Universal Filter Research Articles

Fully Controllable First Order Current Mode Universal Filter Composed of BJTs and a Grounded Capacitor

In this paper, a new BJT based configuration for providing first order current mode high-pass, low-pass and all-pass filter responses from the same configuration is suggested. The proposed circuit called as a universal filter possesses some important advantages such as consisting of low component count BJT and a grounded capacitor, having electronic tunability property of its pole frequency and having electronic controllability feature of filter types. The suggested circuit does not suffer from disadvantages of use of the resistors. Moreover, as an application, second order band-pass filter is also obtained by cascading two proposed filter structure. Simulations by means of PSpice program are accomplished to demonstrate the performance and effectiveness of the developed first-order universal filter. Approximately more than 1 decade tunability range is achieved. Ill. 7, bibl. 14, tabl. 3 (in English; abstracts in English and Lithuanian). http://dx.doi.org/10.5755/j01.eee.112.6.448

Development and Application of a Universal Filter in Image Processing for Automatic Interpretation of Temperature-Sensing Thermal Paints

Machines like Internal Combustion Engines and gas turbines work on the principle of converting the heat energy into mechanical energy. Every effort is taken to elevate the operating temperature which in turn increases the output efficiency. However, the engine components cannot withstand such high temperatures and their life is seriously affected. The true gradient of the temperature to which these engine components are exposed is a wealth of knowledge for an engine designer. Conventional thermometry has got many limitations from measuring and mounting point of view and is unable to give the exact thermal gradient. Advancement in thermal mapping technique is required to enhance the development of these components. Comparatively thermal paints provide a better alternative to be used as temperature sensors. These paints change their color permanently when exposed to temperature. A proper calibration and automatic interpretation of these paints using digital image processing gives a reliable thermal contour. During the engine testing the carbon exhaust from the engine blackens the color of the thermal paint applied on the various components as it flows across it creating an obstacle in the color pattern (temperature) recognition. This article highlights the efforts taken in development and application of a filter which removes the effect of the carbon soot to denoise the degraded image and recover the original image to get the required temperature profile.

An Electronically Fine-Tunable Multi-Input–Single-Output Universal Filter

A new electronically fine-tunable multi-input-single-output (MISO) universal filter is proposed. The filter circuit compared with active-device-based counterparts is very simple and fully integrable. Moreover, a few number of active transistors provide a reduction in power consumption, and the filter enjoys advantages such as no component matching and small size area. Postlayout simulation results using parameters of AMS CMOS 0.35-μm process technology show good agreement with theoretical expectations.

VERSATILE VOLTAGE-MODE DDCC-BASED UNIVERSAL FILTER

A novel versatile three-input five-output universal voltage-mode filter employing two differential difference current conveyors, two grounded capacitors and three resistors is proposed. The proposed configuration can be used as either a single-input five-output or three-input two-output. Unlike the previously reported works, it can simultaneously realize five different generic signals: low-pass, band-pass, high-pass, notch and all-pass. Moreover, the proposed circuit still offers the following advantages: (i) the employment of two grounded capacitors, (ii) no need to employ inverting-type input signals, (iii) no need to impose component choice, (iv) orthogonal control of the resonance angular frequency ωo and the quality factor Q and (v) low active and passive sensitivity performances.

FULLY CASCADABLE MIXED-MODE UNIVERSAL FILTER BIQUAD USING DDCCS AND GROUNDED PASSIVE COMPONENTS

A fully cascadable (i.e., low/high input impedance for current/voltage input signals and high/low output impedance for current/voltage output signals) mixed-mode (input and output signals can be voltage or current) universal filter biquad by using three differential difference current conveyors (DDCCs), three grounded resistors, and two grounded capacitors is presented in this paper. The proposed biquad can realize the inverting, non-inverting, and differential types universal filtering responses (lowpass, highpass, bandpass, notch, and allpass) from the voltage and current output terminals without changing the filter topology. The proposed circuit is suitable for cascading in all the four possible modes (i.e., voltage, current, transresistance, and transconductance modes). Moreover, the proposed mixed-mode biquad still enjoys (i) using only grounded passive components, (ii) no need of extra inverting and non-inverting amplifiers for special input signals, and (iii) low active and passive sensitivities. This paper also shows how analytical synthesis can be used to produce the proposed mixed-mode filter circuit. H-Spice simulation results confirm the theory.

BANDWIDTH EXPANSION METHODS OF INDUCTANCE SIMULATOR CIRCUITS AND VOLTAGE-MODE BIQUADS

In this paper, novel low and high frequency performance improvement techniques are proposed. High frequency performance improvement method is based on the single pole effect reduction/completely elimination by creating a corresponding zero while a low one is based on reduction/elimination of Z terminal parasitic resistors. Therefore, two grounded capacitance multipliers, three grounded inductor simulators, a floating inductor and a voltage-mode (VM) universal filter using second-generation current conveyors (CCIIs) are used to explain the developed methods. One of the grounded inductor simulators, floating simulated inductor and VM biquad are novel. Further, both of the new simulated inductors use a grounded capacitor; accordingly, they are suitable for IC fabrication. However, all the proposed circuits need a single matching condition. A number of simulations through PSPICE program and experimental tests are accomplished to demonstrate the workability, performance and effectiveness.

Single-input three-output electronically tunable universal current-mode filter using current follower transconductance amplifiers

In this paper, an electronically tunable universal filter configuration with single input and three outputs (SITO) employing a recently introduced active device namely current follower transconductance amplifier (CFTA) is described. The proposed filter is composed of four CFTAs and two grounded capacitors, and is capable of realizing all the standard functions of the universal filter without requiring any component matching criterions and any extra active components. It exhibits low-input and high-output impedances, which is highly desirable for cascading in current-mode. It also offers the advantage feature of an independent electronic adjustment of the natural angular frequency ( ω o ) and the quality factor ( Q) by means of tuning the external bias currents. Moreover, a high Q-value filter can be obtained by simply adjusting the appropriate ratio of bias currents. The analysis of active and passive sensitivities is shown to be low. In order to demonstrate the performance of the proposed circuit, PSPICE simulation results are provided.

Voltage Mode Universal Biquad Using CCCII

This paper proposes a multi-input single-output (MISO) second-order active-C voltage mode (VM) universal filter using two second-generation current-controlled current conveyors (CCCIIs) and two equal-valued capacitors. The proposed circuit realizes low pass, band pass, high pass, all pass, and notch responses from the same topology. The filter uses-minimum number of passive components and no resistor which is suitable for IC Design. The filter enjoys low-sensitivity performance and exhibits electronic and orthogonal tunability of pole frequency () and quality factor () via bias current of CCCIIs. PSPICE simulation results confirm the theory.

Tunable Universal Filter with Current Follower and Transconductance Amplifiers and Study of Parasitic Influences

A universal filter with dual-output current follower (DO-CF), two transconductance amplifiers (OTAs) and two passive elements is presented in this paper. The filter is tunable, of the single-input multiple-output (SIMO) type, and operates in the current mode. Our solution utilizes a low-impedance input node and high-impedance outputs. All types of the active elements used can be realized using our UCC-N1B 0520 integrated circuit and therefore the paper contains not only simulation results that were obtained with the help of behavioral model of the UCC-N1B 0520 element, but also the characteristics that were gained by measurement with the mentioned circuit. The presented simulation and measurement results prove the quality of designed filter. Similar multi-loop structures are very-well known, but there are some drawbacks that are not discussed in similar papers. This paper also contains detailed study of parasitic influences on the filter performance.

VM and CM Universal Filters Based on Single DVCCTA

A universal voltage-mode filter (VM) and a current-mode filter (CM) based on recently proposed active building block, namely, differential voltage current conveyor transconductance amplifier (DVCCTA) are proposed. Both the circuits use a single DVCCTA, two capacitors, and a single resistor. The filters enjoy low-sensitivity performance and low component spread and exhibit electronic tunability of filter parameters via bias currents of DVCCTA. SPICE simulation using 0.25 μm TSMC CMOS technology parameters is included to show the workability of the proposed circuits.

Differential Difference Current Conveyor Transconductance Amplifier: A New Analog Building Block for Signal Processing

A new active building block for analog signal processing, namely, differential difference current conveyor transconductance amplifier (DDCCTA), is presented, and performance is checked through PSPICE simulations which show the usability of the proposed element is up to 201 MHz. The proposed block is implemented using 0.25 μm TSMC CMOS technology. Some of the applications are presented using the proposed DDCCTA, namely, a voltage mode multifunction filter, a current mode universal filter, an oscillator, current and voltage amplifiers, and grounded inductor simulator. The feasibility of DDCCTA and its applications is confirmed via PSPICE simulations.

Versatile Voltage-Mode Universal Filter Using Differential Difference Current Conveyor

A novel four-input three-output voltage-mode differential difference current conveyor (DDCC) based universal filter is presented. The circuit uses three DDCCs as active elements, two resistors and two capacitors as passive elements. The circuit along with its versatility enjoys the advantage of minimum number of passive elements employment. SPICE simulation results are given to confirm the theoretical analysis. The proposed circuit is a novel addition to the existing knowledge on the subject.

Single MO-CCCCTA-Based Electronically Tunable Current/Trans-Impedance-Mode Biquad Universal Filter

This paper presents an electronically tunable current/trans-impedance-mode biquad universal filter employing only single multi-output current controlled current conveyor trans-conductance amplifier (MO-CCCCTA) and two grounded capacitors. The proposed filter realizes all the standard filter func-tions i.e. low pass (LP), band pass (BP) and high pass (HP), notch and all pass (AP) filters in the current form at high impedance output through appropriate selection of the input signals, without any matching conditions. Simultaneously, it can also realize all the standard filter functions in trans-impedance form from the same circuit topology. The circuit does not require inverting-type input current signal(s) and double input current signal(s) to realize all the responses in the design. The validity of proposed filter is verified through PSPICE simulations.

Analytical synthesis and comparison of voltage‐modeNth‐order OTA‐C universal filter structures

SUMMARYComplementary single‐ended‐input operational transconductance amplifier (OTA)‐based filter structures are introduced in this paper. Through two analytical synthesis methods and two transformations, one of which is to convert a differential‐input OTA to two complementary single‐ended‐input OTAs, and the other to convert a single‐ended‐input OTA and grounded capacitor‐based one to a fully differential OTA‐based one, four distinct kinds of voltage‐modenth‐order OTA‐C universal filter structures are proposed. TSMC H‐Spice simulations with 0.35µm process validate that the new complementary single‐ended‐input OTA‐based one holds the superiority in output precision, dynamic and linear ranges than other kinds of filter structures. Moreover, the new voltage‐mode band‐pass, band‐reject and all‐pass (except the fully differential one) biquad structures, all enjoy very low sensitivities. Both direct sixth‐order universal filter structures and their equivalent three biquad stage ones are also simulated and validated that the former is not absolutely larger in sensitivity than the latter. Finally, a very sharp increment of the transconductance of an OTA is discovered as the operating frequency is very high and leads to a modified frequency‐dependent transconductance. Copyright © 2010 John Wiley & Sons, Ltd.

A tunable universal terahertz filter using artificial dielectrics based on parallel-plate waveguides

Using parallel-plate waveguides (PPWGs) that mimic artificial dielectrics, we demonstrate a universal filter that provides low-pass, high-pass, band-pass, and band-stop (or notch) filtering functionalities in the terahertz (THz) frequency regime. The device essentially consists of two PPWGs in a complementary geometry. The filtering functionality is achieved by positioning an appropriate amplitude mask in the path of the spatially chirped THz beam between the two waveguides. By varying the position of the mask, we experimentally and theoretically demonstrate continuous tunability of the respective 3 dB cutoff frequencies within the frequency range from about 0.3 to 0.7 THz.

A new current-mode current-controlled SIMO-type universal filter

This paper proposes a new current-mode current-controlled single input multiple output (SIMO) type universal filter. The proposed circuit employs two current-controlled current conveyors (CCCIIs), one MO-CCCA (current-controlled current amplifier with multi-outputs) and two grounded capacitors. The filter can simultaneously realize lowpass, bandpass, highpass, bandstop and allpass filter outputs, and offers an independent electronic control of the natural angular frequency ( ω 0 ) and quality factor ( Q) by means of adjusting the bias currents of the CCCIIs. The parameter sensitivities are small. Moreover, a high Q-value filter can be easily obtained by adjusting the ratio of two bias currents of MO-CCCA. PSPICE simulation results are given to demonstrate the advantages of the proposed circuit.

New electronically tunable current-mode universal biquad filter using translinear current conveyors

In this study, a new electronically tunable current-mode universal filter with two inputs and two outputs employing one translinear current conveyor, one translinear current conveyor with controlled current gain and two grounded capacitors is presented. The proposed circuit offers the following attractive features: realisation of low-pass, band-pass, high-pass, band-stop and all-pass current responses from the same configuration; employment of the minimum active and passive components; no requirement of component matching conditions; independent current-control of the parameters natural frequency (ωo) and quality factor (Q); low active and passive sensitivities; and high impedance output. The characteristics of the proposed circuit are simulated using PSPICE to confirm the theory.

Realization of Tunable Pole-Q Current-Mode OTA-C Universal Filter

A realization of a current-mode operational transconductance amplifier-capacitor (OTA-C) universal filter with tunable pole-Q is proposed. A biquadratic band-reject function is used as the initial synthesis function based on three integrator blocks. Consequently, the proposed filter uses a total of three multiple-output OTAs and three grounded capacitors. Five types of transfer functions, namely, low-pass, high-pass, band-pass, band-reject, and all-pass responses, can be obtained without changing the circuit topology. The pole-Q (Q0) and the pole-frequency (ω0) parameters are independently tuned. The Q0 and ω0 parameters are electronically tuned by adjusting the transconductance gains of the OTAs. Furthermore, Q0 can be tuned by varying the capacitor manually without affecting ω0. SPICE simulation results of the proposed filter are presented.

Design and verification of an ALU‐based universal FIR filter

PurposeTraditionally, each time a new design for a finite impulse response (FIR) filter is required, a new algorithm has to be developed specially for the FIR filter. Furthermore, corresponding hardware architecture must be designed specially to meet the requirement of the FIR specifications. The purpose of this paper is to propose an arithmetic logic unit (ALU)‐based universal FIR filter suitable for realization in field programmable gate arrays (FPGA), where various FIR filters can be implemented just by programming instructions in the ROM with identical hardware architecture.Design/methodology/approachRather than multiplier‐accumulator‐based architecture for conventional FIR, the proposed ALU architecture implements the FIR functions by using accumulators and shift‐registers controlled by the instructions of ROM. Furthermore, time division multiplexing access (TDMA) technique is employed to reduce the chip size. In addition, the proposed FIR architecture is verified in a SOC hardware and/or software co‐emulation system.FindingsAn ALU‐based universal FIR filter suitable for realization in FPGA is designed and verified in a SOC hardware/software co‐emulation system with example of a 64‐tap FIR filter design.Originality/valueA software‐based design method as well as TDMA scheme for the ALU‐based FIR filter are introduced, making FIR filter architecture universal, programmable, and consuming less FPGA resources.

CMOS-based current-controlled DDCC and its applications to capacitance multiplier and universal filter

This paper presents design of an active building block for analog signal processing, named as current-controlled differential difference current conveyor (CCDDCC). Its parasitic resistances at X-terminal can be controlled by an input bias current. The proposed element is realized in a CMOS technology. It displays usability of the new active element, where the maximum bandwidth of voltage and current followers are around 1 GHz, 100 MHz, respectively. The THD is obtained around 0.8% within 0.6 Vp–p input range. The power dissipation of a CCDDCC at 10 μ A biased current is obtained around 1.35 mW with ± 1.25 V power supplies. In addition, grounded capacitor-based floating capacitance multiplier and current-mode (CM) multiple-input single output (MISO) second-order universal analog filters are included as the applications. For realization of a grounded capacitor-based floating capacitance multiplier, it employs three CCDDCCs and one grounded capacitor without resistor connections. The capacitance can be tuned electronically through the bias current. The filter offers the simultaneous realization five type standard filter responses. The quality factor and the frequency response parameters can be independently tuned. The non-ideal effects of the developed structures are examined. SPICE simulation results of proposed CCDDCC and its applications are also presented.