Biquad Filter Research Articles

Analog Circuit Soft Fault Diagnosis Based on Sparse Random Projections and K-Nearest Neighbor

Analog circuit fault diagnosis is a key problem in theory of circuit networks and has been investigated by many researchers in recent years. An approach based on sparse random projections (SRPs) and K-nearest neighbor (KNN) to the realization of analog circuit soft fault diagnosis has been presented in this paper. The proposed method uses the wavelet packet energy spectrum and sparse random projections to preprocess the time response for feature extraction. Then, the variables of the fault features are constructed, which are used to form the observation sequences of K-nearest neighbor classifier. K-nearest neighbor classifier is used to accomplish the fault diagnosis of analog circuit. In this paper, four-opamp biquad high-pass filter has been used as simulation example to verify the effectiveness of the proposed method. The simulations show that the proposed method offers higher correct fault location rate in analog circuit soft fault diagnosis application as compared with the other methods.

Realization of SIMO biquad filters and quadrature sinusoidal oscillators using OTRAs

In this communication, two single-input multiple-output (SIMO) type biquad filters employing operational transresistance amplifiers (OTRAs) have been presented. Various parameters of the proposed filter circuits viz. pole frequency (ɷ), pole quality factor (Q) and the gain are independently controllable. The proposed filter configurations can also be converted into low frequency oscillators with fully uncoupled control of condition of oscillation and frequency of oscillation with quadrature output voltages. The active and passive sensitivities of the proposed circuits have been found to be small. SPICE simulation results and experimental validation of the proposed circuits employing OTRAs realized with AD844 type CFOAs have also been presented.

MOSFET-C current mode filter for secure communication applications

In this paper, a dual output current-mode biquad filter with band-pass and low-pass outputs using MOS transistors and capacitors is presented. In these type of filters MOSFETs operating in saturation mode are used instead of standard active elements and transconductances of these transistors are utilized instead of resistors. In the study a voltage controlled current source (VCCS) based core filter circuit is presented. This circuit is used as a starting point for the complete filter design. After VCCSs are replaced by MOSFETs biased for operating in saturation region, a resistorless MOSFET-C type filter circuit is obtained with only seven transistors and two grounded capacitors. Also, an agile filter application for secure communication is given to illustrate the functionality.

Voltage-Mode Biquad Filter Using Four OTAs and Its Application in Quadrature Oscillator with Noninteractive Control of the Oscillation Condition and Frequency

This paper presents an independently tunable, four-input, three-output, voltage-mode (VM) biquad filter consisting of four operational transconductance amplifiers (OTAs) and two grounded capacitors. The proposed circuit can simultaneously realize three basic biquad filtering functions for single input and three outputs. All five standard biquad filtering functions can be implemented with four inputs and single output by appropriate application of input voltage signals. The developed biquad filter with high input impedances enables noninteractive control of natural angular frequency and quality factor. By slightly modifying the proposed biquad filter, the VM quadrature sinusoidal oscillator with noninteractive control for the oscillation condition and the oscillation frequency has been achieved. Simulation and experimental results are used to validate theoretical predictions.

Cascade biquad controller design for feedforward active noise control headphones considering incident noise from multiple directions

Active noise control headphones have become one of the most popular wearable personal devices currently. In this paper, the feedforward controller design problem using cascade biquad filters is addressed with respect to multiple incident directions of the primary noise. Criterion functions evaluating the comprehensive noise reduction performance are given, and the optimization methods for both single-channel and multi-channel controllers are proposed where Differential Evolution algorithm is used to find the global minimum. Experiments based on a commercial headphone are carried out and the results have validated the proposed methods. It has been shown that the comprehensive performance under multiple directions would be significantly improved when multiple reference microphones are used along with a multi-channel control strategy.

Electronically Tunable SIMO type Mixed-mode Biquadratic Filter using Single FTFNTA

In this manuscript, a new electronically tunable single input multiple output (SIMO) type mixed-mode biquad filter is proposed. It comprises of single Four Terminal Floating Nullor Transconductance Amplifier (FTFNTA) as an Active Building Block, one resistor, and two grounded capacitors. The proposed design can generate current mode (low-pass, high-pass, and band-pass) filters and transimpedance mode (band-pass and inverting low-pass) filters simultaneously for current as an input. Similarly, for voltage as input, it can generate voltage mode (high-pass and inverting band-pass) filters and transadmitance mode (inverting band-pass and inverting high-pass) filters simultaneously. The pole frequency (ω 0 ) and quality factor (Q 0 ) can be tuned electronically as well as through a grounded capacitor without disturbing the bandwidth (ω 0 /Q 0 ). Design is independent from the input as well as passive component matching constraint. The presence of grounded capacitors makes the circuit feasible for IC realization. The functionality of the proposed design is validated through PSIPCE simulation. To check the robustness of the proposed design Monte Carlo, sensitivity, and noise analysis is also performed.

A class-AB linear transconductor with enhanced linearity

In this paper a novel linear transconductor topology is proposed, where class-AB behavior based on adaptive biasing is exploited to improve the linear range. The adaptive biasing circuit is based on the Winner-Take-All topology already used for class-AB OTAs, and optimized to improve the linearity, and the proposed transconductor features a gain control input for tunability. The transconductor provides a gain of 43 μS while consuming 70 μW. The linear range (1% variation of the dc transconductance gain) is 470 mVpp, about 4.5 times larger than for the corresponding class-A cell. Total harmonic distortion is improved by about 15 dB, and good results in terms of linearity and noise are reported with respect to the state-of-the-art. Simulations of a Gm-C biquad filter based on the proposed transconductor are also reported to validate the design.

Power Efficient Biquadratic Filter designing using OTA

Objectives: To present a power efficient Universal Biquad Operational Transconductance Amplifier circuit. Methods: OTA (operational transconductance amplifier) based Biquad filter is analyzed using three different simulated tools three different tools (CADENCE, XILINX, ORCAD and MATLAB tools) are used for designing the circuit. The 0.18mm CMOS technique is used using the Cadence tool for plan and reproduction. The same circuit has been implemented on ORCAD tool as well as Xilinx tool. Findings: The proposed Biquad filter improves the frequency response, power dissipation and provides vary of the KHN biquadratic filter circuits it uses minimum numbers of Operational Transconductance phenomenon Amplifier (OTA) to realize an equivalent. The assorted parameters specifically Center frequency, dcgain, Bandwidth, Power Dissipation and Quality issue are all electronically tunable. OTA based Biquad filter is simulated in CADENCE Virtuoso tool. Opamp-RC Biquad filter offers a bandwidth of 425 kHz, pass band gain of zero DB, whereas Gm-C measuring system based mostly filter offers 85MHz, passband gain of zero DB. Over-all power dissipation of the Biquad filter is 4.3mW with 1.8V DC Supply has basing current of 50mA with gracefully voltage 2.5v. by keeping the supply voltage, bias current and load capacitor as 2.5V, 50mA and 10pFrespectively, it has been seen that the power is reduced using the CADENCE virtuoso tool. Novelty : This study presents a Universal Biquadratic filter having less power dissipation. The circuit was optimized for gain, GBP, slew rate, areas, voltage offset, phase margin, power area etc. compared to all the previous filter circuits (OTA GMC filters, OTA type-C filters) designed with the help of OTA. Keywords: OTA; CMOS; CADENCE Virtuoso; Static Power; Dynamic Power; MOSFET

One input voltage and three output voltage universal biquad filters with orthogonal tune of frequency and bandwidth

This research paper contributes the one input three output voltage mode universal biquad filters with linear and electronic control of the natural frequency (<em>w<sub>0</sub></em>), using two commercially available ICs, LT1228s as active device with two grounded capacitors, five resistors. The presented universal biquad filters can simultaneously provide three voltage-mode filtering functions, low-pass (LP), high-pass (HP) and band-pass (BP) without changing the circuit architecture. Furthermore, the first presented biquad filter provides low impedance at HP, BP voltage output nodes and LP, BP output voltage nodes are low impedance for the second proposed filter which is easy cascade ability with other voltage mode circuits without the employment of buffer circuits. The quality factor (<em>Q</em>) of both proposed filters is orthogonally adjusted from the passband voltage gain and <em>w<sub>0</sub></em>. The proposed filters are simulated and experimented with commercially accessible ICs, LT1228. The simulated and experimental results demonstrate the filtering performances.

Distributed switched-resistor approach for high-Q biquad filters

The switched-resistor (S-R) approach is becoming more and more popular among integrated circuits designers because it allows the implementation of very high equivalent resistances in CMOS circuits. When using this technique, the value of a reference poly resistor is multiplied by a factor dependent on the duty cycle of the clock signal. To achieve resistance multiplication factors higher than 100, the value of the duty cycle has to be reduced below 0.01, but in this case the effects of parasitic components are not negligible anymore and the value of the equivalent resistance tends to saturate at a maximum value. In this paper, we present a distributed switched-resistor approach that aims to strongly mitigate the effect of parasitic capacitances on the value of the equivalent resistance even when exploiting very small values for the duty cycle, thus allowing resistance multiplication factors up to a few thousands. As a validation of this approach, we consider the implementation of a high Q biquad filter for neural recording applications and compare the conventional S-R technique against the proposed distributed S-R approach in terms of the maximum achievable Q factor.

SIFO–VM/TIM universal biquad filter using single DVCCTA with fully CMOS realization

SIFO–VM/TIM universal biquad filter using single DVCCTA with fully CMOS realization

A novel memristor emulator design and universal biquad filter application using second generation high swing differential current conveyor transconductance amplifier in 130 nm CMOS process

Memristors have drawn a significant wide spread attention from the research community since past decade due to their high-speed operational potential in analog applications. However, it has been difficult to achieve the memristor behavior directly from solid state solution and state of the art. This work presents a novel emulator design to mimic the memristor behavior. A generic and simple emulator circuit for a voltage controlled memristor is presented using a differential difference current conveyor transconductance amplifier (DDCCTA), which is based on a versatile second-generation current conveyor methodology. A high-swing (up to ±600 mA at the output) and low power implementation design effort for DDCCTA is kept in 130 nm RF-CMOS process with dual power supply mode. The functional simulations have been performed in SPICE environment using Advanced Design System (Keysight Technology), which showed a good alignment to the memristor emulator’s I-V characteristic at 1 KHz and 10 KHz. Proposed DDCCTA then implements the memristor operation with compatible specifications. Finally, the memristor operation and potential has been verified by its application in high-speed active filter operations. A universal biquad section has been presented which employs the designed memristor emulator, with 30 mW of power dissipation with ±1.5 V supply.

CMOS Realization of Fully Electronically Tunable Single Resistance Control Mixed Mode Biquad Filter Employing Single VDTA at ± 0.6V

This paper presents a single VDTA based Mixed Mode type Biquad filter. The proposed Transadmittance Mode (TAM) type Biquad filter configuration employed single voltage differencing transconductance amplifier (VDTA) as an active building block, three passive element namely one grounded resistor, one grounded capacitor and one floating capacitor. The proposed transadmittance Mode multifunction Biquad filter configuration is presenting transadmittance mode type four basic standard filter functions low pass, high pass, band pass, band reject or band stop or band eliminate filter responses. These four type filter responses are realizing simultaneously with the selection of single input voltage signal. The proposed Transadmittance Mode multifunction Biquad filter configuration has more advantageous features such as low active and passive sensitivities, low power supply voltage, low power consumption, low quality factor, very low power consumption, more electronic tunability, higher linearity and required small area of the chip. The performance of the proposed configuration has been verified through PSPICE simulation using 0.18μm CMOS Technology process parameters.

An optimization framework for designing robust cascade biquad feedback controllers on active noise cancellation headphones

This work proposes an efficient and effective method to design the fixed feedback controller directly on active noise cancellation headphones by using the measured frequency response of the secondary path. The designed controller comprises several biquad filters whose parameters can be solved by a two-stage optimization strategy composed of the genetic algorithm and the simplex method. The construction of the loss function for this optimization follows the traditional H2/H∞ method, which takes noise reduction, waterbed effect, and robustness all into consideration. Simulation and experimental results show that the controller optimized by the proposed method can achieve good noise reduction performance with acceptable waterbed lifting while ensuring robustness to plant variations.

Voltage Differencing Current Conveyor Based Voltage-Mode and Current-Mode Universal Biquad Filters with Electronic Tuning Facility

The objective of this study is to present four new universal biquad filters, two voltage-mode multi-input-single-output (MISO), and two current-mode single-input-multi-output (SIMO). The filters employ one voltage differencing current conveyor (VDCC) as an active element and two capacitors along with two resistors as passive elements. All the five filter responses, i.e., high-pass, low-pass, band-pass, band-stop, and all-pass responses, are obtained from the same circuit topology. Moreover, the pole frequency and quality factor are independently tunable. Additionally, they do not require any double/inverted input signals for response realization. Furthermore, they enjoy low active and passive sensitivities. Various regular analyses support the design ideas. The functionality of the presented filters are tested by PSPICE simulations using TSMC 0.18 µm technology parameters with ± 0.9 V supply voltage. The circuits are also justified experimentally by creating the VDCC block using commercially available OPA860 ICs. The experimental and simulation results agree well with the theoretically predicted results.

Electronically tunable CFTA based positive and negative grounded capacitance multipliers

This paper presents four novel lossless grounded capacitance multiplier (GCM) circuits based on Current Follower Transconductance Amplifier (CFTA). Two of the proposed GCMs are positive and two are negative. The proposed GCMs include two CFTAs, two resistors, and a capacitor. The proposed GCMs employ a minimum number of passive components and do not require any passive element matching condition. The multiplication factor can be controlled either by bias current or by varying either of the two resistances. The effects of parasitic elements on the operating frequency range of the proposed GCMs have been investigated through mathematical analysis. Time and frequency domain analysis has been performed with LTspice program using 0.13 µm IBM CMOS technology parameters. The capacitance cancellation circuit and current-mode universal biquad filter applications are provided to demonstrate the usefulness of the circuit. Monte Carlo and temperature analyses have been performed to verify the robustness of the proposed GCMs. Additionally, comparison of the proposed GCMs with the relevant circuits previously reported in the literature is presented. An experimental example is provided to verify the time-domain performance of the proposed positive lossless GCM by using commercially available integrated circuits (ICs).

A Modified Bi-Quad Filter Tuning Strategy for Mechanical Resonance Suppression in Industrial Servo Drive Systems

For mechanical resonance suppression, the bi-quad filter is a powerful tool and has been widely used in industrial applications. Compared with the notch filter, the bi-quad filter has one more parameter for notch depth design, which is more suitable for servo systems with nature damping coefficients and limited resonant gains. Usually, the bi-quad filter tuning has three steps, including identification, discretization, and switching process. However, in industrial applications, these three steps still have room for improvement. In this article, three targeted modification methods are proposed. First, an identification method based on the twins-point search is proposed to find out all of the available potential elastic characteristics accurately and quickly, and get the resonant frequency, the rejection bandwidth, and the notch depth for filter design. Then, inspired by the discretization distortion correction of the notch filter, a parameter mapping Tustin method is used to achieve accurate discretization. Furthermore, considering the bi-quad filter's settling time, a “warm-up” buffer strategy prior to the filter switch-on is proposed to smooth the switching process. In the end, the validity and effectiveness of the proposed modification strategies are verified by experimental results.

New Gm-C All-pass and Amplitude-Equalizer Biquad

In this paper, new Gm-C all-pass and amplitude-equalizer biquads are shown to be realized from a generalized Gm-C biquad filter structure by using Gm-simulated negative resistor in series with integrating capacitor in the lossless integrator. The non-ideality analysis of the all-pass/ amplitude-equalizer biquad using finite output conductance and parasitic output capacitance of Gm-cells is presented. The proposed Gm-C all-pass and amplitude-equalizer biquads are simulated for 0.18 μm CMOS technology with ± 0.9 V power supply in Cadence environment to validate the frequency response characteristics. For the Gm-C AP biquad filter designed for 1 MHz cut-off frequency and pole quality factor of 2, the power consumption is 82.37 µW, the input-referred noise is 137.6 and the dynamic range is 62.84 dB. The biquad has the figure of merit (FoM) of 0.2969 × 10−13 J.

Synthesis of biquad filters using two VD-DIBAs with independent control of quality factor and natural frequency

This contribution presents the procedure to synthesis the voltage-mode active biquad filters using the active elements, voltage differencing differential input buffered amplifier (VD-DIBA). Two filtering categories, single input four output (SIFO) configuration and three input three output (TITO) configuration are proposed. Both proposed filters consist of two VD-DIBAs, two grounded capacitors and two resistors. All input voltage nodes for both biquad filters exhibit high impedance. The proposed SIFO biquad filter simultaneously provide four filtering responses, low pass (LP), band pass (BP), high pass (HP) and band reject (BR) functions, while the proposed TITO filter provides five filtering responses (including all pass (AP) function). The natural frequency (ω0) is linearly and electronically tuned without affecting the quality factor (Q). Also, the Q adjusting can be done without affecting the ω0. By modifying the proposed TITO biquad filter, the current controlled sinusoidal oscillator is achieved. The frequency of the generated sinewave is linearly tuned without affecting the condition of oscillation. The performances of the proposed circuits are simulated by Cadence software and the Spectre simulator of the Analog Design Environment using CMOS VD-DIBA in 0.18 μm TSMC CMOS technology and laboratory experiment using VD-DIBA constructed from commercially available ICs.

High-Input Impedance Voltage-Mode Multifunction Filter

This paper proposes a high-input impedance voltage-mode (VM) multifunction biquad filter which employs three current-feedback amplifiers (CFAs), three resistors, and two grounded capacitors. The proposed VM multifunction biquad filter has single-input and triple-output and can realize non-inverting low-pass (NLP), inverting band-pass (IBP), and non-inverting band-stop (NBS) voltage responses at the same time without increasing component selection. The proposed VM multifunction biquad filter enjoys the orthogonal tunability of angular frequency and quality factor and also provides the advantage of using only two grounded capacitors, high-input impedance and low active/passive sensitivity. The performance of the proposed VM multifunction biquad filter is verified through its hardware implementation and OrCAD PSpice simulation based on AD844-type CFAs. The circuit analysis, sensitivity analysis, and NLP, IBP, and NBS voltage responses are also shown in this paper. The paper presents a method to effectively reduce the active and passive components, maintain good circuit performance, and reduce circuit costs.