6 research outputs found
Design of clock and data recovery circuits for energy-efficient short-reach optical transceivers
Nowadays, the increasing demand for cloud based computing and social media
services mandates higher throughput (at least 56 Gb/s per data lane with 400
Gb/s total capacity 1) for short reach optical links (with the reach typically less
than 2 km) inside data centres. The immediate consequences are the huge
and power hungry data centers. To address these issues the intra-data-center
connectivity by means of optical links needs continuous upgrading.
In recent years, the trend in the industry has shifted toward the use of more
complex modulation formats like PAM4 due to its spectral efficiency over the
traditional NRZ. Another advantage is the reduced number of channels count
which is more cost-effective considering the required area and the I/O density.
However employing PAM4 results in more complex transceivers circuitry due
to the presence of multilevel transitions and reduced noise budget. In addition,
providing higher speed while accommodating the stringent requirements
of higher density and energy efficiency (< 5 pJ/bit), makes the design of the
optical links more challenging and requires innovative design techniques both
at the system and circuit level.
This work presents the design of a Clock and Data Recovery Circuit (CDR) as
one of the key building blocks for the transceiver modules used in such fibreoptic
links. Capable of working with PAM4 signalling format, the new proposed
CDR architecture targets data rates of 50â56 Gb/s while achieving the required
energy efficiency (< 5 pJ/bit).
At the system level, the design proposes a new PAM4 PD which provides a better
trade-off in terms of bandwidth and systematic jitter generation in the CDR. By
using a digital loop controller (DLC), the CDR gains considerable area reduction
with flexibility to adjust the loop dynamics.
At the circuit level it focuses on applying different circuit techniques to mitigate
the circuit imperfections. It presents a wideband analog front end (AFE),
suitable for a 56 Gb/s, 28-Gbaud PAM-4 signal, by using an 8x interleaved, master/
slave based sample and hold circuit. In addition, the AFE is equipped with
a calibration scheme which corrects the errors associated with the sampling
channelsâ offset voltage and gain mismatches. The presented digital to phase
converter (DPC) features a modified phase interpolator (PI), a new quadrature
phase corrector (QPC) and multi-phase output with de-skewing capabilities.The DPC (as a standalone block) and the CDR (as the main focus of this work)
were fabricated in 65-nm CMOS technology. Based on the measurements, the
DPC achieves DNL/INL of 0.7/6 LSB respectively while consuming 40.5 mW
power from 1.05 V supply. Although the CDR was not fully operational with
the PAM4 input, the results from 25-Gbaud PAM2 (NRZ) test setup were used
to estimate the performance. Under this scenario, the 1-UI JTOL bandwidth
was measured to be 2 MHz with BER threshold of 10â4. The chip consumes 236
mW of power while operating on 1 â 1.2 V supply range achieving an energyefficiency
of 4.27 pJ/bit
Topical Workshop on Electronics for Particle Physics
The purpose of the workshop was to present results and original concepts for electronics research and development relevant to particle physics experiments as well as accelerator and beam instrumentation at future facilities; to review the status of electronics for the LHC experiments; to identify and encourage common efforts for the development of electronics; and to promote information exchange and collaboration in the relevant engineering and physics communities
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
High Energy Physics
This grant covered an umbrella program of research in high-Ââenergy particle physics at Southern Methodist University during the period 2004-Ââ2013. The experimental program evolved during that time. At its early stages it included research on the CLEO experiment at CESR (Coan, Stroynowski, Ye), D0 experiment at Tevatron (Kehoe), preparation for the BTEV experiment at Fermilab (Coan) and construction and commissioning of the Liquid Argon Calorimeter for the ATLAS experiment at LHC (Stroynowski, Ye). In the last three years the program concentrated on the ATLAS experiment at LHC (Kehoe, Sekula, Stroynowski, Ye), D0 experiment at Tevatron (Kehoe) and NOvA experiment at Fermilab (Coan). Professor Sekula had a short-Ââterm independent grant for which he is submitting a separate report. The theoretical physics program included work on non-Ââperturbative methods in the light cone representation (McCartor (deceased)), lattice calculations (Hornbostel), and determination of parton distribution functions (Olness). A summary of the accomplishments emphasizing results from the past three years is provided separately for each of the tasks