Showing papers on "Low-pass filter published in 2022"

Extension of recently proposed two-CFOA-GC all pass filters to the realisation of first order universal active filters

Abstract: Recently, six new all pass filter (APF) configurations, each employing two current feedback operational amplifiers (CFOA) and a grounded capacitor, were presented. This communication extends the utility of the earlier configurations by demonstrating that by some simple alterations of the various connections, all of them can be extended to yield first order universal active filter (UAF) configurations capable of realising all the three first order filters, namely, low pass, high pass and all pass without using any additional components. All the presented filter configurations possess high input impedance and low output impedance to facilitate easy cascading and also offer the tunability of the cut-off frequency/pole frequency and gain. Experimental results employing off-the-shelf AD844-type IC CFOAs have been included which validate the theoretical formulations.

Fully Differential Current-Mode Configuration for the Realization of First-Order Filters with Ease of Cascadability

Abstract: It is well known that fully differential signal processing is more advantageous than single-ended signal processing in a noisy environment, and is widely used in audio, video and other signal processing applications. This paper introduces a new fully differential configuration that contains a first-order low-pass (LP) filter, high-pass (HP) filter, and all-pass (AP) filter, all present within the same circuit design. The proposed fully differential configuration is simple and employs only one multiple-output current differencing transconductance amplifier and one grounded capacitor. The circuit has a wide operating frequency range (up to 73 MHz). The additional features offered by the proposed circuit include use of the lowest number of active and passive components, suitability of the integrated circuit chip, support of cascadability, electronic tunability, no passive component-matching restrictions, availability of all first-order responses, i.e., LP, HP, and AP, and low-level operating supply voltages. Non-ideal and parasitic analyses are investigated for the proposed circuit, and PSPICE simulation results are presented to verify the proposed theory. Additionally, the proposed FD LP filter circuit is experimentally verified using off-the-shelf ICs. Moreover, the cascading feasibility is demonstrated by realizing a fully differential nth-order LP filter.

0.342 nW Class-AB enhanced flipped source follower low pass filter for biomedical applications.

Abstract: Owing to the impact of process voltage and temperature variations, the design of low-power low-pass filters (LPFs) with improved linearity is still one of the most challenging tasks for effective biological signal processing. This paper presents the design of a fourth-order Class-AB enhanced flipped source follower (EFSF) LPF circuit aimed at the detection of electroencephalography signals. The simulated results attained using complementary metal-oxide-semiconductor 180 nm technology node in Cadence Analog Design Environment demonstrate that the EFSF LPF emulates a DC-gain of -88 mdB with a bandwidth of 100 Hz and consumes 0.342 nW power from a supply voltage of 0.5 V. The calculated figure of merit for the proposed filter is 5.983 × 10-15 J with a dynamic range (DR) of 43.54 dB and input-referred noise of 91 µVrms. It consumes an area of 0.0458 mm2. To check the robustness of the proposed filter circuit, we performed Monte Carlo simulations with 200 runs. The statistical results achieved for the DC-gain, DR, and total harmonic distortion of the proposed filter show mean values of -188.09 mdB, 43.10 dB, and -41.85 dB along with standard deviation values of 285.21 mdB, 718.72 mdB, and 4.52 dB, respectively. The proposed Class-AB EFSF LPF can be used to achieve high power efficiency in future low-voltage and low-power biological systems.

Discrete Multiple Second-Order Generalized Integrator With Low-Pass Filters and Frequency-Locked Loop for DC Rejection

Abstract: The multiple second-order generalized integrator (MSOGI), which is composed of parallel second-order generalized integrators (SOGI), is widely used in grid synchronization and signal extraction, and it usually suffers from dc offset issue. In continuous domain, low-pass filter (LPF) can be added to SOGI to eliminate the dc offset in its quadrature channel. However, in digital implementation, directly discretized LPF-based methods may not be able to eliminate dc offset and ac discretization error simultaneously, where the steady-state error will also be introduced by the conventional frequency-locked loop (FLL). In this article, a modified impulse invariant method is adopted to discretize SOGIs, which presents zero ac errors and good dynamics, but shows dc offset in both output channels. Then, an LPF is introduced to eliminate the dc offset of the discrete SOGI, forming a discrete SOGI-LPF. And, a discrete MSOGI-LPF (DMSOGI-LPF) is formed by paralleling multiple DSOGI-LPFs, which can extract different frequency components. Furthermore, a discrete FLL is proposed to estimate the frequency of the input signal, which suppresses the influence of the dc offset and achieves good dynamics. Finally, the stability analysis of the proposed method based on discrete linear-time periodic (LTP) model is provided. The effectiveness of the proposed method and its discrete LTP model are validated through experimental results.

Design of a Low-Noise Low-Power Fourth Order Complementary Super Source Follower Filter for EEG Applications

Abstract: Design of a filter for biomedical application is a challenging task owing to its low-power and low-noise values introduced at low frequencies. This paper describes the design of a Complementary Super Source Follower (CSSF-C) Low Pass Filter (LPF) circuit and the same has been compared with Complementary Source Follower (CSF-C) LPF targeted for the detection of EEG signals. Simulated results obtained in Cadence Analog Design Environment using CMOS 0.18 µm technology node shows the CSSF-C LPF circuit emulates gain of -528 mdB, bandwidth of 100 Hz, power consumption of 12.6 nW from 0.5 V supply voltage. Further, the proposed LPF circuit is capable of achieving Dynamic Range (DR) of 63 dB with an Input Referred Noise (IRN) of 36 µVrms. The proposed CSSF-C LPF is expected to improve the quality of acquired EEG signals.

Optimization design of fractional‐order Chebyshev lowpass filters based on genetic algorithm

Abstract: Fractional‐order filters have received extensive attention from international scholars because of their greater design freedom and continuously stepped stopband attenuation rate. Based on genetic algorithm (GA), this paper proposes an optimum design approach for fractional‐order Chebyshev lowpass filters that meet design specifications. The fractional order and ripples attenuation of the normalized Chebyshev lowpass filter are calculated according to specifications, the integer order in the Chebyshev polynomial is replaced with the calculated fractional order, and then the fractional‐order Chebyshev polynomial is substituted into the magnitude response of the normalized Chebyshev lowpass filter along with the ripples attenuation to achieve the ideal response. The transfer function parameters of a fractional‐order filter are optimized using GA to make the magnitude response approximate the ideal response described above. This completes the optimized design of a fractional‐order Chebyshev filter that meets specifications. Given three different sets of design specifications, the fractional‐order Chebyshev filter designed using the proposed method is compared with one designed by another method in the literature. Finally, design examples are presented, stability analysis and Pspice simulations are performed, and an actual circuit is constructed to illustrate the effectiveness of the proposed method.

Mixed-Mode Electronically-Tunable First-Order Universal Filter Structure Employing Operational Transconductance Amplifiers

Abstract: In this paper, a new mixed-mode first-order universal filter configuration is presented that employs three operational transconductance amplifiers (OTAs) and one grounded capacitor (eminently suitable for IC chip fabrication). All three first-order generic filter functions, namely low pass filter (LPF), high pass filter (HPF) and all pass filter (APF) in all the four possible modes, namely voltage mode (VM), current mode (CM), transresistance mode (TRM) and transconductance mode (TCM) can be realized. The proposed configuration offers high input impedance and high output impedance. The pole frequency of the filter can be controlled electronically by varying a single transconductance. Nonideal analysis of the proposed filter structure has also been carried out and the results have been compared with those obtained from ideal analysis. The performance of the presented filter configuration has been corroborated through PSPICE simulations as well as experimental results. The various simulation and experimental results validate the practical viability of the proposed configurations.

A Harmonic-Free Wilkinson Power Divider Using Lowpass Resonators

Abstract: This paper presents a Wilkinson power divider (WPD) capable of suppressing unwanted bands up to 16th harmonic with high isolation. In this WPD, a lowpass filter composed of a main resonator and three bended stubs are used to guarantee a wide stopband. The presented WPD illustrates suitable performance at 0.85 GHz for GSM applications. Isolation between of output ports, input return loss and insertion loss are better than 24 dB, 20 dB and 3.4 dB, respectively.

Implementation of Embedded Magnetic Encoder for Rotor Position Detection Based on Arbitrary Phase-Shift Phase-Lock Loop

Abstract: Rotor position is essential in control of permanent magnet synchronous motors (PMSMs). In terms of resolution, structural complexity, occupied volume, anti-interference ability, environmental adaptability, and cost, embedded magnetic encoder based on linear Halls owns strong competitiveness. When linear Hall sensors are selectively installed at stator slot openings in extremely compact scenario, signal phase-shift asymmetry between two or three Hall sensors is inevitable. Conventionally, prefilter synchronous reference frame-phase-locked loops exhibit excellent phase-lock ability at fixed frequency (50/60Hz), but become ill when frequency changes especially at zero frequency. In this article, a novel transformation matrix is derived to map the asymmetric phase-shift signals onto two-phase stationary coordinate system. Then, an arbitrary phase shift-phase-locked loop is formed by replacing Clark transformation with the proposed transformation matrix, which can accurately extract rotor position and speed information in a simple and effective way, avoiding the utilization of complex notch filter. Simulations in continuous domain based on MATLAB and experiments in discrete domain based on an 18-slot/20-pole prototyped PMSM both confirm the effectiveness of the proposed method.

A 3rd-Order FIR Filter Implementation Based on Time-Mode Signal Processing

Abstract: This paper presents the hardware implementation of a 3rd-order low-pass finite impulse response (FIR) filter based on time-mode signal processing circuits. The filter topology consists of a set of novel building blocks that perform the necessary functions in time-mode including z−1 operation, time addition and time multiplication. The proposed time-mode low-pass FIR filter was designed in a 28 nm Samsung fully-depleted silicon-on-insulator FD-SOI process under 1 V supply voltage with 5 MHz sampling frequency. Simulation results validate the theoretical analysis. The FIR filter achieves a signal-to-noise-plus-distortion ratio (SNDR) of 38.6 dB at the input frequency of 50 KHz consuming around 200 μW.

Tunable Bandstop Filter using Graphene in Terahertz Frequency Band

Abstract: In this paper, a planar graphene-based bandstop filter is designed and simulated for the resonant frequency of 1 THz. The transmission line model of the bandstop filter is considered, which consists of open-circuited shunt stubs that are interconnected through unit elements. The bandstop filter design is carried out from the normalized low pass Chebyshev prototype. By using frequency transformation, Richard’s transformation, and Kuroda’s identity, the desired bandstop filter can be designed from the low pass prototype. The graphene layer is introduced between the conductor layer and the dielectric for supporting the propagation of plasmonic waves. The simulation results show that the desired frequency response can be obtained for the designed graphene-based bandstop filter. By varying the chemical potential of the graphene layer, the resonant frequency of the bandstop filter can be tuned over the range of 0.1 THz with the constant absolute bandwidth.

A filter representation of diffraction at infinite and finite wedges.

Abstract: Diffraction of sound occurs at sound barriers, building and room corners in urban and indoor environments. Here, a unified parametric filter representation of the singly diffracted field at arbitrary wedges is suggested, connecting existing asymptotic and exact solutions in the framework of geometrical acoustics. Depending on the underlying asymptotic (high-frequency) solution, a combination of up to four half-order lowpass filters represents the diffracted field. Compact transfer function and impulse response expressions are proposed, providing errors below ±0.1 dB. To approximate the exact solution, a further asymptotic lowpass filter valid at low frequencies is suggested and combined with the high-frequency filter.

CMOS Compatible First-Order Current Mode Universal Filter Structure and its Possible Tunable Variant

Abstract: A novel first-order universal filter structure supporting current mode operation is proposed in this paper. The filter has a single active building block based realization and utilizes an extra-X second-generation current conveyor as an active building block. Additionally, the proposed circuit employs a grounded resistor and a grounded capacitor as passive components. The circuit has the ability to deliver the all-pass, high-pass, and low-pass functionalities simultaneously without meeting any passive components matching constraint. High output impedance and load insensitive outputs are other remarkable signal processing features offered by the proposed filter structure. Theoretical behavior of the proposed filter is described by presenting ideal, non-ideal, parasitic, and stability analyses. Additionally, the resistorless variant of the proposed filter is also shown to impart the tunability feature. Personal simulation program with integrated circuit emphasis (PSPICE) simulation results are presented to verify the theoretically described performance of the proposed universal filter. Complementary metal oxide semiconductor (CMOS) realization of extra-X second-generation current conveyor is utilized for the purpose of simulations, therefore, the filter is CMOS compatible.

A Power-Efficient Multichannel Low-Pass Filter Based on the Cascaded Multiple Accumulate Finite Impulse Response (CMFIR) Structure for Digital Image Processing

Abstract: Abstract The author offers a power-efficient multichannel low-pass filter for digital image processing based on the cascade multiple accumulate finite impulse response (CMFIR) structure in this study. The CMFIR filter was created using the outputs of a linear time-invariant system (LTI), which was built using a cascaded integrator comb (CIC) and a MAC low-pass filter. The sample rate convertor based on CIC filters effectively conducts decimation or interpolation. The sample rate convertor with the CIC filter can only accommodate narrowband transmissions and so cannot be utilized for wideband signals. The MAC architecture-based sample rate convertor is a good solution for high-bandwidth signals, but it uses more resources like registers and flip-flops, which increases power consumption. Here, the CMFIR low-pass filter acts as an interpolator, introducing a sample to boost the image's resolution. CMFIR is a useful tool for addressing the issue of aliasing during sampling. In addition, the genetic algorithm was used to increase the filter's resource utilization and power consumption efficiency.

Voltage mode and trans-admittance mode first-order universal filters employing DV-EXCCCII

Abstract: This paper reports a first-order voltage mode and trans-admittance mode universal filter from the same circuit structure. This configuration employs a single Differential Voltage Extra-X Current Controlled Current Conveyor (DV-EXCCCII) and one capacitor to realise a first-order Low Pass Filter (LPF), High Pass Filter (HPF), and All Pass Filter (APF) in voltage mode and trans-admittance mode. The DV-EXCCCII is an electronically tunable analog block, so the filter response can be varied with the bias current of the DV-EXCCCII. No matching constraints are necessary to realise the proposed filter. The sensitivity is found to be low because of passive components and also due to non-idealities. The reported circuit configuration is implemented through CADENCE VIRTUOSO and verified in SPECTRE using 0.18 µm UMC CMOS technology process parameters.

Inductanceless high order low frequency filters for medical applications

Abstract: In this paper, a designed circuit used for low-frequency filters is implemented and realized the filter is based on frequency-dependent negative resistance (FDNR) as an inductor simulator to substitute the traditional inductance, which is heavy and high cost due to the coil material manufacturing and size area. The simulator is based on an active operation amplifier or operation transconductance amplifier (OTA) that is easy to build in an integrated circuit with a minimum number of components. The third and higher-order Butterworth filter is simulated at low frequency for low pass filter to use in medical instruments and low-frequency applications. The designed circuit is compared with the traditional proportional integral controller enhanced (PIE) and T section ordinary filter. The results with magnitude and phase response were compared and an acceptable result is obtained. The filter can be used for general applications such as medical and other low-frequency filters needed.

Multibandwidth Repetitive Control Resisting Frequency Variation in Grid-Tied Inverters

Abstract: In this article, multibandwidth repetitive control (RC) is developed and applied to a grid-tied inverter to resist grid frequency variation. In the proposed RC, each of the resonant bandwidth is set individually by the gain of the internal model filter. A design procedure for the internal model filter is proposed, which splits the filter into several zero-phase finite impulse response (FIR) filters for reducing the design difficulties. The control structure and stability analysis show that the gain of the multibandwidth RC is increased. An example design procedure for the multibandwidth RC is presented in detail. Comparison experiments with different RCs are performed under deviated grid frequencies, and the results demonstrate the effectiveness of the proposed multibandwidth RC scheme.

A Comprehensive Investigation On the Selection of High-Pass Harmonic Filters

Abstract: In recent years, there is an increased use of passive filters in both transmission and distribution systems due to the proliferation of power electronic devices. However, the problem of filter design has not been well addressed in the past and one example is the application of high-pass filters in a filter package. Three types of HP filters are widely used to mitigate multiple harmonics, i.e., 2 ^nd HP filter, 3 ^rd HP filter and C-type filter. There is still a lack of research to clearly reveal the characteristics of each filter, which makes it difficult for the designer to select the optimal filter topology under different circumstances. The main goal of this paper is to solve the problem of how to select a proper configuration among three HP filter candidates for a given harmonic problem. Unlike the conventional optimization-based filter studies, this paper investigates three HP filters in an analytical way. As a result, the paper provides a deep insight into the inherent characteristics of the filter and the conclusions drawn in the paper are universal; thus can be used in different applications, ranging from low voltage levels to high voltage levels. The research results lead to a recommended application scope of each HP filter, which is very useful to guide the design of filter packages and help designers to evaluate the design results.

Designing low-pass filter in equivalent-input-disturbance compensator for improving disturbance-rejection performance.

Abstract: This paper presents a high-order low-pass filter for the equivalent-input-disturbance (EID) approach to improving the disturbance-rejection performance. The configuration characteristic of the presented filter clearly explains the reason why the disturbance-rejection performance is improved and provides a guideline to design it. Using the presented filter to replace the conventional filter derives a high-order EID (HEID) approach. It is easy to apply the small-gain theorem in deriving stability conditions of the HEID-based control system. Moreover, the presented filter is proved to be better than the conventional one. Finally, a comparison shows the validity and superiority of the presented method. And a simulation result shows that the HEID approach is easily extended in a multiple-input, multiple-output system even with effects of a white noise and parameter uncertainties.

Denoising electrocardiogram signals using multiband filter and its implementation on FPGA

Abstract: The electrocardiogram (ECG) signal carries vital information related to cardiac activities. While measuring ECG using electrodes, the signal is contaminated with powerline interference (PLI) from harmonics, baseline wandering (BW), motion artefacts (MA) and high frequency (HF) noise. The extraction of the ECG signal, without the loss of useful information from the noisy environment, is required. Therefore, the selection and implementation of an efficient filter design is proposed. The Finite Impulse Response (FIR)-based multiband needs separate digital filters, such as Lowpass, Highpass, and Bandstop Filter in cascade. The coefficients of the FIR multiband filter are optimised using a least squares optimisation method and realised in a direct form symmetrical structure. The capability of the proposed filter is evaluated on a Physionet ECG ID database, having records of inherent noisy ECG signals. The performance is also verified by measuring the power spectrum of the noisy and filtered ECG waveform. Also, the feasibility of the proposed multiband filter is investigated on Xilinx ISE and the design is implemented on a field programmable gate array (FPGA) platform. A low order simple multiband filter structure is designed and implemented on the reconfigurable FPGA device.

A Preliminary Step to Realize Digital Filter for Electrocardiogram Signal Denoising

Abstract: The electrocardiogram (ECG) is one of the most commonly used technique in the assessment of cardiovascular disease. Cardiovascular disease is one of the major cause of death in many countries so it is important for interpretation of heart beat. The ECG signal during its acquistion gets commonly affected by baseline drift that hinders physician in the correct diagnosis of heart condition. In this work, ECG signal is preprocessed to alleviate noise. Digital filters such as Infinite Impulse Response (IIR) and Finite Impulse Response (FIR) filter are designed for the purpose of removal of artifacts from the signal. The IIR Butterworth low pass filter and least square linear phase low pass FIR filter are designed to reduce the baseline drift artifact in ECG signal. The preprocessing block is designed in MATLAB filter design and analysis tool. The corresponding model is realized in simulink environment. The performance measures of IIR and FIR filter are analyzed. The corresponding HDL code is generated and is targeted to a field programmable gate array board to observe the simulation results.

Adaptive Extremum Seeking Control Based LCL Filter Resonant Frequency Online Estimation

Abstract: The LCL filter has been widely used in the grid-tied inverter systems. However, the resonance of the LCL filter can reduce the system stability margin and the control performance. Moreover, the grid impedance variations can lead to the drift of the resonant frequency, which can further worsen the system robustness. Thus, it is important to know the actual resonant frequency of the LCL filter. In this letter, an adaptive extremum seeking control (AESC) based estimation scheme is proposed to estimate the resonant frequency of the LCL filter online. By injecting a high-frequency (HF) signal into the inverter output voltage, the AESC scheme can identify the extremum of the LCL filter amplitude response, i.e., resonant peak. The amplitude of injection signal is adaptive based on the inverter HF response, which can address the tradeoff between the dynamic response and inverter output current quality. Most importantly, compare to other method, the proposed scheme has very low computational complexity, which minimizes the burden to the normal inverter controller operation. Stability analysis is given in this letter, and experimental studies are conducted to validate the effectiveness of the proposed scheme.

A variable bandwidth memristor‐based Legendre Optimum low pass filter for radio frequency applications

Abstract: This article presents the enhancement of Legendre Optimum low pass filter (LPF) in terms of reusability and bandwidth, based on the programmable memristance of memristors. Two LPFs of the third order, operating in the MF and VHF range, and designed using the insertion loss method are presented. At 600 kHz and 110 MHz, two Knowm memristors working in the forward ion‐conduction mode replace Rs and RL in the filter circuit. Their conductance and therefore memristance is varied such that Roff−Ron decreases monotonically and /Roff−Ron/>0 . Results show a bandwidth enhancement of up to 540 at 600 kHz, and up to 100 at 110 MHz. A reusable, cost‐effective, variable bandwidth filter is achieved from the original fixed bandwidth filter.

A SiGe HBT 6th-Order 10 GHz Inductor-Less Anti-Aliasing Low-Pass Filter for High-Speed ATI Digitizers

Abstract: High-speed digitizers operating at sampling rates higher than 10GS/s require low-pass anti-aliasing filters in the multi-GHz range. Asynchronous Time-Interleaved (ATI) digitizers also need low-pass filters before digitization, and additional requirements on their design are set by this specific application. In integrated solutions, inductor-less filters are important for minimizing the chip area footprint. In this paper, we present the design of a 6^th-order inductor-less 10GHz low-pass filter implemented in the STMicroelectronics SiGe BiCMOS55 process. It can be used as anti-aliasing filter for conventional 30GS/s digitizers or at the output of a 40GS/s ATI digitizer. We exploit positive feedback to synthesize the active inductor based on a stacked topology, minimizing the number of current branches, and thus power consumption. Analysis and design guidelines for the biquad are presented. The filter exhibits a bandwidth of 10GHz with a power consumption of 43mW, a THD of −45dB and an SNR of 43dB with an input amplitude of 710mV peak-to-peak differential. Extensive corner and Monte Carlo post-layout simulations have been carried out to highlight the robustness of the circuit to PVT and mismatch variations. Experimental results have confirmed very good agreement between measured and simulated performance, validating the proposed design flow.

Virtual Flux Voltage-Oriented Vector Control Method of Wide Frequency Active Rectifiers Based on Dual Low-Pass Filter

Abstract: This article presents a non-AC-side voltage sensor control method applied to More Electric Aircraft rectifiers. The control strategy can operate properly over a wide range of frequencies. This strategy calculates the AC supply frequency through an instantaneous phase-locked loop and feeds it back to a dual low-pass filter. The reconstructed rectifier-side voltage is filtered using two low-pass filters with different scale factors. Then, the values of the two filter outputs are subtracted and the effect of the DC bias due to the initial value of the integration is eliminated. The subtracted value is amplitude-phase compensated to calculate the virtual flux value. The phase angle can then be calculated from the virtual flux value. This phase angle is used for the implementation of the voltage-oriented vector control and as an input to the instantaneous phase-locked loop. Simulation and experimental results show that the use of dual low-pass filters under different frequency conditions improves the speed and accuracy of virtual flux estimation and eliminates DC-side bias errors.

The Design and Simulation of a Fifth-order Chebyshev Low-Pass Filter

Abstract: Chebyshev filter is a design classification of filters. It uses the Chebyshev transfer function, and has many filter types, such as high-pass, low-pass, band-pass, high-resistance, band-stop and so on. Compared with the Butterworth filter, the transition band of the Chebyshev filter is very narrow, but the internal amplitude-frequency characteristics are unstable [1][2]. Chebyshev filter achieves complex transmission zeros to improve the group delay characteristics in the pass band and reduce the signal distortion. In the process of designing a five-order Chebyshev filter, an active filter network needs to be established, and each stage of the low-pass filter composed of an amplifier is connected in the same cascade to form a multi-order Chebyshev low-pass filter. To design a Chebyshev filter, a Sallen-key structure is needed, and the transfer function is determined according to the position and size of the different resistors and capacitors placed, and a Chebyshev filter with different functions is constructed. The Multisim Simulation software is used to simulate the design results, and the frequency response amplitude curve in the image is found to be fluctuating with equal ripple in the pass or stop band.

Synthesis of High-Input Impedance Electronically Tunable Voltage-Mode Second-Order Low-Pass, Band-Pass, and High-Pass Filters Based on LT1228 Integrated Circuits

Abstract: This paper introduces two new high-input impedance electronically tunable voltage-mode (VM) multifunction second-order architectures with band-pass (BP), low-pass (LP), and high-pass (HP) filters. Both proposed architectures have one input and five outputs, implemented employing three commercial LT1228 integrated circuits (ICs), two grounded capacitors, and five resistors. Both proposed architectures also feature one high-impedance input port and three low-impedance output ports for easy connection to other VM configurations without the need for VM buffers. The two proposed VM LT1228-based second-order multifunction filters simultaneously provide BP, LP, and HP filter transfer functions at Vo1, Vo2, and Vo3 output terminals. The pole angular frequencies and the quality factors of the two proposed VM LT1228-based second-order multifunction filters can be electronically and orthogonally adjusted by the bias currents from their corresponding commercial LT1228 ICs, and can be independently adjusted in special cases. In addition, both proposed VM LT1228-based second-order multifunction filters have two independent gain-controlled BP and LP filter transfer functions at Vo4 and Vo5 output terminals, respectively. Based on the three commercial LT1228 ICs and several passive components, simulations and experimental measurements are provided to verify the theoretical predictions and demonstrate the performance of the two proposed high-input impedance electronically tunable VM LT1228-based second-order multifunction filters. The measured input 1-dB power gain compression point (P1dB), third-order IMD (IMD3), third-order intercept (TOI) point, and spurious-free dynamic range (SFDR) of the first proposed filter were −7.1 dBm, −48.84 dBc, 4.133 dBm, and 45.02 dBc, respectively. The measured input P1dB, IMD3, TOI, and SFDR of the second proposed filter were −7 dBm, −49.65 dBc, 4.316 dBm, and 45.88 dBc, respectively. Both proposed filters use a topology synthesis method based on the VM second-order non-inverting/inverting HP filter transfer functions to generate the BP, LP and HP filter transfer functions simultaneously, making them suitable for applications in three-way crossover networks.