Prefilter bandwidth effects in data symbol phase synchronizers of open loop

This work studies the effects of the prefilter bandwidth on the open loop symbol synchronizers. We consider three different prefilter bandwidth, namely, B1=¥ ( infinite), B2=2.tx and B3=1.tx, where tx is the transmission rate. We consider also four open loop symbol synchronizers, namely, the tank (tank), the SAW (SAW), the monostable (mon), and the astable (ast). The objective is to study the prefilter bandwidth with the four open loop symbol synchronizers and to evaluate their output jitter UIRMS (Unit Interval Root Mean Square) versus input SNR (Signal to Noise Ratio)

Prefilter bandwidth effects in sequential symbol synchronizers based on clock sampling by positive transitions

This work studies the effects of the prefilter bandwidth in the sequential symbol synchronizers based on clock sampling by positive transitions. The prefilter bandwidth B is switched between three values, namely B1=∞, B2=2. tx and B3=1. tx, where tx is the bit rate. The synchronizer has two variants, one discrete and other continuous. Each variant has two versions, one manual and other automatic. The objective is to study the prefilter bandwidth with the four synchronizers and to evaluate their output jitter UIRMS (Unit Interval Root Mean Square) versus input SNR (Signal to Noise Ratio)

Effects of the previous pulse shift and filter on the symbol synchronizer PLL

We will study the effects of the shift of the previous pulse temporal position (between P1 and P2) on the symbol synchronizers jitter behavior. Each pulse temporal position (P1 and P2), with the same previous filter, forms a group with four different carrier PLL (Phase Lock Loop) namely the analog, hybrid, combinational and sequential. The main objective is to study the synchronizers output jitter UIRMS (Unit Interval Root Mean Squared) as function of the input SNR (Signal to Noise Ratio)

Sequential symbol synchronizers based on pulse comparison operating by positive transitions at quarter rate

This work presents the sequential symbol synchronizer based on pulse comparison by positive transitions at quarter rate (txp/4). Their performance is compared with a reference synchronizer by both transitions at the rate (tx). For the reference and proposed synchronizer we consider two versions which are the manual (m) and the automatic (a). The objective is to study the four synchronizers and evaluate their output jitter UIRMS (Unit Interval Root Mean Square) versus input SNR (Signal Noise Ratio)

Sequential symbol synchronizers based on clock sampling by positive transitions

This work presents a sequential symbol synchronizer, that was discovered by us, and its functioning principle is based on the clock sampling by the input positive data transitions. This synchronizer has two topologies, namely the discrete and the continuous. Also, each topology has two versions which are the manual and the automatic. These synchronizers are very interesting, because the previous adjust of the manual version isn’t critical. The objective is to study the four synchronizers and to evaluate their output jitter UIRMS (Unit Interval Root Mean Square) versus input SNR (Signal to Noise Ratio)

Sequential symbol synchronizers based on pulse comparation at Half Rate

This work presents a synchronizer based on pulse comparation, between variable and fixed pulses. We consider four synchronizers, divided in two variants, one variant operate at the rate and the other at half rate. Each synchronizer variant has two versions which are the manual and the automatic. The objective is to study the synchronizers and evaluate the output jitter UIRMS (Unit Interval Root Mean Square) versus the input SNR (Signal Noise Ratio)

Deterministic and random phase synchronizers

This work study two groups of synchronizers, namely the Deterministic Phase Synchronizer and the Random Phase Synchronizer. The difference between them is only inside of the phase comparator. In the first group, the VCO (Voltage Controlled Oscillator) synchronizes with the input deterministic phase of an expected periodic transition. In the second group the VCO synchronizes with the input random phase of an unexpected no periodic transition. Each group is studied under four topologies (analog, hybrid, combinational and sequential). The objective is to evaluate the two synchronizers groups with the four topologies and to observe their jitter behaviors with the noise

Performance Evaluation of Laboratory Wi-Fi ieee 802.11g wpa Point-to-Point Links Using TCP, UDP and FTP

AbstractWireless communications, e.g. Wi-Fi, have been increasingly important in the context of networked and virtual organizations and enterprise information systems. Performance is an issue of crucial importance, resulting in more reliable and efficient communications, therefore improving enterprise information system yield. Security is equally important. Laboratory measurements are made about several performance aspects of Wi-Fi IEEE 802.11g WPA point-to-point links. A contribution is given to performance evaluation of this technology under WPA encryption, using available equipments (DAP-1522 access points from D-Link and WPC600N adapters from Linksys). New detailed results are presented and discussed, namely at OSI levels 4 and 7, from TCP, UDP and FTP experiments, permitting measurements of TCP throughput, jitter, percentage datagram loss and FTP transfer rate. Comparisons are made to corresponding results obtained for open links. Conclusions are drawn about the comparative performance of the links

Tissue-specific regulation of IRS-1 in unilaterally nephrectomized rats

FAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOCNPQ – CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOInsulin stimulates the tyrosine kinase activity of its receptor, resulting in the phosphorylation of its cytosolic substrate, insulin receptor substrate 1 (IRS-1). IRS-1 is also a substrate for different peptides and growth factors, and a transgenic mouse knockout for this protein does not have normal growth. However, the role of IRS-1 in kidney hypertrophy and/or hyperplasia was not investigated. In the present study we investigated IRS-1 protein and tyrosine phosphorylation levels in the remnant kidney after unilateral nephrectomy (UNX) in 6-week-old male Wistar rats. After insulin stimulation the levels of insulin receptor and IRS-1 tyrosine phosphorylation were reduced to 79 ± 5% (P<0.005) and 58 ± 6% (P<0.0001), respectively, of the control (C) levels, in the remnant kidney. It is possible that a circulating factor and/or a local (paracrine) factor playing a role in kidney growth can influence the early steps of insulin action in parallel. To investigate the hypothesis of a circulating factor, we studied the early steps of insulin action in liver and muscle of unilateral nephrectomized rats. There was no change in pp185 tyrosine phosphorylation levels in liver (C 100 ± 12% vs UNX 89 ± 9%, NS) and muscle (C 100 ± 22% vs UNX 91 ± 17%, NS), and also there was no change in IRS-1 phosphorylation levels in both tissues. These data demonstrate that after unilateral nephrectomy there is a decrease in insulin-induced insulin receptor and IRS-1 tyrosine phosphorylation levels in kidney but not in liver and muscle. It will be of interest to investigate which factors, probably paracrine ones, regulate these early steps of insulin action in the contralateral kidney of unilaterally nephrectomized rats.Insulin stimulates the tyrosine kinase activity of its receptor, resulting in the phosphorylation of its cytosolic substrate, insulin receptor substrate 1 (IRS-1). IRS-1 is also a substrate for different peptides and growth factors, and a transgenic mouse knockout for this protein does not have normal growth. However, the role of IRS-1 in kidney hypertrophy and/or hyperplasia was not investigated. In the present study we investigated IRS-1 protein and tyrosine phosphorylation levels in the remnant kidney after unilateral nephrectomy (UNX) in 6-week-old male Wistar rats. After insulin stimulation the levels of insulin receptor and IRS-1 tyrosine phosphorylation were reduced to 79 ± 5% (P<0.005) and 58 ± 6% (P<0.0001), respectively, of the control (C) levels, in the remnant kidney. It is possible that a circulating factor and/or a local (paracrine) factor playing a role in kidney growth can influence the early steps of insulin action in parallel. To investigate the hypothesis of a circulating factor, we studied the early steps of insulin action in liver and muscle of unilateral nephrectomized rats. There was no change in pp185 tyrosine phosphorylation levels in liver (C 100 ± 12% vs UNX 89 ± 9%, NS) and muscle (C 100 ± 22% vs UNX 91 ± 17%, NS), and also there was no change in IRS-1 phosphorylation levels in both tissues. These data demonstrate that after unilateral nephrectomy there is a decrease in insulin-induced insulin receptor and IRS-1 tyrosine phosphorylation levels in kidney but not in liver and muscle. It will be of interest to investigate which factors, probably paracrine ones, regulate these early steps of insulin action in the contralateral kidney of unilaterally nephrectomized rats301011631167FAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOCNPQ – CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOFAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOCNPQ – CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOsem informaçãosem informaçã

Kaluza-Klein Type Robertson Walker Cosmological Model With Dynamical Cosmological Term Λ\Lambda

In this paper we have analyzed the Kaluza-Klein type Robertson Walker (RW) cosmological models by considering three different forms of variable $\Lambda$: $\Lambda\sim(\frac{\dot{a}}{a})^2$,$\Lambda\sim(\frac{\ddot{a}} {a})$ and $\Lambda \sim \rho$. It is found that, the connecting free parameters of the models with cosmic matter and vacuum energy density parameters are equivalent, in the context of higher dimensional space time. The expression for the look back time, luminosity distance and angular diameter distance are also derived. This work has thus generalized to higher dimensions the well-known results in four dimensional space time. It is found that there may be significant difference in principle at least, from the analogous situation in four dimensional space time.Comment: 16 pages, no figur