81,392 research outputs found
Ultra Wide Band Signal Generator
Disclosed is an ultra wide band signal generator. The ultra wide band signal generator generates a signal of a required frequency using a harmonic signal having a frequency range of a ultra wide band (UWB). The ultra wide band signal generator includes an active inductor for generating harmonic signals having power strengths substantially equal to each other within a non-linear operation range, the tunable active inductor capable of tuning a value thereof, an oscillator for amplifying and outputting the harmonic signals generated from the active inductor by frequency-transiting the harmonic signals into high frequency bands, and a filter for selectively outputting one of the harmonic signals output from the oscillator.Samsung Electronics Co., LtdGeorgia Tech Research Corporatio
Periodicity in wide-band time series
Summary: To test the hypotheses that (i) electroencephalograms (EEGs) are largely made up of oscillations at many frequencies and (ii) that the peaks in the power spectra represent oscillations, we applied a new method, called the Period Specific Average (PSA) to a wide sample of EEGs. Both hypotheses can be rejected
Suzaku wide-band observations of SN 1006
We report on the wide band spectra of SN 1006 as observed by Suzaku. Thermal
and nonthermal emission are successfully resolved thanks to the excellent
spectral response of Suzaku's X-ray CCD XIS. The nonthermal emission cannot be
reproduced by a simple power-law model but needs a roll-off at 5.7 Hz = 0.23 keV. The roll-off frequency is significantly higher in the
northeastern rim than in the southwestern rim. We also have placed the most
stringent upper limit of the flux above 10 keV using the Hard X-ray Detector.Comment: 16 pages, 8 figures, PASJ, in pres
Wide-band doubler and sine wave quadrature generator
Phase-locked loop with photoresistive control, which provides both sine and cosine outputs for subcarrier demodulation, serves as a telemetry demodulator signal conditioner with a second harmonic signal for synchronization with the locally generated code
Sensitivity of wide band detectors to quintessential gravitons
There are no reasons why the energy spectra of the relic gravitons, amplified
by the pumping action of the background geometry, should not increase at high
frequencies. A typical example of this behavior are quintessential inflationary
models where the slopes of the energy spectra can be either blue or mildly
violet. In comparing the predictions of scenarios leading to blue and violet
graviton spectra we face the problem of correctly deriving the sensitivities of
the interferometric detectors. Indeed, the expression of the signal-to-noise
ratio not only depends upon the noise power spectra of the detectors but also
upon the spectral form of the signal and, therefore, one can reasonably expect
that models with different spectral behaviors will produce different
signal-to-noise ratios. By assuming monotonic (blue) spectra of relic gravitons
we will give general expressions for the signal-to-noise ratio in this class of
models. As an example we studied the case of quintessential gravitons. The
minimum achievable sensitivity to of different pairs of
detectors is computed, and compared with the theoretical expectations.Comment: 10 pages in Revtex style, 3 figure
Electronic Materials with Wide Band Gap: Recent Developments
The development of semiconductor electronics is shortly reviewed, beginning
with the development of germanium devices (band gap eV) after world
war II. Quickly a tendency to alternative materials with wider band gap became
apparent, starting with silicon ( eV). This improved the signal/noise
ratio for classical electronic applications. Both semiconductors have
tetrahedral coordination, and by isoelectronic alternative replacement of Ge or
Si with carbon or several anions and cations other semiconductors with wider
are obtained, that are transparent for visible light and belong to the
group of wide band gap semiconductors. Nowadays some nitrides, especially GaN
and AlN, are the most important materials for optical emission in the
ultraviolet and blue spectral region. Oxide crystals, such as ZnO and
-GaO, offer similarly good electronic properties but suffer
still from significant difficulties in obtaining stable and technically
sufficient -type conductivity.Comment: 25 pages, 8 figures, 4 table
Generating All Two-MOS-Transistor Amplifiers Leads to New Wide-Band LNAs
This paper presents a methodology that systematically generates all 2-MOS-transistor wide-band amplifiers, assuming that MOSFET is exploited as a voltage-controlled current source. This leads to new circuits. Their gain and noise factor have been compared to well-known wide-band amplifiers. One of the new circuits appears to have a relatively low noise factor, which is also gain independent. Based on this new circuit, a 50-900 MHz variable-gain wide-band LNA has been designed in 0.35-µm CMOS. Measurements show a noise figure between 4.3 and 4.9 dB for gains from 6 to 11 dB. These values are more than 2 dB lower than the noise figure of the wide-band common-gate LNA for the same input matching, power consumption, and voltage gain. IIP2 and IIP3 are better than 23.5 and 14.5 dBm, respectively, while the LNA drains only 1.5 mA at 3.3 V
High-resolution wide-band Fast Fourier Transform spectrometers
We describe the performance of our latest generations of sensitive wide-band
high-resolution digital Fast Fourier Transform Spectrometer (FFTS). Their
design, optimized for a wide range of radio astronomical applications, is
presented. Developed for operation with the GREAT far infrared heterodyne
spectrometer on-board SOFIA, the eXtended bandwidth FFTS (XFFTS) offers a high
instantaneous bandwidth of 2.5 GHz with 88.5 kHz spectral resolution and has
been in routine operation during SOFIA's Basic Science since July 2011. We
discuss the advanced field programmable gate array (FPGA) signal processing
pipeline, with an optimized multi-tap polyphase filter bank algorithm that
provides a nearly loss-less time-to-frequency data conversion with
significantly reduced frequency scallop and fast sidelobe fall-off. Our digital
spectrometers have been proven to be extremely reliable and robust, even under
the harsh environmental conditions of an airborne observatory, with
Allan-variance stability times of several 1000 seconds. An enhancement of the
present 2.5 GHz XFFTS will duplicate the number of spectral channels (64k),
offering spectroscopy with even better resolution during Cycle 1 observations.Comment: Accepted for publication in A&A (SOFIA/GREAT special issue
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