Effect Of Channel Spacing Research Articles

Study on the effect of channel spacing on premixed syngas-air explosion inside parallel narrow channels

Study on the effect of channel spacing on premixed syngas-air explosion inside parallel narrow channels

Investigation the Effect of Channel Spacing for Long Distance Communication

In this paper, the impact of different channel spacing on proposed system setup is investigated for long distance communication. This wavelength division multiplexing (WDM), dense wavelength division multiplexing (DWDM) and ultradense wavelength division multiplexing (UDWDM) is evaluated by considering the signal quality factor, bit error rate, optical gain, and received power for different signal input power and for distance. It is observed that at -5 dBm of signal input power the system covers 130 km with acceptable BER (10-8) and Q-factor (14dB).

Effect of channel separation and interaural mismatch on fusion and lateralization in normal-hearing and cochlear-implant listeners.

Bilateral cochlear implantation has provided access to some of the benefits of binaural hearing enjoyed by normal-hearing (NH) listeners. However, a gap in performance still exists between the two populations. Single-channel stimulation studies have shown that interaural place-of-stimulation mismatch (IPM) due to differences in implantation depth leads to decreased binaural fusion and lateralization of interaural time and level differences (ITDs and ILDs, respectively). While single-channel studies are informative, multi-channel stimulation is needed for good speech understanding with cochlear implants (CIs). Some multi-channel studies have shown that channel interaction due to current spread can affect ITD sensitivity. In this work, we studied the effect of IPM and channel spacing, along with their potential interaction, on binaural fusion and ITD/ILD lateralization. Experiments were conducted in adult NH listeners and CI listeners with a history of acoustic hearing. Results showed that IPM reduced the range of lateralization for ITDs but not ILDs. CI listeners were more likely to report a fused percept in the presence of IPM with multi-channel stimulation than NH listeners. However, no effect of channel spacing was found. These results suggest that IPM should be accounted for in clinical mapping practices in order to maximize bilateral CI benefits.

Effect of Channel Spacing on the Design of Mixed Line Rate Optical Wavelength Division Multiplexed Networks

Abstract The ever increasing heterogeneity and growing traffic volume has resulted in significant innovations and paradigm shifts within the telecom backbone networks. In order to cost-effectively respond to the diverse variety of traffic requirements having heterogeneous service demands, wavelength division multiplexed (WDM) optical networks have adopted the mixed line rate (MLR) strategy. In MLR networks, many wavelength channels with various line rates can co-exist within the same fiber which, however, raises many important design issues; one of them being the choice of the channel spacing. The quality of signal is affected by the channel spacing in terms of the bit-error rate (BER), which in turn affects the maximum optical reach of the lightpaths that depends on the line rates. In regard to the aforementioned, different methods can be adopted in order to set the width of the channel spacing, viz., (a) choice of a 50 GHz uniform fixed channel spacing specified by the ITU-T grid, (b) exploring various channel spacing values for different line rates so as to optimize the usage of the fiber spectrum, or (c) seek for an optimal value of the channel spacing which results in the minimum network cost. In the current work, we evaluate the MLR network cost for various channel spacings; hence, we find an optimal value of the channel spacing that leads to the minimum MLR network cost. The simulation results reveal that, for a MLR network, even with the assumption of uniform channel spacing, optimal values of the channel spacing for a minimum cost network can be identified.

Optical Mitigation of Interchannel Crosstalk for Multiple Spectrally Overlapped 20-GBd QPSK/16-QAM WDM Channels Using Nonlinear Wave Mixing

Optical mitigation of interchannel interference (ICI) for multiple spectrally overlapped data channels is experimentally demonstrated without multichannel detection and channel spacing estimation. The ICI mitigation takes place in three stages of periodically poled lithium niobate (PPLN) waveguides. In the first PPLN stage, the conjugate copies of channels are generated. In the second stage, the overlapped signals are coherently multiplexed with different complex taps. In the third stage, the concurrent nonlinear processes and the coherent multiplexing of the signals with their delayed copies compensate the ICI. The bit error rate and the constellation diagrams of wavelength division multiplexed (WDM) channels carrying quadrature phase-shift keying (QPSK) or 16 quadrature amplitude modulation (16-QAM) formats demonstrate the potential capability of the proposed method to reduce the ICI and its possible modulation format transparency. The effect of channel spacing on the performance of the method is also demonstrated. After optical ICI mitigation, a reduction of almost 4 dB is achieved for the value of optical signal-to-noise ratio at BER of 10–3 for 20-GBd QPSK signals with a channel spacing of 17.5 GHz. The overlapped WDM system of 20-GBd 16-QAM signals with channel spacing of 17.5 GHz is also ICI mitigated and error vector magnitudes are reduced by almost 28%.

Simulative Analysis of Inter-Satellite Optical Wireless Communication (IsOWC) Link with EDFA

Abstract In this paper, simulative analysis and performance comparison of different EDFA (Erbium-doped fiber amplifier) configurations in a 10 Gbps inter-satellite optical wireless communication (IsOWC) link have been reported for a 5,000 km long link and 1,550 nm operating wavelength. The results show that system in which both pre-amplifier and booster amplifier stages are implemented simultaneously outperforms systems with only pre-amplifier and booster amplifier stage. From the results, it can be seen that by deploying a transmission power level of 15 dBm, a link distance of 9,600 km can be achieved with a quality factor of 6.01 dB and BER (Bit error rate) of 1.07 × 10 − 9 $$1.07 \times {10^{- 9}}$$ . Also, in this paper, the performance of an 8×7 Gbps WDM-IsOWC link has been reported. The results show that by using both EDFA pre-amplifier and booster amplifier stages, a link distance of 8,000 km for each channel is achievable with desired performance levels (Q≥6 and BER≤ 10 − 9 $${10^{- 9}}$$ ). Also, the effect of channel spacing on the performance of WDM-IsOWC link is investigated. The results show that the received signal has acceptable performance levels when the channel spacing is 100 GHz but when the channel spacing is reduced to 80 GHz, the quality of the received signal degrades and link distance decreases.

Analysis of SDWDM Ring Network and Enhancement Using Different Hybrid Optical Amplifiers and Modulation Formats

AbstractIn this paper, performance enhancement of super-dense wavelength division multiplexing (SDWDM) optical add–drop multiplexer optical ring network for six nodes, 50 wavelengths having channel spacing of 0.2 nm for 300 km unidirectional nonlinear fiber is successfully demonstrated. The performance of the designed system is enhanced by comparing different modulation formats (non-return to zero (NRZ), return to zero (RZ), soliton, chirped return to zero (CRZ), carrier-suppressed RZ (CSRZ)) and hybrid amplifiers (Erbium-doped fiber amplifier (EDFA)–EDFA, semiconductor optical amplifier (SOA)–SOA, SOA, EDFA, EDFA–SOA) on the basis of eye diagram and bit error rate (BER). It has been observed that CRZ modulation format and EDFA-SOA shows the best results. It has been reported that EDFA-SOA/CRZ modulation format can achieve BER as better as e-13, which gives best performance. The effect of channel spacing on SDWDM system and performance degradation due to crosstalk is also evaluated.

Performance Optimization of 45-Channel Superdense Wavelength-Division-Multiplexed (SDWDM) Optical Add–Drop Multiplexer (OADM) Ring Network

AbstractIn this paper, performance analysis of high-speed superdense wavelength-division-multiplexing (SDWDM) optical add–drop multiplexer (OADM) optical ring network for 6 nodes, 45 wavelengths having channel spacing of 0.2 nm on 300 km unidirectional nonlinear single-mode fiber ring of 10 Gbit/s has been reported. The performance optimization of the system by comparing different modulation formats has been reported on the basis of eye diagram and bit error rate (BER). It has been reported that CSRZ modulation format can achieve BER as better as e-24, which gives best performance. This paper also presents a study of performance degradation caused by the crosstalk and the effect of channel spacing on SWDM system.

Suppress the FWM by Increasing Channel Spacing and Chromatic Dispersion of Fiber in WDM System

AbstractIn this paper, we investigate the effect of channel spacing and chromatic dispersion on four wave mixing in WDM system. Dominating effect of four wave mixing is minimizing at maximum value of dispersion and channel spacing. Power of FWM, Q-factor, bit error rate and output spectrum is used to measure the performance of system.

Heat transfer and pressure drop in corrugated channels

Abstract The convective heat transfer and pressure drop characteristics of flow in corrugated channels have been experimentally investigated. Experiments were performed on channels of uniform wall temperature and of fixed corrugation ratio over a range of Reynolds number, 3220 ≤ Re ≤ 9420. The effects of channel spacing and phase shift variations on heat transfer and pressure drop are discussed. Results of corrugated channels flow showed a significant heat transfer enhancement accompanied by increased pressure drop penalty. The average heat transfer coefficient and pressure drop enhanced by a factor of 2.6 up to 3.2 and 1.9 to 2.6 relative to those for parallel plate channel, respectively, depending upon the spacing and phase shift. The friction factor increased with increasing channel spacing and its phase shift. The effect of spacing variations on heat transfer and friction factor was more pronounced than that of phase shift variation, especially at high Reynolds number. Comparing results of the tested channels by considering the flow area goodness factor ( j / f ), it was better for corrugated channel with spacing ratio, ɛ ≤ 3.0 and of phase shift, O ≤ 90°. Comparisons of the present data with those available in literature are presented and discussed.

The effect of channel spacing during magma migration on trace element and isotopic ratios

An analytical, mathematical model is discussed for the transport of trace element and isotopic ratios during magma migration, when no major dissolution or precipitation of minerals occurs, but diffusive exchange of atoms between magma and solid is important. This model is then used to elucidate the effect of channel spacing on the transport of trace element and isotopic ratios during the migration of basaltic magma. It is found that, when total reequilibration occurs, as it will in migration through closely spaced channels on grain boundaries, isotopic ratios are transmitted to the surface unchanged but trace element ratios may vary wildly. When channels are far enough apart so that only partial reequilibration occurs, variations in both isotopic and trace element ratios are reduced or eliminated during magma migration. Finally, when channels are sufficiently distant so that negligible reequilibration occurs, both trace element and isotopic ratios are transmitted to the surface unchanged.

Effect of channel spacing in an optical two-channel DPSK transmission system with optical amplifiers

In a two-channel 560 Mbit/s DPSK system with optical broadband amplifiers the effect of channel spacing is investigated. The main crosstalk mechanism is independent of the amplifiers. It is caused by the spectral overlap of the two channels. No additional crosstalk due to four-wave mixing in the amplifier is found.

Heat Transfer in Electronic Systems With Emphasis on Asymmetric Heating

The trend in electronic circuit design is toward increasing power dissipation density. The performance and reliability of increasing number of electronic systems are now seriously threatened by thermal effects, so that it is necessary to reappraise the relevant thermal design procedures. This paper examines natural convection cooling and concerns the prediction of maximum temperatures of electronic cabinets containing arrays of vertically oriented circuit cards with unequal power dissipation levels. By means of a vertical channel model, the effects of channel spacing, channel height, and power dissipation level are assessed with emphasis on asymmetric powering of the channel walls. Methods are indicated for rapid evaluation of maximum temperatures and optimum channel spacing with asymmetric heating. The present results show that asymmetry reduces the thermal performance of the channel. Consequently, the power dissipation on the channel walls should be made nearly equal.