VDTA Based Electronically Tunable Voltage-Mode and Trans-Admittance Biquad Filter

Abstract

In this paper, a biquad filter configuration based on two voltage differencing transconductance amplifiers (VDTAs) as newly active elements and only two capacitors as passive elements is proposed which can realize voltage-mode low pass (LP), band pass (BP), high pass (HP), band reject (BR) and all pass (AP) filtering responses using three voltage inputs. Simultaneously, the same configuration can also be used to obtain LP, BP and HP filtering responses in transadmittancemode. The proposed biquad is capable of providing electronic control of quality factor independent of pole frequency through single transconductance parameter (biasing current). It also offers the advantage of low active and passive sensitivity. To support the theoretical analysis, the PSPICE simulation of the proposed circuit is done using 0.18 μm CMOS technology from TSMC.

A Novel Simple Differentiator Circuit Based on Carbon Nano Tube Field Effect Transistors Voltage Difference Transconductance Amplifier

“…In view of carrying such specific properties, the VDTA has been treated as the most favored element in use for various applications. Some of the applications include filters, oscillators, simulation of inductors and capacitors which use one VDTA block taking the help of capacitors [22][23][24][25][26][27][28][29][30][31][32][33]. Some of the current mode devices are furnished below.…”

High‐Q second‐order all‐pass delay network in CMOS

“…In this paper, we choose f 0 = 200 MHz and Δτ = 7 ns. Component values are then calculated using (10), with α chosen as 10 −3 . Using the means A v and A i from Table 3, the synthesis results in R 1 = 1074 Ω, R 2 = 1 kΩ, R 3 = 470 Ω, R 4 = 695 Ω, C 1 = 0.74 pF, C 2 = 0.80 pF, C 3 = 1.69 pF, and C 4 = 1.15 pF.…”

“…In [28,30,31], a special case of a second-order delay network is obtained with the resonant frequency at 0 Hz, and therefore a Q D -value of 0. To avoid an approximation to an ideal second-order all-pass response and to increase the achievable Q D -value, operational amplifier and second-generation current conveyor (CCII)-based realisations have been proposed [8][9][10][11][12][13][14][15][16][17][18][19][20][21][22] which can potentially achieve Q D -values larger than 1. Op-amp-based realisations are generally undesirable due to low bandwidths [9], sparking interest in CCII-based implementations.…”

“…Op-amp-based realisations are generally undesirable due to low bandwidths [9], sparking interest in CCII-based implementations. These devices exhibit higher bandwidth, greater linearity and lower-power consumption than op-amps, making them better suited for implementation of second-order all-pass networks [8][9][10][11][12][13][14][15][16][17][18][19][20][21][22]. However, CCII non-idealities such as non-unity voltage mirroring (A v ) and current conveying (A i ), non-zero input resistance at port X (R X ), and finite values of output resistance at ports Y and Z (R Y and R Z ) make many of these designs impractical, even when using high-precision CCIIs [33].…”

Electronically tunable current mode biquad filter based on single VDTA and grounded passive elements

“…VDTA DESCRIPTION The VDTA is relatively new element and has been popularized and frequently used in designing of analog filters [10,13,22,[26][27][28][29] in last few years. The symbolic diagram of VDTA is shown in Fig.1.…”