83,611 research outputs found
Duty-cycle division multiplexing (DCDM): a novel and economical optical multiplexing and electrical demultiplexing technique for high speed fiber optics networks
A new multiplexing and demultiplexing technique based on duty cycle division is proposed, thus the name duty cycle division multiplexing (DCDM). DCDM can be applied in both electrical and optical domains. The new technique allows for more efficient use of time slots as well as the spectrum, taking advantage of both the conventional TDM and FDM. In this paper, three channels operating at the same speed of 10 Gbps are multiplexed in the optical domain and demultiplexed in the electrical domain. The performance comparison is made against 30 Gbps TDM, and the experimental simulation results show that the minimum sensitivity achieved is -26 dBm and -25.5 dBm for the two systems respectively, thus a 0.5 dB improvement
Load cell for thermionic converter tests
Stable, low duty cycle transistorized emitter follower load cell controls and absorbs large currents at low voltages. The use of energy storage in capacitors reduces auxiliary power source requirements. Low duty cycle pulse mode of operation reduces the average power handling requirement of all components
Constraining the duty cycle of transient low-mass X-ray binaries through simulations
We performed simulations of a large number of so-called very faint X-ray
transient sources from surveys obtained using the X-ray telescope aboard the
Neil Gehrels \emph{Swift} Observatory on two Galactic globular clusters, and
the Galactic Center. We calculated the ratio between the duty cycle we input in
our simulations and the one we measure after the simulations. We found that
fluctuations in outburst duration and recurrence times affect our estimation of
the duty cycle more than non detected outbursts. This biases our measures to
overestimate the simulated duty cycle of sources. Moreover, we determined that
compact surveys are necessary to detect outbursts with short duration because
they could fall in gaps between observations, if such gaps are longer than
their duration. On the other hand, long surveys are necessary to detect sources
with low duty cycle because the smallest duty cycle a survey can observe is
given by the ratio between the shortest outburst duration and the total length
of the survey. If one has a limited amount of observing time, these two effects
are competing, and a compromise is required which is set by the goals of the
proposed survey. We have also performed simulations with several artificial
survey strategies in order to evaluate the optimal observing campaign aimed at
detecting transients as well as at having the most accurate estimates of the
duty cycle. As expected, the best campaign would be a regular and dense
monitoring that extends for a very long period. The closest real example of
such a dataset is the monitoring of the Galactic Centre.Comment: 13 pages, 6 figures. Accepted for publication in MNRA
A Simple BATSE Measure of GRB Duty Cycle
We introduce a definition of gamma-ray burst (GRB) duty cycle that describes
the GRB's efficiency as an emitter; it is the GRB's average flux relative to
the peak flux. This GRB duty cycle is easily described in terms of measured
BATSE parameters; it is essentially fluence divided by the quantity peak flux
times duration. Since fluence and duration are two of the three defining
characteristics of the GRB classes identified by statistical clustering
techniques (the other is spectral hardness), duty cycle is a potentially
valuable probe for studying properties of these classes.Comment: 4 pages, 1 figure, presented at the 5th Huntsville Gamma-Ray Burst
Symposiu
Wi-Fi Coexistence with Duty Cycled LTE-U
Coexistence of Wi-Fi and LTE-Unlicensed (LTE-U) technologies has drawn
significant concern in industry. In this paper, we investigate the Wi-Fi
performance in the presence of duty cycle based LTE-U transmission on the same
channel. More specifically, one LTE-U cell and one Wi-Fi basic service set
(BSS) coexist by allowing LTE-U devices transmit their signals only in
predetermined duty cycles. Wi-Fi stations, on the other hand, simply contend
the shared channel using the distributed coordination function (DCF) protocol
without cooperation with the LTE-U system or prior knowledge about the duty
cycle period or duty cycle of LTE-U transmission. We define the fairness of the
above scheme as the difference between Wi-Fi performance loss ratio
(considering a defined reference performance) and the LTE-U duty cycle (or
function of LTE-U duty cycle). Depending on the interference to noise ratio
(INR) being above or below -62dbm, we classify the LTE-U interference as strong
or weak and establish mathematical models accordingly. The average throughput
and average service time of Wi-Fi are both formulated as functions of Wi-Fi and
LTE-U system parameters using probability theory. Lastly, we use the Monte
Carlo analysis to demonstrate the fairness of Wi-Fi and LTE-U air time sharing
Constant-frequency, variable-duty-cycle multivibrator
Circuit provides a pulse source of constant frequency with a duty cycle that is adjustable by an external input signal. It could serve as a switching mode voltage regulator or as a switching source for control systems
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