universal filter was proved by the PSpice simulation and experiment

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

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

Inductance Simulators and Their Application to the 4th Order Elliptic Lowpass Ladder Filter Using CMOS VD-DIBAs

This paper presents inductance simulators using the voltage differencing differential input buffered amplifier (VD-DIBA) as an active building block. Three types of inductance simulators, including floating lossless inductance, series inductance-resistance, and parallel inductance-resistance simulators, are proposed, in addition to their application to the 4th order elliptic lowpass ladder filter. The simple design procedures of these inductance simulators using a circuit block diagram are also given. The proposed inductance simulators employ two VD-DIBAs and two passive elements. The complementary metal oxide semiconductor (CMOS) VD-DIBA used in this design utilizes the multiple-input metal oxide semiconductor (MOS) transistor technique in order to achieve a compact and simple structure with a minimum count of transistors. Thanks to this technique, the VD-DIBA offers high performances compared to the other CMOS structures presented in the literature. The CMOS VD-DIBAs and their applications are designed and simulated in the Cadence environment using a 0.18 mu m CMOS process from Taiwan semiconductor manufacturing company (TSMC). Using a supply voltage of +/- 0.9 V, the linear operation of VD-DIBA is obtained over a differential input range of -0.5 V to 0.5 V. The lowpass (LP) ladder filter realized with the proposed inductance simulators shows a dynamic range (DR) of 80 dB for a total harmonic distortion (THD) of 2% at 1 kHz and a 1.8 V peak-to-peak output. In addition, the experimental results of the floating inductance simulators and their applications are obtained by using VD-DIBA constructed from the available commercial components LM13700 and AD830. The simulation results are in agreement with the experimental ones, confirming the advantages of the inductance simulators and their application

Single Commercially Available IC-Based Electronically Controllable Voltage-Mode First-Order Multifunction Filter with Complete Standard Functions and Low Output Impedance

This paper presents the design of a voltage-mode three-input single-output multifunction first-order filter employing commercially available LT1228 IC for easy verification of the proposed circuit by laboratory measurements. The proposed filter is very simple, consisting of a single LT1228 as an active device with two resistors and one capacitor. The output voltage node is low impedance, resulting in an easy cascade-ability with other voltage-mode configurations. The proposed filter provides four filter responses: low-pass filter (LP), high-pass filter (HP), inverting all-pass filter (AP-), and non-inverting all-pass filter (AP+) in the same circuit configuration. The selection of output filter responses can be conducted without additional inverting or double gains, which is easy to be controlled by the digital method. The control of pole frequency and phase response can be conducted electronically through the bias current (I-B). The matching condition during tuning the phase response with constant voltage gain is not required. Moreover, the pass-band voltage gain of the LP and HP functions can be controlled by adjusting the value of resistors without affecting the pole frequency and phase response. Additionally, the phase responses of the AP filters can be selected as both lagging or leading phase responses. The parasitic effects on the filtering performances were also analyzed and studied. The performances of the proposed filter were simulated and experimented with a & PLUSMN;5 V voltage supply. For the AP+ experimental result, the leading phase response for 1 kHz to 1 MHz frequency changed from 180 to 0 degrees. For the AP- experimental result, the lagging phase response for 1 kHz to 1 MHz frequency changed from 0 to -180 degrees. The design of the quadrature oscillator based on the proposed first-order filter is also included as an application example