Notch Filters

This study describes a memcapacitor emulator without a multiplier that make use of second-generation current conveyor (CCII), operational transconductance amplifier (OTA) and the fewest possible passive components. The proposed memcapacitor is proved mathematically and verified using several simulation approaches, such as process corner, non-volatile and hysteresis analysis. Also, provided the layout of CCII and OTA as well. The standard CMOS 90 nm technology is used in the Cadence Virtuoso tool to simulate the proposed memcapacitor emulator. This article also includes the use of memcapacitor emulator in the applications of R-C frequency selective network as well as adaptable neuromorphic structure. To investigate the experimental outcomes, an experimental setup was constructed with commercially available integrated circuits (ICs) CCII's AD844AN and OTA's CA3080EZ.

The purpose of this paper is to examine the monopole micro-strip antenna types and ways to increase its bandwidth. These antennas have broadband properties. In this paper, a new design for monopole antenna flat-band broadband with removal properties was suggested. Using parametric analysis in this antenna, the ability of band removal, especially in the field of frequency band for WLAN / WiMAX, was created. The results of software simulation with HFSS were compared with the measurements results performed in communication research center. Antenna parameters such as VSWR and radiation pattern of the antenna together with software HFSS and antenna measurements in the laboratory with Network analyzer is given at the end of which all the results are in good agreement with experimental results.

A frequency reconfigurable printed slot antenna is designed and tested. The antenna consists of three slots fed through a microstrip transmission line. PIN diodes are appropriately positioned along their feeding points and by switching them to “OFF” or “ON” state, three frequency bands can be achieved. The left and middle slots cover 3.6-3.75 GHz and 3.33.4 GHz respectively, two bands typically used for WiMAX applications, while the right slot operates over 5.1-5.8 GHz that is suitable for wireless local area networks (WLANs). In order to match the input impedance of the antenna, a stub also is placed across the left slot and is active when its own diodes go to “ON” state. The overall size of this design is 25×25 mm that is smaller than the earlier works. The advantage is achieved by interconnecting two right slots.

Owing to the demand for frequency agility, a switchable ultra-wideband (UWB) hexagonal antenna was developed in this study. The proposed antenna features two notch filters introduced by two U-shaped slots on the patch to reduce interference from other wireless networks by rejecting the unique frequency bands. In addition, the proposed antenna comprises a hexagonal radiator attached to a feeding 50 Ω standard microstrip line. To fabricate the antenna prototype, a substrate (Rogers RT/Duroid 5880) with loss tangent and relative permittivity values of 0.0009, and 2.2, respectively, was used. Frequency and pattern reconfigurability were achieved by changing the electrical equivalent circuit of two positive-intrinsic-negative (PIN) diodes sandwiched within two U-shaped slots. The evaluation confirmed that the antenna operated within the D1&D2-ON configuration across the entire UWB range while, effectively filtering the wireless body area network (WBAN) (6.10-6.56 GHz) and radar application (9.16-10.79 GHz) bands when both diodes were OFF. The radiation efficiency and gain reached values of 92.9 % and 7.5 dB, respectively. The proposed design offers a robust performance with enhanced interference rejection. This makes it suitable for modern cognitive radio systems.

Advancements in ultra-wideband reconfigurable band-pass filters (BPF) with notch band function are required for modern communication systems operating across a broad frequency spectrum. This paper introduces an innovative design of a reconfigurable UWB BPF with notch functionality covering two separate operating states: 1st operating frequency band of 3.7 GHz-13 GHz with good insertion and return losses, at approximately 0.9 dB/58 dB respectively, and the 2nd operating frequency band from 2.7 GHz to 15 GHz incorporating 5.1 GHz-5.3 GHz notch band with insertion and return losses of 1.3 dB/57 dB respectively, using PIN/Varactor switches. Subsequently, a notch filter is strategically integrated into the design to suppress unwanted frequencies, enhancing the filter's selectivity and interference rejection capabilities. An experimental prototype for the reconfigurable filter with PIN diodes was fabricated to validate the effectiveness of the proposed design, demonstrating its suitability for UWB communication applications. Notably, the filter exhibits UWB characteristics, with a broad passband covering a wide frequency range with notch filtering to attenuate interfering signals. The compact size of the filter design 23.4 mm × 8.7 mm ensures practical integration into communication systems.

The electrocardiogram has considerable diagnostic significance, and application of ECG monitoring are diverse and in wide use. For diagnostic-quality ECG recordings, signal acquisition must be noise free. The signal acquisition is susceptible to the interference from other biological and environmental sources. This article presents the application of the digital IIR filter on the raw ECG signal. The filters utilized are Butterworth and elliptic notch and high pass filter. Complete design of the filters is depicted in the paper. At the end both the filter types are compared. It is found that the elliptic filter find suitable as compared to the Butterwoth with some limitations.

A tree shaped fractal antenna with U shaped slot and W-shaped slot has been designed and analyzed in this article by using ANSYS elec-tromagnetic desktop 17. The proposed antenna is analyzed taking FR4 substrate is taken as the substrate material. The proposed antenna exhibits multiband characteristics (2.75-3.17GHz, 4.1-4.8GHz, 5.1-5.3GHz and 5.4-6.3GHz, 7.21-12.8GHz) in the Ultra-wide band region. The path that is radiating by superposition of the rectangular patches and multiple-band operating frequency is obtained by increasing the U-shapes slots and w-shaped slot on the patch. The improvement in the impedance characteristics between the adjacent frequencies is achieved by using defected ground structure (DGS) on the ground plane as to cover the region of UWB application (3.1-10.6GHz). The proposed antenna works in the applications like Wi-Max, Weather forecasting RADAR systems and WLAN. 

In this paper, a miniaturized triple-band gap multi-via electromagnetic band gap (TBMV-EBG) structure is proposed. Lumped LC modelling method is used for the analysis of the proposed TBMV-EBG structure. Triple band gaps in both x and y-directions are obtained since TBMV-EBG unit cell consists of three resonance parallel LC circuits. Ansys (HFSS) simulation is used in eigen mode to simulate a unit cell of the proposed EBG. There is a strong agreement between simulated and experimental results. Comparing the proposed TBMV-EBG with triple band slotted EBG, triple band CSRR-EBG, fractal EBG, and dual band split EBG, size reductions of 6.52%, 7.53%, 23.21%, and 25.86% are obtained respectively which is validated by simulated and experimental results. Demonstration of the proposed TBMV-EBG structure for ultra-wideband (UWB) application is also presented. Simulation and measurement results prove that by using a single TBMV-EBG cell at the feed line of a UWB monopole antenna triple band-notches can be obtained. Moreover, switching characteristics of the proposed antenna are also demonstrated using single P-I-N diode. Depending on the ON and OFF switching status of P-I-N diode, the UWB antenna provides switching from triple band-notches to dual band-notches, respectively. The proposed switchable monopole UWB antenna as a single unit can be useful in applications wherein switching between multi-bands is desirable without changing the geometry of the structure.

Background and Objectives: Printed monopole antenna has an omnidirectional radiation pattern but a narrow impedance bandwidth. To achieve multiband behavior, modification of the antenna shape is necessary. There is no systematic approach for the shape modification and commonly it is done by parametric studies, adjusting, tuning or optimization of an initial shape. Methods: The method for designing a multiband antenna is based on transmission line theory and lumped element model. It applies to all desired multiband operations without needing tuning or optimizing a complex configuration. Every length and dimension are computed from the mathematical formula or Smith chart as a graphical tool. The proposed matching method in the design of a multiband and reconfigurable CPW-fed monopole antenna employed. Both series and parallel impedance matching stubs are investigated and compared with each other. Results: To explain the challenges, the proposed method was applied to a desired antenna. It showed that using matching stubs in the CPW line can design a multiband and reconfigurable antenna. Also, the measurements have been done and compared with the simulations and show a good agreement. Conclusion: Compared to the microstrip line, the CPW feeding of the monopole antenna has the advantage that both parallel and series stubs can be implemented for the matching of the antenna. In this case, the required space for these stubs placed inside the antenna and no extra space needed. So, the printed size of the proposed antenna does not change. The impedance matching method for the integrated stubs with the antenna has been proposed. The high-pass and low-pass properties of each matching network were considered. The authors showed that this method can successfully design multiband, reconfigurable CPW-fed monopole antennas.

Direct detection transceivers offer advantages, including low cost and complexity, in short-and medium-haul links. We carried out studies seeking to identify the signal formats which offer the highest information spectral densities and maximum transmission distances for direct detection links. The performance of two spectrally efficient optical signal formats, single-sideband (SSB) Nyquist pulse-shaped subcarrier modulation (SCM) and SSB orthogonal frequency-division multiplexing (OFDM), are compared by means of simulations. The comparison is performed for a range of wavelength-division multiplexing (WDM) net information spectral densities up to 2.0 b/s/Hz by varying the signal bandwidth, modulation cardinality, and WDM channel spacing. The signal formats' tolerance to signal-signal beating interference, resulting from square-law detection, is investigated, and the Nyquist-SCM format is found to suffer lower penalties from this nonlinearity at high information spectral densities. In 7 × 28 Gb/s WDM transmission at 2.0 b/s/Hz (with electronic predistortion and EDFA-only amplification), Nyquist-SCM signals can be transmitted over distances of up to 720 km of standard SMF in comparison to a maximum of 320 km with the OFDM signal format.

The paper investigates and compares the performances of two state-­of-­the-­art MultiHarmonic Sine Fitting (MHSF) algorithms when used in the dynamic testing of an Analog-­to-­Digital Converter (ADC). The influence of the initial estimate of the test signal frequency on the uncertainty of the estimated ADC dynamic parameters is analyzed by using computer simulations. Moreover, the accuracies of the considered MHSF algorithms and the sine-­fit algorithms suggested in the existing standards for ADCs testing are compared by means of both computer simulations and experimental results.

The control of flexible systems is often difficult due to the exact frequencies of the elastic modes being hard to identify. These flexible modes may change over time, or vary between units of the same system. The variation in the modal dynamics may cause a degradation in performance or even instabilities unless compensated for by the control scheme. Controllers designed for these types of systems use notch filters for suppression, however variation in the parameters of the flexible modes cause the need for wide notch filters. An adaptive scheme is proposed which uses an online estimator based on plant parameterization. Since the estimator is able to identify the modal dynamics, an adaptive notch filter is able to track an incorrectly modeled or varying flexible mode. The adaptive notch filter can be designed narrower, adding less phase lag at lower frequencies, thereby allowing an increase in bandwidth and disturbance rejection capability. Simulation and experimental verification of the adaptive mode suppression scheme is given through the use of a laser beam pointing system. The adaptive scheme is compared to a nonadaptive scheme, and is able to decrease the standard deviation of the experimentally measured tracking error by 14% even when the flexible dynamics are unknown.

In this paper all-optical non-return to zero to pseudo-return to zero format conversion limitations, using optical notch filters, are evaluated numerically. Open source simulation toolbox Optilux was used for simulations. Gauss and short term integrator notch filter performance and full width half maximum bandwidth impact on format conversion at transmission speed up to 40 Gbit/s was compared. Then format conversion performance was evaluated in a cascade of single ring microring resonators. Results show that large depth of an optical notch filter can cause two pulses generation at the edges of input pulses and lead to clock signal degradation.

A novel tunable microwave photonic notch filter using a phase-modulated dual-wavelength fiber laser is presented. A stable dual-wavelength erbium-doped fiber laser with a linear cavity is formed by a polarization-maintaining uniform fiber Bragg grating (PM-FBG) and a polarization maintaining linearly chirped fiber Bragg grating (PM-LCFBG), both of which were fabricated on a high-birefringence (Hi-Bi) fiber. It is found that a stable room-temperature dual-wavelength operation can be achieved due to the presence of two reflection peaks arising from the orthogonal states of polarization (SOP) of the PM-FBG. Experimental results show stable dual-wavelength lasing operation with a wavelength separation of $0.36 nm and a large optical signal-to-noise ratio (OSNR) of over 40 dB under room temperature. The dual-wavelength fiber laser is combined with a phase modulator and a segment of single-mode fiber (SMF) as a dispersive device to form a tunable microwave photonic notch filter. By stretching the PM-FBG to tune the wavelength separation of the dual-wavelength fiber laser, a tunable microwave photonic notch filter with various free spectral ranges (FSRs) and a rejection ratio greater than 35 dB was developed.

In this paper, a new miniaturized ultra-wideband bandpass filter is simulated. The structure of the new ultra-wideband bandpass filter is constructed using stepped-impedance resonator. The input admittance of the proposed filter is calculated and compared with the conventional structure. The frequency response of the filter is simulated by an EM simulator tool. The parameters of the proposed filter are optimized where this filter provides a ultra-wideband bandpass filter with a notch-band in the passband. Moreover, two transmission zeros exist on the lower and upper sides of the pass-band.

Electrocardiogram (ECG) wave suffers from several noise and interferences. The
noise and interferences include powerline noise, baseline wander, electromyogram and
electroencephalogram as the significant ones. The use of filters considerably improves signal
quality during recording. The objective of this work is to design and implement FIR digital
filter for reducing 50Hz interference, with hanning window function. Matlab simulated
results are presented.

A novel power-line interference (PLI) detection and suppression algorithm is presented to preprocess the electrocardiogram (ECG) signals. A distinct feature of this proposed algorithm is its ability to detect the presence of PLI in the ECG signal before applying the PLI suppression algorithm. No PLI suppression operation will be performed if PLI is not detected. We propose a PLI detector that employs an optimal linear discriminant analysis (LDA) algorithm to make a decision for the PLI presence. An efficient recursive least-squares (RLS) adaptive notch filter is also developed to serve the purpose of PLI suppression. Experimental results demonstrate superior performance of this proposed algorithm.

This paper presents results of digital CMOS design for ultra-low power filter that uses logic cells operating at nearthreshold voltage supplies. The cells were designed in 65 nm CMOS technology for ultra-low power. The hardware implementation of a pole-radius-varying Infinite Impulse Response (IIR) notch filter is addressed. Previous works have shown that digital design of pole-radius-varying (or Q factorvarying) IIR notch filters can suppress the transient effect. The proposed filter is synthesized using our custom 65 nm nearthreshold voltage standard cells library. Comparisons from nearthreshold operation to nominal voltages show large gains in energy-savings for this filter that make the logic architecture suitable for sub-nano-Joule per sample applications.

This paper focuses on some important concerns related to broadband power line communication (PLC) that emerged from regulation discussions resulting from observations of an experimental field trial conducted on low and medium voltage power lines by ANATEL, Brazil's telecommunications regulatory agency, and CELG, an electric power utility serving the country's center western region. Discussions are presented on the need to promote the coexistence of telecommunications systems in the 1.7-80 MHz frequency band, which includes the high frequency (HF) and part of the very high frequency (VHF) bands. The field test results of PLC system operation indicate that the presence of emissions justify the need to implement mitigation techniques, such as notch filters, dynamic frequency selection, cognitive radio concepts or any other strategies or devices that enable the coexistence of PLC systems with different telecommunications systems operating in the same frequency range.

In this paper, a new procedure for the design of a cascade of IIR Adaptive Notch Filters (ANFs) is presented. The cascade is composed by second-order sections of modified Nehorai Constrained ANFs, with coefficients modeled by a single polynomial of arbitrary order. This approach allows for a design with less parameters to control notch positions than the number of cascaded sections. The resulting structure is particularly suitable for tracking components of quasi-harmonic signals. An example shows that the coefficient modeling can tackle the inherent inharmonicity of the notes emitted by a string instrument. Finally, a complete adaptation algorithm for the model parameters, derived from Nehorai's ANF recursive prediction error algorithm, is described.