Showing papers on "Bessel filter published in 2018"

A Study of the Effect of Integrating Low-Pass Filter in Measuring the Dynamic Performance of a High Speed 8-bit Analog-to-Digital Converter (ADC)

Abstract: This research focuses on integrating a low pass filter to the AD7575 DUT Board to measure its dynamic performance. The DUT Board integrated with the low-pass filter was attached to the ADI Family Board and was tested using the CTS5010 resources to measure the necessary dynamic performance parameters. The low pass filter was used to lessen the out-of-bound noise going into the ADC input that affects the measurement of dynamic performance of the ADC. Three active low pass filters were designed on the circuit board, namely Butterworth, Chebyshev and Bessel Filter. The integration of the filter showed significant change, with the Butterworth filter giving better measurement as compared to the other low-pass filters used.

Performance Evaluation of WDM-FSO Based Hybrid Optical Amplifier Using Bessel Filter

Abstract: Free space optics systems (FSO) has been proved to be for cost effective providing high security, easy installation, wider bandwidth and high data rate information exchange. FSO also solve the last mile problem to solution. Main limitation of FSO is the attenuation effect due to environment. Haze and rain are the most important factor to the free space optical (FSO) link. Signal power has been increased using optical amplifier in FSO by WDM and then analyzed at 2.5 Gbps to get the desired signal. The WDM based FSO system for worst weather condition using hybrid configuration of optical amplifier (EDFA, SOA) is proposed which provide a solution for more efficient system and low cost. Further the system is compared with the existing results. The proposed model enhance the performance in terms of BER and Q-factor at the receiver end of the system.

An Optical Duobinary Downlink Access Scheme Using Low Pass Filter and its Application

Abstract: In this letter, a novel optical duobinary (ODB) downlink access scheme using low pass filter was proposed. The ODB downlink signal was generated by one continuous-wave (CW) laser, one pseudo-random binary sequence (PRBS) generator, one NRZ generator, one precoder, one Mach-Zehnder modulator and one low pass Bessel filter. The downlink signal can be transmitted over 20km singlemode fiber (SMF) and successfully received. We analyzed the time-domain waveforms, optical spectrum and eye diagrams before and after downstream transmission. The simulation results show that, compared to the traditional downlink scheme, this scheme has the advantages of high bandwidth efficiency, resistance to dispersion and good reception performance.

Numerical computation of infinite Bessel transforms with high frequency

Abstract: In this paper numerical evaluation of infinite Bessel transforms with high frequency is considered. We first derive an asymptotic formula by using the integration by parts. Next we use an interpolation formula to evaluate the infinite Bessel transforms by choosing the suitable basis and nodes. The corresponding error results are proved, and numerical examples are shown to illustrate the efficiency and accuracy of the presented formulae.

Notice of Retraction: Frequency Analysis of Memristor Based Low Pass Bessel Filter

Abstract: Bessel filter is a type of linear form filter, which is widely used for applications where constant group delay response is required. Such implementation allows to avoid linear distortion. It is believed that recent realization of memristor element can significantly affect filter's performance by being able to adjust filter gain and cut-off frequency. Therefore, this paper presents a memristor based active low pass Bessel filter, where resistor elements were replaced by memristors. The circuit is analysed by on frequency response. Memristor resistances are to be adjusted by means of tuning circuits. Overall, memristive circuit resulted in slight deviation from the original circuit with the same power consumption and verified adjustability of several filter characteristics.

Design of a novel Equalizer-Driver with 3.7 V pp diff linear output swing and 16 dB of peaking gain at 55 GHz for 64 GBd PAM-4 optical communication transmitters

Abstract: This paper introduces a novel Equalizer-Driver that combines equalizing and driving functionalities in a single function aimed at increasing the bandwidth and energy efficiency of electro-optical (E/O) transmitters. Implemented in III-V Lab’s 0.7-µm InP DHBT technology, the Equalizer-Driver exhibits in full EM-circuit co-simulation 13 dB of differential gain (S d2d1 ) at 10 MHz and 16 dB of peaking gain at 55 GHz, for a total intrinsic -3 dB-bandwidth over 100 GHz. Transient simulations show it is able to provide an equalized and amplified 3.7-V pp diff linear output signal in PAM4 at 64 GBd, from an input signal filtered by a Bessel filter with a 17-GHz -3 dB-bandwidth. Consuming 1.2 W at its maximum 3.7-V pp diff linear output swing, it is well suited for bandwidth limited optical transmitters at 64 GBd and beyond.

APD detection device for full-waveform measurement lidar

Abstract: The invention discloses an APD detection device for a full-waveform measurement lidar, which comprises an APD photoelectric sensing module, a transimpedance amplifier module, a voltage amplifier module, a filter module, an adjustable high voltage module, a temperature sensing module, an interface module and a low voltage power supply module. A gain chain structure with the transimpedance amplifierand the multistage voltage amplifier cascaded is adopted, and low noise, high bandwidth and high gain current-voltage conversion and amplification on weak current outputted by the APD photoelectric sensor can be realized; the high-order Bessel filter is adopted to filter out-of-band noise, the system sensitivity is enhanced, and nonlinear distortion is not generated for the signal waveform; a bias voltage real time adjustment method is adopted, the response nonlinearity problem brought by temperature changes to the APD photoelectric sensor is overcome, and high-linearity photoelectric detection is realized. High sensitivity, high dynamics and high linearity detection requirements of light signal receiving by the full-waveform measurement lidar system can be effectively solved, and the device is also applicable to other lidar systems and weak light signal detection situations.

Settling-time oriented OTA design through the approximation of the ideal delay

Abstract: In this communication we propose a simple and well-defined approach for the design of fast settling amplifiers suitable for switched capacitors circuits. The design is based on a settling-time oriented compensation that makes the phase of the closed-loop amplifier to be linearly related to the frequency, thus emulating the behavior of an ideal delay, like in a Bessel filter. The design and the simulation of a three-stage amplifier in a 65-nm CMOS process validate the proposed settling-time oriented approach.

Optical Communication Using Linear Sums of Optical Receiver Modes: Proof of Concept

Abstract: We demonstrate the feasibility of an optical communication system that transmits linear sums of optical receiver modes (ORMs) as optical signals called ORM signals The ORMs are inherent modes of conventional direct-detection optical receivers for wavelength-division multiplexing systems Two lowest order ORMs are used to build ORM signals having distinct received voltage waveforms from each other The optical receiver used has a Fabry–Perot filter as its optical filter and a fourth-order Bessel filter as its electrical filter With these filters, corresponding ORMs are evaluated numerically and the ORM signals are generated using digital-to-analog converters The received voltage waveforms after the receiver electrical filter are in good agreement with our analysis

Simulated Sensitivity Improvement of Optical Receiver in Fiber Optic Network

Abstract: With the increasing demand and growth in optical telecommunication networks, the sensitivity of an optical receiver become an important part of telecommunication transmission networks. The unlimited bandwidth of an optical fiber create a path for large volume of signals to flow rapidly in a fraction of a seconds. This increase in the volume of transmitted signals causes severe traffic congestion, making the receiver insensitive, prolong the signal processing time and identified bits wrongly. In this research, Optisystem 7 professional software using Erbium Doped Fiber (EDF), Avalanche photodiode (APD), Non-Return-to-Zero modulation format, optimization tool and low pass Bessel filter, CW laser, pump laser, a gain flattering filter, attenuator, Bit Error Rate Analyzer (BER) etc, was used to improve the sensitivity of the receiver. The procedure of the design was to first improve on the gain using Erbium Doped Fiber Amplifier (EDFA), reduce loss and propagation time and increase the signal flow. Optisystem simulation was used to determine the optimum gain and the receiver sensitivity for several values of attenuation. This research investigated and analyzed the performance of the optical receiver at a wavelength of 1550nm, optic fiber of length 100km. Simulations were made and the Bit Error Rate analyzer values taken. Several values of Q-Factor and Bit Error Rate were tabulated and the corresponding graphs plotted. There was an improvement in the gain, quality factor, the quality of signal with a low noise value and the extended transmission or propagation time was reduced. The result of the design showed an improvement in the sensitivity of the receiver.

To compensate RoF non-linear transmission impairments: Simulation vs Analytical modeling

Abstract: In this paper, validation of simulation results through analytical modelling has been presented to compensate the impact of non-linear transmission impairments such as Self-Phase Modulation (SPM), Four-Wave Mixing (FWM) and Cross-Phase Modulation (XPM)in RoF (Radio over Fiber) system. An analytical model has been designed and validated with the simulation results. The proposed analytical model utilizes SSP (Symmetrical-Symmetrical-Post), Bessel filter and PC-DCF (Post Compensating-Dispersion Compensation Fiber) compensation techniques in the transmission channel to mitigate SPM, FWM and XPM effects in RoF system. The simulation results indicate a reasonable improvement in OSNR by 2dB and by 5dB by using SSP and PC-DCF compensation technique. In addition to these results, reduction in FWM sideband power has been analyzed by 4dBm by the incorporation of Bessel Filter in the transmission channel. Through analytical modelling, it is seen that the simulation results obtained are in close proximity for compensating non-linear transmission effects such as SPM, FWM and XPM.

Performance evaluation of high data rate dwdm system with tw-soa

Abstract: WDM technology act as important role in fiber optic communication. Dense wavelength division multiplexing (DWDM) is the major technology that can transmit multiple information streams simultaneously over the single fiber with reduced channel spacing. The optical fiber has established great application in long distance communications. In this paper, a 80 channel DWDM system is modeled with 0.1 nm channel spacing in the presence of travelling wave semi-conductor optical amplifier (TW-SOA). The performance of Bessel WDM mux/demux filter for various order of low pass Bessel filter has simulated and analyzed for 200 km distances at 160Gbps bitrate to improve the quality factor of this system model. The performance of the simulation system has been investigated in terms of quality (Q) factor and bit error rate (BER) by using Optisystem simulator 7.

Frequency Analysis of Memristor Based Low Pass Bessel Filter

Abstract: Bessel filter is a type of linear form filter, which is widely used for applications where constant group delay response is required. Such implementation allows to avoid linear distortion. It is believed that recent realization of memristor element can significantly affect filter's performance by being able to adjust filter gain and cut-off frequency. Therefore, this paper presents a memristor based active low pass Bessel filter, where resistor elements were replaced by memristors. The circuit is analysed by on frequency response. Memristor resistances are to be adjusted by means of tuning circuits. Overall, memristive circuit resulted in slight deviation from the original circuit with the same power consumption and verified adjustability of several filter characteristics.

Implementation of Memristor in Bessel filter with RLC components

Abstract: The Bessel filters are optimized to collect competent transient response due to a linear phase in the passband. In other words, during the filtering process, there will be comparatively impoverished frequency response with lower amplitude inequity. Memristor is asserted as a passive, two-terminal essential component of the circuit and the use of such element in schemes as an adjustable resistance allows the realization of memory-resistor based analog circuits, which achieve the wide range of specific parameters. The application of RLC circuit for Bessel filter prototype is theoretically expected to behave in a positive way, however, the further simulations with software and analysis of the results will reveal the nature of the effect.

Implementation of Memristor in Bessel filter with RLC components

Abstract: The Bessel filters are optimized to collect competent transient response due to a linear phase in the passband. In other words, during the filtering process, there will be comparatively impoverished frequency response with lower amplitude inequity. Memristor is asserted as a passive, two-terminal essential component of the circuit and the use of such element in schemes as an adjustable resistance allows the realization of the memory resistor based analog circuits, which achieve the wide range of specific parameters. The application of RLC circuit for Bessel filter prototype is theoretically expected to behave in a positive way, however, the further simulations with software and analysis of the results will reveal the nature of the effect