12 research outputs found
DESAIN FILTER UNTUK MENGURANGI DISTORSI HARMONIK DAN MEMPERBAIKI FAKTOR DAYA SISTEM KELISTRIKAN DI GEDUNG ADMINISTASI PUSAT POLINES
Peralatan listrik perkantoran pada gedung administrasi pusat Polines didominasi oleh komputer, AC,printer, TV, dan proyektor dimana beban tersebut adalah beban non linear. Tipe beban seperti ini dapatmenimbulkan total rugi-rugi yang disebut total harmonic distortion (THD). Nilai THD dibawah standardapat menyebabkan kerusakan pada peralatan listrik pada pemakaian jangka panjang. Penelitian inibertujuan merancang filter harmonik untuk menekan angka THD yang tinggi. Filter yang digunakanadalah filter low pass ordo dua yang merupakan jenis filter aktif. Arus listrik terukur untuk mensuplaigedung administrasi pusat untuk tiap fasa R, S, T masing-masing adalah 29,37 A, 30,06 A, dan 28,95 A dengan nilai THD masing-masing 13,73 %, 22,75 %, dan 9,48 %.. Nilai arus setelah melewati prosesfilter adalah 29,96 A, 30,16 A, 29,61 A dengan nilai THD masing-masing 1,55 % 3,95 %, dan 3,36 %.Rata-rata THD arus (THDi) tanpa filter adalah 15,32 %, sedangkan THD arus (THDi) menggunakan filteradalah 2,95 %. THD arus untuk tiap fasa setelah melewati proses filterisasi sudah memenuhi standarharmonik yang diijinkan, yaitu sudah dibawah 8%. Kata Kunci:
Integrated Electronics for Wireless Imaging Microsystems with CMUT Arrays
Integration of transducer arrays with interface electronics in the form of single-chip CMUT-on-CMOS has emerged into the field of medical ultrasound imaging
and is transforming this field. It has already been used in several commercial products such as handheld full-body imagers and it is being implemented by commercial and academic groups for Intravascular Ultrasound and Intracardiac Echocardiography. However, large attenuation of ultrasonic waves transmitted through
the skull has prevented ultrasound imaging of the brain. This research is a prime
step toward implantable wireless microsystems that use ultrasound to image the
brain by bypassing the skull. These microsystems offer autonomous scanning
(beam steering and focusing) of the brain and transferring data out of the brain for
further processing and image reconstruction.
The objective of the presented research is to develop building blocks of an integrated electronics architecture for CMUT based wireless ultrasound imaging systems while providing a fundamental study on interfacing CMUT arrays with their
associated integrated electronics in terms of electrical power transfer and acoustic
reflection which would potentially lead to more efficient and high-performance
systems.
A fully wireless architecture for ultrasound imaging is demonstrated for the
first time. An on-chip programmable transmit (TX) beamformer enables phased
array focusing and steering of ultrasound waves in the transmit mode while its
on-chip bandpass noise shaping digitizer followed by an ultra-wideband (UWB)
uplink transmitter minimizes the effect of path loss on the transmitted image data
out of the brain. A single-chip application-specific integrated circuit (ASIC) is de-
signed to realize the wireless architecture and interface with array elements, each
of which includes a transceiver (TRX) front-end with a high-voltage (HV) pulser,
a high-voltage T/R switch, and a low-noise amplifier (LNA). Novel design techniques are implemented in the system to enhance the performance of its building
blocks.
Apart from imaging capability, the implantable wireless microsystems can include a pressure sensing readout to measure intracranial pressure. To do so, a
power-efficient readout for pressure sensing is presented. It uses pseudo-pseudo
differential readout topology to cut down the static power consumption of the sensor for further power savings in wireless microsystems.
In addition, the effect of matching and electrical termination on CMUT array
elements is explored leading to new interface structures to improve bandwidth
and sensitivity of CMUT arrays in different operation regions. Comprehensive
analysis, modeling, and simulation methodologies are presented for further investigation.Ph.D
Design/cost tradeoff studies. Appendix A. Supporting analyses and tradeoffs, book 1. Earth Observatory Satellite system definition study (EOS)
A listing of the Earth Observatory Satellite (EOS) candidate missions is presented for use as a baseline in describing the EOS payloads. The missions are identified in terms of first, second, and third generation payloads. The specific applications of the EOS satellites are defined. The subjects considered are: (1) orbit analysis, (2) space shuttle interfaces, (3) thematic mapping subsystem, (4) high resolution pointable imager subsystem, (5) the data collection system, (6) the synthetic aperture radar, (7) the passive multichannel microwave radiometer, and (8) the wideband communications and handling equipment. Illustrations of the satellite and launch vehicle configurations are provided. Block diagrams of the electronic circuits are included
Proceedings of the Third International Mobile Satellite Conference (IMSC 1993)
Satellite-based mobile communications systems provide voice and data communications to users over a vast geographic area. The users may communicate via mobile or hand-held terminals, which may also provide access to terrestrial cellular communications services. While the first and second International Mobile Satellite Conferences (IMSC) mostly concentrated on technical advances, this Third IMSC also focuses on the increasing worldwide commercial activities in Mobile Satellite Services. Because of the large service areas provided by such systems, it is important to consider political and regulatory issues in addition to technical and user requirements issues. Topics covered include: the direct broadcast of audio programming from satellites; spacecraft technology; regulatory and policy considerations; advanced system concepts and analysis; propagation; and user requirements and applications
Software Defined Radio using MATLAB & Simulink and the RTL-SDR
The availability of the RTL-SDR for less than $20 brings SDR to the home and work desktops of EE students, professional engineers and the maker community. The RTL-SDR device can be used to acquire and sample RF (radio frequency) signals transmitted in the frequency range 25MHz to 1.75GHz, and using some official software add-ons, these samples can be brought into the MATLAB and Simulink environment for users to develop receivers using first principles DSP algorithms. Signals that the RTL-SDR hardware can receive include: FM radio, UHF band signals, ISM signals, GSM, 3G and LTE mobile radio, GPS and satellite signals, and any that the reader can (legally) transmit of course! In this free book we introduce readers to SDR methods by viewing and analysing downconverted RF signals in the time and frequency domains, and then provide extensive DSP enabled SDR design exercises which the reader can learn from. The hands-on examples begin with simple AM and FM receivers, and move on to the more challenging aspects of PHY layer DSP, where receive filter chains, real-time channelisers, and advanced concepts such as carrier synchronisers, digital PLL designs and QPSK timing and phase synchronisers are implemented. Towards the end of the book, we demonstrate how the RTL-SDR can be used with SDR transmitters to develop a more complete communications system, capable of transmitting text strings and images across the desktop
Proceedings of the Fifth International Mobile Satellite Conference 1997
Satellite-based mobile communications systems provide voice and data communications to users over a vast geographic area. The users may communicate via mobile or hand-held terminals, which may also provide access to terrestrial communications services. While previous International Mobile Satellite Conferences have concentrated on technical advances and the increasing worldwide commercial activities, this conference focuses on the next generation of mobile satellite services. The approximately 80 papers included here cover sessions in the following areas: networking and protocols; code division multiple access technologies; demand, economics and technology issues; current and planned systems; propagation; terminal technology; modulation and coding advances; spacecraft technology; advanced systems; and applications and experiments
Abstracts on Radio Direction Finding (1899 - 1995)
The files on this record represent the various databases that originally composed the CD-ROM issue of "Abstracts on Radio Direction Finding" database, which is now part of the Dudley Knox Library's Abstracts and Selected Full Text Documents on Radio Direction Finding (1899 - 1995) Collection. (See Calhoun record https://calhoun.nps.edu/handle/10945/57364 for further information on this collection and the bibliography).
Due to issues of technological obsolescence preventing current and future audiences from accessing the bibliography, DKL exported and converted into the three files on this record the various databases contained in the CD-ROM.
The contents of these files are:
1) RDFA_CompleteBibliography_xls.zip [RDFA_CompleteBibliography.xls: Metadata for the complete bibliography, in Excel 97-2003 Workbook format; RDFA_Glossary.xls: Glossary of terms, in Excel 97-2003 Workbookformat; RDFA_Biographies.xls: Biographies of leading figures, in Excel 97-2003 Workbook format];
2) RDFA_CompleteBibliography_csv.zip [RDFA_CompleteBibliography.TXT: Metadata for the complete bibliography, in CSV format; RDFA_Glossary.TXT: Glossary of terms, in CSV format; RDFA_Biographies.TXT: Biographies of leading figures, in CSV format];
3) RDFA_CompleteBibliography.pdf: A human readable display of the bibliographic data, as a means of double-checking any possible deviations due to conversion
Design and analysis of wideband passive microwave devices using planar structures
A selected volume of work consisting of 84 published journal papers is presented to demonstrate the contributions made by the author in the last seven years of his work at the University of Queensland in the area of Microwave Engineering. The over-arching theme in the author’s works included in this volume is the engineering of novel passive microwave devices that are key components in the building of any microwave system. The author’s contribution covers innovative designs, design methods and analyses for the following key devices and associated systems: Wideband antennas and associated systems Band-notched and multiband antennas Directional couplers and associated systems Power dividers and associated systems Microwave filters Phase shifters Much of the motivation for the work arose from the desire to contribute to the engineering o
Digital compensation of lowpass filters imperfection in the Modulated Wideband Converter compressed sensing scheme for radio frequency monitoring
International audienceThis paper focuses on non-ideal filters in a Modulated Wideband Converter (MWC) scheme. The MWC is a system that can sample a sparse wideband signal at sub-Nyquist rate. Generally, the output of the ideal MWC components will ensure a perfect reconstruction. In practice, the reconstruction should be based on the output of non-ideal components, especially filters. The impact of non-ideal filters will trigger to a bad reconstruction. In this paper, a detailed study on non-ideal lowpass filters imperfection used in compressed sensing MWC scheme is synthesized. A digital post-treatment scheme with amplitude and phase compensation is proposed after real lowpass filtering step in order to have the filtered output as close as the ideal lowpass filter output. At last, reconstruction spectra obtained from different simulated lowpass filters are compared with different parameters of MWC