7,535 research outputs found
A 0.8 V T Network-Based 2.6 GHz Downconverter RFIC
A 2.6 GHz downconverter RFIC is designed and implemented using a 0.18 μm CMOS standard process. An important goal of the design is to achieve the high linearity that is required in WiMAX systems with a low supply voltage. A passive T phase-shift network is used as an RF input stage in a Gilbert cell to reduce supply voltage. A single supply voltage of 0.8 V is used with a power consumption of 5.87 mW. The T network-based downconverter achieves a conversion gain (CG) of 5 dB, a single-sideband noise figure (NF) of 16.16 dB, an RF-to-IF isolation of greater than 20 dB, and an input-referred third-order intercept point (IIP3) of 1 dBm when the LO power of -13 dBm is applied
On clocks and clouds
Cumulus clouds exhibit a life cycle that consists of (a) the growth phase
(increasing size, most notably in the vertical direction); (b) the mature
phase (growth ceases; any precipitation that develops is strongest during
this period); and (c) the dissipation phase (cloud dissipates because of
precipitation and/or entrainment; no more dynamical support). Although radar
can track clouds over time and give some sense of the age of a cloud, most
aircraft in situ measurements lack temporal context. We use large eddy
simulations of trade wind cumulus cloud fields from cases during the Barbados
Oceanographic and Meteorological Experiment (BOMEX) and Rain In Cumulus over
the Ocean (RICO) campaigns to demonstrate a potential cumulus cloud
"clock." We find that the volume-averaged total water mixing ratio rt
is a useful cloud clock for the 12 clouds studied. A cloud's initial rt
is set by the subcloud mixed-layer mean rt and decreases monotonically
from the initial value due primarily to entrainment. The clock is insensitive
to aerosol loading, environmental sounding and extrinsic cloud properties
such as lifetime and volume. In some cases (more commonly for larger clouds),
multiple pulses of buoyancy occur, which complicate the cumulus clock by
replenishing rt. The clock is most effectively used to classify clouds
by life phase
Scaling and memory in the return intervals of energy dissipation rate in three-dimensional fully developed turbulence
We study the statistical properties of return intervals between
successive energy dissipation rates above a certain threshold in
three-dimensional fully developed turbulence. We find that the distribution
function scales with the mean return interval as
except for , where the scaling function
has two power-law regimes. The return intervals are short-term and long-term
correlated and possess multifractal nature. The Hurst index of the return
intervals decays exponentially against , predicting that rare extreme
events with are also long-term correlated with the Hurst index
.Comment: 5 pages, 5 figure
Doubling of the bands in overdoped Bi2Sr2CaCu2O8-probable evidence for c-axis bilayer coupling
We present high resolution ARPES data of the bilayer superconductor
Bi2Sr2CaCu2O8 (Bi2212) showing a clear doubling of the near EF bands. This
splitting approaches zero along the (0,0)-(pi,pi) nodal line and is not
observed in single layer Bi2Sr2CuO6 (Bi2201), suggesting that the splitting is
due to the long sought after bilayer splitting effect. The splitting has a
magnitude of approximately 75 meV near the middle of the zone, extrapolating to
about 100 meV near the (pi,0) poin
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