High Input Impedance Voltage-Mode Universal Biquadratic Filters With Three Inputs Using Three CCs and Grounding Capacitors

Two current conveyors (CCs) based high input impedance voltage-mode universal biquadratic filters each with three input terminals and one output terminal are presented. The first circuit is composed of three differential voltage current conveyors (DVCCs), two grounded capacitors and four resistors. The second circuit is composed of two DVCCs, one differential difference current conveyor (DDCC), two grounded capacitors and four grounded resistors. The proposed circuits can realize all the standard filter functions, namely, lowpass, bandpass, highpass, notch and allpass filters by the selections of different input voltage terminals. The proposed circuits offer the features of high input impedance, using only grounded capacitors and low active and passive sensitivities. Moreover, the x ports of the DVCCs (or DDCC) in the proposed circuits are connected directly to resistors. This design offers the feature of a direct incorporation of the parasitic resistance at the x terminal of the DVCC (DDCC), Rx, as a part of the main resistance

Tunable Versatile High Input Impedance Voltage-Mode Universal Biquadratic Filter Based on DDCCs

A high input impedance voltage-mode universal biquadratic filter with three input terminals and seven output terminals is presented. The proposed circuit uses three differential difference current conveyors (DDCCs), four resistors and two grounded capacitors. The proposed circuit can realize all the standard filter functions, namely, lowpass, bandpass, highpass, notch and allpass, simultaneously. The proposed circuit offers the features of high input impedance, using only grounded capacitors, and orthogonal controllability of resonance angular frequency and quality factor

Voltage-Mode Highpass, Bandpass, Lowpass and Notch Biquadratic Filters Using Single DDCC

A new voltage-mode multifunction biquadratic filter using one differential difference current conveyor (DDCC), two grounded capacitors and three resistors is presented. The proposed circuit offers the following attractive advantages: realizing highpass, bandpass, lowpass and notch filter functions, simultaneously, from the same circuit configuration; employing grounded capacitors, which is ideal for integration and simpler circuit configuration

New families of voltage-mode and current-mode filter circuits.

In some previous papers, feed forward configurations of realizing second order all pass transfer functions with complex poles by adding some configurations to a first order circuit are discussed. In this dissertation, the above idea extended to realize some other basic second order complex pole filter transfer functions. A new corollary for circuit conversion is proposed and proved. This corollary is useful for converting op amp based voltage-mode circuits to their CCII based equivalent circuits, as are other existing theorems. But the new corollary is useful for converting circuits that cannot be converted by other theorems

Current-mode electronically tunable universal filter using only plus-type current controlled conveyors and grounded capacitors

In this paper we present a new current-mode electronically tunable universal filter using only plus-type current controlled conveyors (CCCII+s) and grounded capacitors. The proposed circuit can simultaneously realize lowpass, bandpass, and highpass filter functions-all at high impedance outputs. The realization of a notch response does not require additional active elements. The circuit enjoys an independent current control of parameters omega(o) and omega(o)/Q. No element matching conditions are imposed. Both its active and passive sensitivities are low

Versatile Active Biquad Using FTFNs

A universal active biquad using the four-terminal floating nullors (FTFNs) is presented. The propsed circuit uses two FTFNs, three capacitors and two resistors. The proposed circuit has three input voltages and can simultaneously provide a high-impedance output current and/or an output voltage. Without changing the circuit topology, the output voltage can realise lowpass, highpass, bandpass, notch and allpass transfer functions and the output current can realise bandpass and highpass transfer functions. The proposed circuit enjoys low active and passive sensitivities and independent control of the parameters ωo and ω0/Q0

Electronically reconfigurable wideband microwave filters

Many systems require multi function capability in the filter aspects of systems; the method currently used is filter banks which take up a lot of board space. It is thought that reconfigurable filters hold the key to replacing filter banks in order to save board space and thus potentially increasing functionality of the systems. The aim of this research is to develop electronically reconfigurable microwave filters for future communication systems. The project investigates some key design issues of reconfigurable filters. Circuits were modelled and full-wave electromagnetic simulations were performed for the investigation. Experimental work was carried out to demonstrate advanced reconfigurable microwave devices. The components used in each concept investigated were pin diodes due to their superior performance in wideband and high frequency applications. Firstly a single coupled line concept was looked at for bandwidth reconfigurability. This concept was then further developed for industrial applications by simply cascading these sections to obtain a high selective filter. A design method was developed for any number of cascades both with and without an impedance transformer; the use of LCP was used to increase flexibility due to its desirable characteristics. The most desirable outcome would be filter to simultaneously control bandwidth and frequency. In order to tackle this issue the coupled line concept was adapted to incorporate frequency tunability, along with a design method being presented. Furthermore, a cascaded highpass/ lowpass filter was also explored for this concept for added flexibility in the design of a filter capable of control of both bandwidth and center frequency

High-Order Current-Mode and Transimpedance-Mode Universal Filters with Multiple-Inputs and Two-Outputs Using MOCCIIs

A high-order current-mode and transimpedance-mode universal filter with multiple-inputs and two-outputs based on multiple output second-generation current conveyors (MOCCIIs) is introduced. By choosing the input current terminals appropriately, the current-mode and transimpedance-mode lowpass, bandpass, highpass, notch or allpass filters can be obtained without component matching conditions. The proposed nth order universal filter requires (n+1) MOCCIIs, (n+1) resistors and n grounded capacitors. As examples, the first-order, biquadratic and third-order universal filters are given and compared with previous published works

Design of a bandpass oculometer

A passive oculometer is a device that measures the position of the eye by utilizing the corneo-retinal potential (CRP) generated by the eye. In this thesis, the Bandpass Oculometer replaces the joystick of a personal computer, allowing the viewer to use a computer simply by moving his eyes. Low frequency noise, present in all electronic circuits, produces an offset from the reference point, the center of the screen. In previous lowpass oculometry studies at University of Central Florida, this offset caused the cursor to drift toward the edge of the field of view within a period of 30 seconds, decreasing the ability to precisely control the cursor on the monitor. The Bandpass Oculometer is different from its predecessors in that bandpass filtering is utilized. By filtering all frequencies except where eye movement occurs, low frequency drift noise and higher frequency interference signals are eliminated. Consequently, the viewer can achieve a reference with no offset and no drift, resulting in smoother tracking and better control of the computer. An additional improvement to previous oculometers is the new computer interface. A diode shaping network is used to simulate a joystick resistance, and an optocoupler relays the output current to the computer. The optocoupler electrically isolates the viewer from the computer, thus making the system safer to use