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In this study, electronically-tunable, current-mode, square-root-domain, third-order low-pass filter is proposed. The study is carried out with three circuit designs. First circuit is third-order low-pass Butterworth filter, second circuit is third-order low-pass Chebyshev filter and the last circuit is third-order low-pass elliptic filter. All the input and output values of the filter circuit are current. Only grounded capacitors and MOSFETs are required in order to realize the filter circuit. Additionally, natural frequency of the current-mode filter can be adjusted electronically using outer current sources. To validate the theory and to demonstrate the performance of third-order filter, frequency and time domain simulations of PSPICE program are used. To that end, TSMC 0.35m Level 3 CMOS process parameters are utilized to realize the simulations of the filter. [ABSTRACT FROM AUTHOR]

In this paper, an adaptive N-path filter design technique is presented. The filter designed by this method can be reconfigured to different shapes, e.g., Butterworth or Chebyshev with variable bandwidth (BW), based on the user requirements. In addition, an analytical synthesis procedure is introduced to realize high-order bandpass filters (BPFs) based on N-path architecture with a prescribed set of specifications. A proof-of-concept BPF is fabricated and measured in a 65-nm CMOS process. The filter can be reconfigured to realize different filter shapes by changing coupling capacitors. The BW of the proposed filter is also tunable. The passband of the filter is tunable from 0.2 to 1.2 GHz with a gain of 14.5–18 dB, a noise figure of 3.7–5.5 dB, and a total power consumption of 37.5–52.7 mW. The channel BW can be varied from 20 to 40 MHz and the filter out-of-band third-order intercept point ( $\Delta f=50$ MHz) is 25 dBm. [ABSTRACT FROM AUTHOR]

Fractional-order low-pass and high-pass Butterworth and Chebyshev filters with cut-off frequencies determined independently of their order are approximated in this work. The already available schemes in the literature have a cut-off frequency pre-determined by the pole frequency value, and hence the filter's order. The derivation of rational integer-order approximation functions, which approximate the frequency behavior of the filters, is performed through the utilization of a magnitude curve-fitting based method. The form of the transfer function is common for all filter functions, providing design versatility. Implementation is performed using just one active element, leading to a structure with minimized active component count. The evaluation of the accuracy of the employed approximation method is performed through numerical and experimental results, while the evaluation of the behavior of the active circuit topology is done using circuit simulations. [ABSTRACT FROM AUTHOR]

A circuit model for dual-mode resonators is proposed to develop a design procedure that facilitates the design of parallel-coupled dual-mode resonator filters. Based on the design procedure, a parallel-coupled dual-mode resonator filter can be designed in a way similar to the design of parallel-coupled line filters. Compared to the parallel-coupled line filter that uses half-wavelength line resonators, the use of dual-mode resonators not only achieves smaller size and better performance, but does not complicate the design and fabrication processes, as demonstrated in this paper. Accordingly, the parallel-coupled dual-mode resonator filter can be a good candidate for many practical applications that accept the Chebyshev or Butterworth response. [ABSTRACT FROM PUBLISHER]

Processes in digital filters are analyzed with consideration for the effects of quantization at an arbitrary number of digits in the representation of numbers and overflow under periodic external influences. An analysis technique based on representation of stationary oscillations as an invariant set of nonlinear discrete point mappings is used. The spectral composition of the system response and nonlinear distortions of signals with an arbitrary period are calculated with the use of classical and modernized discrete Fourier transforms. The results of calculations of processes in digital bandpass Butterworth and Chebyshev filters are presented. The dependences of the nonlinear distortion coefficient on the encoding type, the number of digits in the representation of numbers, and the order of the digital filter are demonstrated. The influence of the number of digits on frequency responses of filters is determined. [ABSTRACT FROM AUTHOR]

A simple method for approximation of all-pole recursive digital filters, directly in digital domain, is described. Transfer function of these filters, referred to as Ultraspherical filters, is controlled by order of the Ultraspherical polynomial, V. Parameter V, restricted to be a non-negative real number (V ≥ 0), controls ripple peaks in the passband of the magnitude response and enables a trade-off between the passband loss and the group delay response of the resulting filter. Chebyshev filters of the first and of the second kind, and also Legendre and Butterworth filters are shown to be special cases of these all-pole recursive digital filters. Closed form equations for the computation of the filter coefficients are provided. The design technique is illustrated with examples. [ABSTRACT FROM AUTHOR]

This paper introduces a new type of filter approximation method that utilizes shifted-modified Chebyshev filters. Construction of the new filters involves the use of shifted-modified Chebyshev polynomials that are formed using the roots of conventional Chebyshev polynomials. The study also includes 2 tables containing the shifted-modified Chebyshev polynomials and the normalized element values for the low-pass prototype filters up to degree 6. The transducer power gain, group delay, and impulse and step responses of the proposed filters are compared with those of the Butterworth and Chebyshev filters, and a sixth-order filter design example is presented to illustrate the implementation of the new method. [ABSTRACT FROM AUTHOR]

In this paper a new compact microstrip Bessel low pass filter (LPF) is experimentally validated using complementary split ring resonator (CSRR) which has sharper cut-off and improved spurious band suppression characteristics. The Richard's transformation and Kuroda's identities are used for realizing distributed Bessel LPF from the lumped element Bessel LPF. Traditionally Butterworth and Chebyshev LPFs are used in communication systems. Those LPFs exhibits high reflection in the pass-band and it is also very difficult to achieve sharper cut-off. Because of its poor cut-off and non linear phase characteristics, it will create cross talk between microwave systems. In order to overcome the above issues our proposed LPF which has linear phase and sharper cut-off behavior is an ideal subsystem in future microwave systems. Furthermore, to prove practical viability of the proposed design, a compact microstrip Bessel LPF was designed, simulated, fabricated and measured. It was observed from the experimentally compared results the proposed Bessel LPF with CSRR has better sharper cut-off characteristic than that without CSRR structure. [ABSTRACT FROM AUTHOR]

In this paper, the effect of different types of filters on the performance of a total least square–based receiver for a visible light communication system is studied. In the literature, the most common type of filter that is used is a matched filter. This is considered to be an optimal filter and it is commonly available. In the computationally limited environment, where there are not enough resources to match the needs of an optimal filter such as matched filter, this paper investigates the use of other potential filters such as Butterworth, elliptical, and Chebyshev filters. This paper also investigates the effect of choosing a suitable transmission band to countermeasure the effects of noise from artificial light sources and sun. The proposed system is analyzed on the parameter of bit error rate. In this paper, the effect of different types of filters on the performance of a TLS‐based receiver for a VLC is studied. A low‐cost system based on a Butterworth filter is proposed which performs better than a matched filter. The system was also analyzed by choosing a suitable transmission band to countermeasure the effects of noise. [ABSTRACT FROM AUTHOR]

A discrete-time charge-domain filter is proposed, which can realise complex conjugate poles in the transfer function of the filter. By employing a second transconductance in the feedback path of a second-order infinite impulse response charge-domain filter, it is proved that the filter topology is capable of implementing complex poles. This method makes charge-sampling filters more efficient in designing frequency-domain filters where they can be used to synthesise any type of filter structures such as Butterworth, Chebyshev and so on. [ABSTRACT FROM AUTHOR]