High-pass Filter Responses Research Articles

MO-CCCII-Based Single-Input Multi-Output (SIMO) Current-Mode Fractional-Order Universal and Shelving Filter

This study introduces an innovative filter topology capable of providing simultaneous positive and negative gain outputs for one-fractional order LP, with high-pass, all-pass, and fractional-order shelving filter responses. The circuit, utilizing multi-output second-generation current-controlled conveyors, stands out as the first to deliver ten outputs, incorporating both integer and fractional-order filter responses, without requiring additional components. Its current-mode design simplifies the process, employing minimal active and grounded passive elements, making it appropriate for low-voltage/low-power applications. The filter utilizes fifth-order Oustaloup approximation and Foster type-I RC networks for fractional-order capacitors, providing enhanced control over the transition slope. PSpice simulations confirmed a 1 kHz cut-off, showcasing low power consumption, minimal noise, and a wide dynamic range, positioning the filter as suitable for sensors, control, and acoustic applications.

Voltage-Mode Multifunction and Universal Biquads with Two CFOAs

In this paper, a new voltage-mode (VM) multifunction filter including only two grounded capacitors, three resistors, and two current feedback operational amplifiers is introduced. This filter with one high input impedance and two low output impedances can simultaneously provide band-pass filter (BPF) and low-pass filter (LPF) responses with an adjustable gain. A universal VM filter topology with three inputs and one output generating high-pass filter (HPF), BPF, LPF, notch filter, and all-pass filter (APF) responses is obtained from the multifunction one. It has the same number of active and passive elements as the multifunction and a low output impedance. Sensitivities of both introduced filters are low enough. However, the APF of the introduced universal filter has a passive element-matching problem. As an example, parasitic impedance effects are considered for the LPF of the universal filter, while non-ideal gain analyses are given for the HPF. To see how the introduced universal filter works, countless simulations are performed through the SPICE (Simulation Program with Integrated Circuit Emphasis) program in which 0.13 [Formula: see text]m IBM CMOS technology parameters are utilized. DC supply voltages are selected as ± 0.9 V. Also, several experiments using commercially available AD844s with ± 10 V supply voltages are carried out to see the performance.

A New Electronically Tunable Transimpedance-Mode OTA-Based First-Order Universal Filter and its Quadrature Oscillator Application

This paper suggests a new operational transconductance amplifier (OTA) based electronically tunable transimpedance-mode first-order universal filter (FOUF). The suggested FOUF produces all-pass (AP), high-pass (HP) and low-pass (LP) filter responses simultaneously. It employs three OTAs, two grounded resistors and only one grounded capacitor. Owing to use of grounded passive elements, the suggested FOUF is suitable for integrated circuit implementation. It operates at low power supply voltages. Additionally, the resonance frequency of the suggested AP filter can be adjusted in a wide frequency range. However, the suggested FOUF consists of only one matching condition. Moreover, a sinusoidal quadrature oscillator (QO) application that is derived from the suggested FOUF topology is given. The suggested FOUF and its QO application are simulated by using 0.18-[Formula: see text]m TSMC technology parameters in the SPICE program to validate the presented theory. Finally, an experimental test is performed to demonstrate workability of the suggested AP filter.

A Novel DDCC-Based Current-Mode Two-Integrator-Loop Active-C Biquad

In this study, a novel DDCC-based two-integrator-loop universal active-C biquad with a companding process scheme is proposed. The proposed filter employs some processing blocks such as integrators and summing blocks. The use of the block diagram design procedure is attractive and systematic. The state space synthesis technique is utilized for the topology of the integrator design. Several advantages of the proposed filter are briefly expressed as: simultaneously realizing five second-order filter functions such as low-pass, high-pass, band-pass, all-pass and notch filter responses; offering resistorless realization; dissipating low power; having electronic tunability feature of its pole frequency and quality factor orthogonally; not suffering from disadvantages of the passive element matching problems. Some simulation results including frequency and time domain analysis results by using the PSpice program are carried out to confirm the theoretical ones. All the obtained simulation results are discussed.

A 5-Gb/s Adaptive Continuous Time Linear Equalizer Using Ferroelectric Capacitor

This article presents a 5-Gb/s continuous-time linear equalizer (CTLE) for serial link interface where adaptive nature is achieved using a ferroelectric capacitor. This barium strontium titanate (BST)-based STPTIC-15G2 capacitor model from STMicroelectronics provides a smooth 5:1 tuning range for a voltage range of 0&#x2013;18 V and eliminates the use of blocking capacitor required in case of varactor diode. The tunability of the high-pass filter response of the proposed CTLE provides the flexibility to meet the allocated loss budget of any serial link more precisely than a design with a discrete value capacitor. Also, its design methodology is much simpler than conventional MOSFET-based CTLE. Moreover, it avoids the use of complex algorithms seen in the case of digital equalization. For validation, the design is implemented on an FR4 board. While studying the data rate tolerance and channel tolerance of the printed prototype, the measured results closely match the simulation results. The compensation level of the equalizer is verified for an FR4 channel by varying its length from <inline-formula> <tex-math notation="LaTeX">$7^{\prime \prime }$ </tex-math></inline-formula> to <inline-formula> <tex-math notation="LaTeX">$28^{\prime \prime }$ </tex-math></inline-formula> which is equivalent to a change in insertion loss from 1.3 to 5.2 dB at 2.5 GHz, which is the Nyquist frequency for a 5-Gb/s signal. Also, for a <inline-formula> <tex-math notation="LaTeX">$28^{\prime \prime }$ </tex-math></inline-formula> FR4 channel, a channel loss requirement of 8&#x2013;9.5 dB is achievable by simply varying the applied bias to the ferroelectric capacitor from 0 to 10 V.

CNTFET based Voltage Mode MISO Active only Biquadratic Filter for Multi-GHz Frequency Applications

A new voltage mode, carbon nanotube field-effect transistor (CNTFET) based multiple input single output active only biquadratic filter (AOBF), is presented. The proposed AOBF employs simple and compact single ended transconductance elements, voltage-controlled resistor (VCR) and varactor. The proposed AOBF provides band-pass filter, band-reject filter, all-pass filter, high-pass filter and low-pass filter responses, just by selecting the appropriate inputs. The AOBF operates at low-voltage supply of 0.7 V and suitable for integration due to absence of any external passive component. The realized AOBF also enjoys the attractive features of orthogonal voltage-controlled tuning of its pole-Q and pole-ωo, low incremental sensitivity performance and suitability for multi-GHz frequency applications. The pole-Q of the filter is controlled through CNTFET-based VCR while the pole-ωo is controlled through the CNTFET-based varactor. To validate the performance, HSPICE simulation on the designed AOBF was carried out using Stanford CNTFET model at 16 nm technology node. The simulation results thus obtained, justify the theory proposed.

CMOS realization of electronically tunable VDCC based single-input-dual-output filter

This paper introduces a CMOS implementation of filter application based on single Voltage Differencing Current Conveyor (VDCC). The filter employs a single VDCC, one floating capacitor and three grounded passive components. The designed filter can simultaneously implement the band-pass and high-pass filtering responses. By means of the trans-conductance gain of the VDCC, the angular frequency and quality factor of the filter can be dynamically modified. Furthermore, avoid conflicting with the natural frequency, the quality factor can also be tuned. Layout, pre and post layout simulations are carried out for the circuits, the proposed filter which occupies 68μm×23μm area excluding the area of the passive components, using 0.18μm AMS CMOS process parameters in Cadence environment. The proposed VDCC structure can utilize additional high-impedance z-copy terminal. The natural frequency of the filter is designed as 100MHz which is suitable for the RF applications. Post-layout simulations with noise, THD, PVT, and Monte Carlo analyzes are conducted with the Spectre simulator to assess the feasibility of the developed structures. The findings of the simulations are found to be closely in consistent with the theoretical research.

Miniaturized composite band pass filter using folded transmission lines for wideband radar

A composite design of Band Pass Filter (BPF) is developed with 3-dB fractional bandwidth (FBW) of more than 140%. This BPF is suitable for the development of wideband radar, communication and EW system in 1 to 6 GHz. Composite BPF design utilizes stepped impedance Low Pass Filter (LPF) along with the quarter wavelength (λg/4) short circuited stub. λg/4 short circuited stubs incorporated High Pass Filter (HPF) response which transforms overall design into BPF. Four cases of filter have been discussed. In case-I, the proposed BPF is developed with a size of 32.6 mm X 7.0 mm. Further in case-II, design has been realized with improved roll-off at the lower edge of the bandwidth (i.e., 1GHz). In case-III, developed design is 75% length-wise miniaturized that of case-I. Further in case-IV, about 55% length-wise miniaturization is done. Case-III and IV have their response similar to that of the case-I with miniaturized design. All designs are simulated, optimized and fabricated over RT-Duroid 5880 substrate. For case-I, III and IV fabrication has been done on 20 mil thick substrate, whereas for case-II 31 mil thick substrate is used. Comparisons between all the cases have been presented in tables and S-parameter plots.

A Current Mode Design of Fractional Order Universal Filter

In this paper, low-voltage active elements based a general filter topology, which provides fractional order low-pass, high-pass, band-pass and band-reject filter responses at the same ...

DX-MOCCII Based Fully Cascadable Second Order Current-Mode Universal Filter

The paper presents a new second-order single input multiple output (SIMO) type current mode (CM) universal filter. The proposed circuit uses two dual-X second generation multi-output current conveyors (DX-MOCCII), two grounded capacitors and three grounded resistors. The circuit configuration realizes low-pass filter (LPF), high-pass filter (HPF), band-pass filter (BPF), notch filter (NF) and all-pass filter (APF) responses simultaneously at different output terminals. The new circuit enjoys the features of low input impedance and high output impedance, which is desirable and useful for cascadability in CM circuits. For realizing the universal filter responses, the proposed circuit configuration does not require matching constraint of passive components and both active and passive sensitivities are found low. In addition, the extension of the proposed circuit as a resistorless universal filter has also been presented. As an application of the proposed filter, inverting band pass output is connected to a negative unity gain current follower in a close loop to design voltage and CM multiphase sinusoidal oscillators (MSOs). Comparison of the proposed configuration with available literature is given. The PSPICE simulation of the filter and its application as MSO are performed to verify the agreement with the theoretical proposition.

New Configuration for OFCC-Based CM SIMO Filter and its Application as Shadow Filter

This paper puts forward a new operational floating current conveyor (OFCC)-based current mode (CM) single input multiple output (SIMO) filter configuration which uses two grounded capacitors, three grounded resistors and three OFCCs. The attractive features of the proposed filter are—use of grounded passive elements; availability of low pass, band pass, high pass and notch filter responses simultaneously at high output impedance; and independent adjustment of filter parameters. These features make the proposed filter suitable from fabrication viewpoint and allow easy cascading. Effect of nonidealities on proposed filter response is also examined. A CM shadow filter is also built by introducing an OFCC-based amplifier and connecting it in a feedback loop of the proposed SIMO filter. This configuration allows adjustment of filter parameters through gain of amplifier. MOS-based implementation of grounded resistors is incorporated to facilitate electronic tuning of filter parameters. The operation of the proposed filters is verified through SPICE simulations using $$0.5\,\upmu \hbox {m}$$ technology model parameters from MOSIS (AGILENT). Proposed CM SIMO filter is prototyped using commercially available IC AD844, and experimental response is found to be in close agreement with theoretical ones.

Designing an Inverter-based Operational Transconductance Amplifier-capacitor Filter with Low Power Consumption for Biomedical Applications

The operational transconductance amplifier-capacitor (OTA-C) filter is one of the best structures for implementing continuous-time filters. It is particularly important to design a universal OTA-C filter capable of generating the desired filter response via a single structure, thus reducing the filter circuit power consumption as well as noise and the occupied space on the electronic chip. In this study, an inverter-based universal OTA-C filter with very low power consumption and acceptable noise was designed with applications in bioelectric and biomedical equipment for recording biomedical signals. The very low power consumption of the proposed filter was achieved through introducing bias in subthreshold MOSFET transistors. The proposed filter is also capable of simultaneously receiving favorable low-, band-, and high-pass filter responses. The performance of the proposed filter was simulated and analyzed via HSPICE software (level 49) and 180 nm complementary metal-oxide-semiconductor technology. The rate of power consumption and noise obtained from simulations are 7.1 nW and 10.18 nA, respectively, so this filter has reduced noise as well as power consumption. The proposed universal OTA-C filter was designed based on the minimum number of transconductance blocks and an inverter circuit by three transconductance blocks (OTA).

Universal Pseudo-Differential Filter Using DDCC and DVCCs

In the paper, a universal preudo-differential second-order filter operating in voltage mode, where both intup and output are differential, is presented. The circuit is formed by one differential difference current conveyor (DDCC), two differential voltage current conveyors (DVCCs), and five passive elements. The filter is characterized by high input impedance, minimum number of passive elements that are all grounded, and high common-mode rejection ratio (CMRR). The proposed filter structure is able to realize all five standard frequency filter responses. Non-ideal analysis has been performed by considering the real parasitic parameters of the active elements. The optimization of passive element values has been done in terms of minimal shift of the pole-frequency and to obtain the maximum stop-band attenuation of the high-pass filter response. Functionality is verified by simulations and experimental measurements using readily available integrated circuit UCC-N1B 0520. DOI: http://dx.doi.org/10.5755/j01.eie.23.6.19694

A shared neural integrator for human posture control.

Control of standing posture requires fusion of multiple inputs including visual, vestibular, somatosensory, and other sensors, each having distinct dynamics. The semicircular canals, for example, have a unique high-pass filter response to angular velocity, quickly sensing a step change in head rotational velocity followed by a decay. To stabilize gaze direction despite this decay, the central nervous system supplies a neural "velocity storage" integrator, a filter that extends the angular velocity signal. Similar filtering might contribute temporal dynamics to posture control, as suggested by some state estimation models. However, such filtering has not been tested explicitly. We propose that posture control indeed entails a neural integrator for sensory inputs, and we test its behavior with classic sensory perturbations: a rotating optokinetic stimulus to the visual system and a galvanic vestibular stimulus to the vestibular system. A simple model illustrates how these two inputs and body tilt sensors might produce a postural tilt response in the frontal plane. The model integrates these signals through a direct weighted sum of inputs, with or without an indirect pathway containing a neural integrator. Comparison with experimental data from healthy adult subjects (N = 16) reveals that the direct weighting model alone is insufficient to explain resulting postural transients, as measured by lateral tilt of the trunk. In contrast, the neural integrator, shared by sensory signals, produces the dynamics of both optokinetic and galvanic vestibular responses. These results suggest that posture control may involve both direct and indirect pathways, which filter sensory signals and make them compatible for sensory fusion.NEW & NOTEWORTHY Control of standing posture requires fusion of multiple inputs including visual, vestibular, somatosensory, and other sensors, each having distinct dynamics. We propose that postural control also entails a shared neural integrator. To test this theory, we perturbed standing subjects with classic sensory stimuli (optokinetic and galvanic vestibular stimulation) and found that our proposed shared filter reproduces the dynamics of subjects' postural responses.

A New DVCC+ Based Second-Order Current-Mode Universal Filter Consisting of Only Grounded Capacitors

In this paper, a new second-order current-mode universal filter using only two plus-type differential voltage current conveyors, three resistors and two grounded capacitors is proposed. The proposed circuit with two identical inputs and three outputs can simultaneously provide second-order high output impedance low-pass, band-pass and notch filter responses. Also, it can realize high-pass and all-pass filter responses with interconnection of relevant output currents. It can be easily tuned electronically. It can be operated properly at high frequencies. A number of simulations based on SPICE program and an experimental test are achieved in order to demonstrate the performance of the proposed filter.

Current-Mode nth-Order Filter Based on a Minimal Component

In this paper, a new active current-mode (CM) minimal component, cascaded current differencing unit (CCDU) and a CM nth-order filter based on the CCDU have been presented. The proposed CCDU simplifies the design of the CM nth-order filter circuit considerably. The proposed nth-order circuit, which adopts only an active component and n grounded capacitors, can simultaneously realize low-pass (LP), band-pass (BP) and high-pass (HP) filter responses. It enjoys the simple configuration and is suitable for integrated circuit (IC) fabrication. PSPICE simulations and experimental tests for CM third-order filter based on this structure have also been conducted and the results have good agreement with the theoretical analysis.

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

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 transadmittance-mode. 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.

REALIZATION OF FIRST-ORDER CURRENT-MODE FILTERS WITH LOW NUMBER OF MOS TRANSISTORS

In this paper, a new current-mode (CM) circuit for realizing all of the first-order filter responses is suggested. The proposed configuration contains low number of components, only two NMOS transistors both operating in saturation region, two capacitors and two resistors. Major advantages of the presented circuit are low voltage, low noise and high linearity. The proposed filter circuit can simultaneously provide both inverting and non-inverting first-order low-pass, high-pass and all-pass filter responses. Computer simulation results achieved through SPICE tool and experimental results are given as examples to demonstrate performance and effectiveness of the proposed topology.

Sharpening enhancement of Computed Tomography (CT) images using Hyperbolic Secant Square filter

In Computed Tomography (CT) imaging, selection of reconstruction kernels determines the tradeoff between image sharpness and pixel noise. This paper presents a new High Pass (HP) filter to sharp the acquired CT images without unnatural pronounced edges. Sensitivity to noise and limited directions are the major drawbacks of conventional HP filters used in image sharpening. To combat with these difficulties a two Dimensional (2D) isotropic Hyperbolic Secant Square (HBSS) filter is developed. The 2D non-separable property of this filter improves the directional selectivity while the HBSS provide less noise sensitivity and least square design present the regularization. The improved HP filter responses are used to sharp the CT images. The performance of proposed sharpening method is compared with common unsharp mask, which uses non-separable isotropic Laplacian of Gaussian (LoG).

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