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The local fractional derivative (LFD) has attracted wide attention in the field of engineering application. In this paper, the LFD is used to model the fractional Sallen-Key filter for the first time. The non-differentiable(ND) transfer function is obtained by using the local fractional Laplace transform(LFLT). And the amplitude frequency response is analyzed in detail for different fractional order ς. It is found that the fractional Sallen-Key filter becomes the ordinary one in the special case ς = 1. The obtained results of this paper show the powerful ability of local fractional calculus in the analysis of complex problems arising in engineering fields.

For fault diagnosis of nonlinear analog circuit, a novel method based on generalized frequency response function (GFRF) and least square support vector machine (LSSVM) classifier fusion is presented. The sinusoidal signal is used as the input of analog circuit, and then, the generalized frequency response functions are estimated directly by the time-domain formulations. The discrete Fourier transform of measurement data is avoided. After obtaining the generalized frequency response functions, the amplitudes of the GFRFs are chosen as the fault feature parameters. A classifier fusion algorithm based on least square support vector machine (LSSVM) is used for fault identification. Two LSSVM multifault classifiers with different kernel functions are constructed as subclassifiers. Fault diagnosis experiments of resistor-capacitance (RC) circuit and Sallen Key filter are carried out, respectively. The results show that the estimated GFRFs of the circuit are accurate, and the fault diagnosis method can get high recognition rate.

In this paper, a new voltage-mode all-pass filter topology based on single current operational amplifier (COA) and the implementation of COA by using current conveyors are presented. The proposed topology employs three admittances and single active circuit element. COA implementation by using current conveyor blocks as sub-circuit contributes to workability of the COA employing circuits by using commercially available integrated circuits that can be employed as current conveyor. The validity of the proposed filter is verified by PSPICE simulation programme by using the MOSIS 0.35 micron CMOS process parameters. The simulation results agree well with the theoretical analysis and the circuit achieve a good total harmonic distortion (THD) performance.

In this paper, a voltage mode multifunction filter based on single voltage differencing differential difference amplifier (VDDDA) is presented. The proposed filter with three input voltages and single output voltage is constructed with single VDDDA, two capacitors and two resistors. Its quality factor can be adjusted without affecting natural frequency. Also, the natural frequency can be electronically tuned via adjusting of bias current. The filter can offer five output responses, high-pas (HP), band-pass (BP), band-reject (BR), low-pass (LP) and all-ass (AP) functions in the same circuit topology. The output response can be selected by choosing the suitable input voltage without the component matching condition and the requirement of additional double gain voltage amplifier. PSpice simulation results to confirm an operation of the proposed filter correspond to the theory.

Sallen-Key filters are widespread in audio circuits. Therefore, accurate and efficient digital models of such filters are highly desirable in audio Virtual Analog applications. In this paper, we will discuss a possible strategy, based on Wave Digital Filters (WDFs), for implementing all the analog filters described in the historical 1955 manuscript by Sallen and Key. In particular, we will group the eighteen filter models presented by Sallen and Key into nine classes, according to their topological properties. For each class we will describe the corresponding WDF structures. Finally, we will compare the output signals of WDFs to the output signals of the same models implemented in LTSpice.

In this brief, a 28.8-MHz −3-dB frequency low-pass analog filter is presented. The filter synthesizes a fourth-order Butterworth transfer function, exploiting the well-known Sallen-Key (SK) biquadratic cell. The out-of-band zeros typically present in SK implementations are hereby completely canceled by using a low-power auxiliary path. This leads to a significant improvement of the stop-band rejection, at the cost of a small power for the same auxiliary path biasing. The design exhibits very large in-band IIP3 over the entire filter bandwidth (20 dBm at 10 MHz and 11 MHz), at 3.2-mW power consumption. The filter prototype has been designed in CMOS 0.18- $ {\mu }\text{m}$ technological node. The total area occupancy is 0.12 mm $^{ {2}}$ and the in-band integrated noise is $101~ {\mu }{\mathrm{V}}_{\mathrm{RMS}}$ .

This paper presents possible solution of fractional-order high-pass filter (FHPF) with electronically adjustable order between 1 and 2 and also with electronically adjustable pole frequency. It is based on well-known Follow-the-Leader Feedback (FLF) topology adjusted for utilization with operational transconductance amplifiers (OTAs) and adjustable current amplifiers (ACAs). This 3rd-order topology is used in order to approximate FHPF response in particular frequency band of interest. Design is supported by Pspice simulations for three particular values of the filter's order (1.25, 1.5, 1.75) and for several values of pole frequency. Moreover, simulation results with two different approximations are compared.

Piezoelectrically actuated flapping-wing micro air vehicle (MAV) is an emerging technology. This paper discusses limitations of presently used voltage drivers for the piezoelectric actuators used in such applications and suggests an active filter-based unipolar high-voltage driver. A Chebyshev polynomial has been used to extract a unipolar sinusoidal high voltage signal from a unipolar square wave signal for driving the piezoelectric actuators at low frequency in flapping-wing MAV applications. The filter is based on Sallen–Key topology and is suitable for connecting a piezo-bimorph in series or parallel electrical connection. We have considered an application-specific piezoelectric bimorph actuator of 40 Hz flapping frequency and 32 nF capacitance in each piezoelectric layer to design a driver. The driver circuit in verified by simulation results of OrCAD® software. The driver circuit can control the frequency of the sinusoidal driving voltage, which causes wing-flapping, by radio control communication.

In this paper, a new synthesis method for parallelcoupled line bandpass filter is presented. Design formulas are derived for a third-order bandpass filter with arbitrary coupledline image impedance. These formulas are more accurate than the conventional method to address the prediction bandwidth. Third-order parallel-coupled bandpass filters are designed and simulated to validate the theory.

A power-efficient frequency compensation topology for three-stage transconductance amplifiers is presented in this paper. Stability analysis and design equations are carried out based on the small-signal model. Unlike many recently reported solutions, the proposed architecture do not rely upon parasitic and/or pole-zero cancellation, thus providing a more robust design. As an example, the proposed technique was used to design a three-stage amplifier in a standard CMOS 65-nm technology. The amplifier achieves a 2-MHz gain-bandwidth product when driving a 1-nF capacitance by consuming only 82 μW from a 2.5-V supply. Simulation results are found in good agreement with theoretical analysis and show an improvement in both small-signal and large-signal amplifier performance over previously reported solutions.

International audience; In this paper, we present a bandpass filter designed and implemented in 65-nm CMOS. From 0.8-2.2GHz filtering requirements are very challenging. This filter is dedicated to fully digital RF Tx cellular architectures, and is available for any Tx architecture. Our filter uses highly linear CMOS active inductors that exhibit Q factors above 1000 at cellular frequencies to reduce filter insertion losses. The highly linear characteristic of implemented active inductors drive it us to 0dBm operation while providing at least 24dB attenuation at ± 400MHz from F0. Measurement results of the filter show a central frequency (F0) of 1.8GHz with 135MHz of -3dB bandwidth (BW) with less than 0.1dB IL

Comunicación presentada al "V VLSI Circuits and Systems" celebrado en Praga (República Checa) el 18 de Abril del 2011., A fully differential programmable gain amplifier (PGA) with constant transfer characteristic and very low power consumption is proposed and implemented in a 130 nm CMOS technology. The PGA features a gain range of 4 dB to 55 dB with a step size of 6 dB and a constant bandwidth of 10-550 kHz. It employs two stages of variable amplification with an intermediate 2nd order low-pass channel filter. The first stage is a capacitive feedback OTA using current-reuse achieving a low input noise density of 16.7 nV/√Hz. This stage sets the overall high-pass cutoff frequency to approximately 10 kHz. For all gain settings the high-pass cutoff frequency variation is within ±5%. The low-pass channel filter is merged with a second amplifying stage forming a Sallen-Key structure. In order to maintain a constant transfer characteristic versus gain, the Sallen-Key feedback is taken from different taps of the load resistance. Using this new approach, the low-pass cutoff frequency stays between 440 kHz and 590 kHz for all gain settings (±14%). Finally, an offset cancelation loop reduces the output offset of the PGA to less than 5 mV (3σ). The PGA occupies an area of approximately 0.06 mm2 and achieves a post-layout power consumption of 55 μW from a 1V-supply. For the maximum gain setting the integrated input referred noise is 14.4 μVRMS while the total harmonic distortion is 0.7 % for a differential output amplitude of 0.5 V., This work has been supported by the Spanish Ministry of Science and Innovation under grant TEC2009-08447, the Junta de Andalucía under grant TIC-02818 and the 2007-2013 FEDER Program.

In this paper, a miniaturized UWB bandpass filter using a hybrid lumped capacitors-distributed transmission lines topology is designed. The filter design rules are carried out and a filter is optimized for a 3 dB fractional bandwidth of 127 % with criteria of compacity, matching and selectivity. A sensitivity study versus critical parameters is also given. The filter length is reduced to 0.18lambda @ 6.5 GHz in comparison with 0.54lambda for the distributed topology. The selectivity is improved with a shape factor equal to 1.28:1 instead of 1.46:1

In this paper, a frequency analysis of a voltage feedback amplifier based on second generation current conveyors with inductive input/output impedance, is presented. The traditional voltage amplifier configured from voltage and current feedback operational amplifiers are studies and compared. PSPICE simulation confirms the theoretical approach.

A novel current-mode active filter topology using a first generation current conveyor (CCI) and an operational transconductance amplifier (OTA) is presented. Using this topology, grounded-capacitor biquadratic bandpass and lowpass filter sections, with at most five one-port passive elements, are realized. In these realizations, the parameterω0can be adjusted without disturbing the parameterω0/ Q0

A second-order bandpass filter using one of Antoniou's gyrator is discussed, which is found to be little affected by the nonidealities and the nonlinearity of the operational amplifiers, and seems to be ideally suited for high-Q and high-frequency applications. A model to study the effects of slew-rate on the filter is proposed, which can be applied to any circuit configuration, involving any number of operational amplifiers. Copyright ? 1981 by The Institute of Electrical and Electronics Engineers, Inc.

The paper describes a simple high-Q insensitive active band-pass filter having relatively few passive components and active elements with low closed-loop gains, using positive feedback Q enhancement scheme. The proposed filter has minimum dependence on the bandwidth of the operational amplifiers and is capable of operating over a wide frequency range with relatively stable Q and resonant frequency.

A bandpass filter using only two registors and two operational amplifiers is suggested. The circuit has a Q equal to the ratio of the resistors. While Q and gain are insensitive to temperature variations, the variations in center frequency is minimized using a compensation scheme. Copyright ? 1974 by The Institute of Electrical and Electronics Engineers, Inc.

A double-integrator active-RC filter is described, in which both Q and frequency sensitivity to the operational-amplifier Gain-bandwidth product are made zero by active-compensation techniques. The circuit can be used for high-Q high-frequency applications. Copyright ? 1977 by The Institute of Electrical and Electronics Engineers, Inc.

The pole of an operational amplifier and a grounded capacitor are used for obtaining a high Q bandpass function. The utilization of the pole of the operational amplifier enables the extension of its useful frequency range. The gain and the bandwidth of the operational amplifier are the primary factors determining the filter performance. The experimental results of a low-sensitivity filter circuit are presented. The circuit is suitable for integration. Copyright 1973 by The Institute of Electrical and Electronics Engineers, Inc.