336 research outputs found
Boundary scan system design
Given the strong competition in digital design on the national and international levels, boundary scan devices are rapidly becoming a necessary as opposed to a convenient feature on integrated circuits. This thesis serves a dual purpose. First, it demonstrates how boundary scan devices can be used to increase the testability of a circuit and it presents several factors used to quantify the cost associated with the addition of boundary scan compatibility to digital designs. Cost tradeoffs are often the most intimidating hurdle for engineers to cross when deciding if boundary scan compatibility is worth the effort. Second, it demonstrates the use of the Tektronix LV500 (logic verifier) as a general testing tool, using boundary scan designs as examples. These examples provide an understanding of the function of boundary scan cells and the JTAG/1 149. 1 standard. The LV500, which is used by students in the Department of Computer Engineering and Microelectronic Engineering at RIT, is an indispensable tool for making critical timing measurements. It also allows a user to evaluate and step through simple as well as more complicated designs. It is my hope that this thesis and the tutorial provided will facilitate the use of the LV500 in future testing work performed in RIT\u27s center for Microelectronic and Computer Engineering clean room facilities. Upon following the example circuits described, one should become familiar with boundary scan terminology as well as the methodology used in designing such a system
Using Numerical Dynamic Programming to Compare Passive and Active Learning in the Adaptive Management of Nutrients in Shallow Lakes
This paper illustrates the use of dual/adaptive control methods to compare passive and active adaptive management decisions in the context of an ecosystem with a threshold effect. Using discrete-time dynamic programming techniques, we model optimal phosphorus loadings under both uncertainty about natural loadings and uncertainty regarding the critical level of phosphorus concentrations beyond which nutrient recycling begins. Active management is modeled by including the anticipated value of information (or learning) in the structure of the problem, and thus the agent can perturb the system (experiment), update beliefs, and learn about the uncertain parameter. Using this formulation, we define and value optimal experimentation both ex ante and ex post. Our simulation results show that experimentation is optimal over a large range of phosphorus concentration and belief space, though ex ante benefits are small. Furthermore, realized benefits may critically depend on the true underlying parameters of the problem.adaptive control, adaptive management, dynamic programming, value of experimentation, value of information, nonpoint source pollution, learning, decisions under uncertainty, Resource /Energy Economics and Policy,
CCD Readout Electronics for the Subaru Prime Focus Spectrograph
We present details of the design for the CCD readout electronics for the
Subaru Telescope Prime Focus Spectrograph (PFS). The spectrograph is comprised
of four identical spectrograph modules, each collecting roughly 600 spectra.
The spectrograph modules provide simultaneous wavelength coverage over the
entire band from 380 nm to 1260 nm through the use of three separate optical
channels: blue, red, and near infrared (NIR). A camera in each channel images
the multi-object spectra onto a 4k x 4k, 15 um pixel, detector format. The two
visible cameras use a pair of Hamamatsu 2k x 4k CCDs with readout provided by
custom electronics, while the NIR camera uses a single Teledyne HgCdTe 4k x 4k
detector and ASIC Sidecar to read the device.
The CCD readout system is a custom design comprised of three electrical
subsystems: the Back End Electronics (BEE), the Front End Electronics (FEE),
and a Pre-amplifier. The BEE is an off-the-shelf PC104 computer, with an
auxiliary Xilinx FPGA module. The computer serves as the main interface to the
Subaru messaging hub and controls other peripheral devices associated with the
camera, while the FPGA is used to generate the necessary clocks and transfer
image data from the CCDs. The FEE board sets clock biases, substrate bias, and
CDS offsets. It also monitors bias voltages, offset voltages, power rail
voltage, substrate voltage and CCD temperature. The board translates LVDS clock
signals to biased clocks and returns digitized analog data via LVDS. Monitoring
and control messages are sent from the BEE to the FEE using a standard serial
interface. The Pre-amplifier board resides behind the detectors and acts as an
interface to the two Hamamatsu CCDs. The Pre-amplifier passes clocks and biases
to the CCDs, and analog CCD data is buffered and amplified prior to being
returned to the FEE.Comment: 14 pages, 15 figures, SPIE ATI 2014, Montrea
Visible camera cryostat design and performance for the SuMIRe Prime Focus Spectrograph (PFS)
We describe the design and performance of the SuMIRe Prime Focus Spectrograph
(PFS) visible camera cryostats. SuMIRe PFS is a massively multi-plexed
ground-based spectrograph consisting of four identical spectrograph modules,
each receiving roughly 600 fibers from a 2394 fiber robotic positioner at the
prime focus. Each spectrograph module has three channels covering wavelength
ranges 380~nm -- 640~nm, 640~nm -- 955~nm, and 955~nm -- 1.26~um, with the
dispersed light being imaged in each channel by a f/1.07 vacuum Schmidt camera.
The cameras are very large, having a clear aperture of 300~mm at the entrance
window, and a mass of 280~kg. In this paper we describe the design of the
visible camera cryostats and discuss various aspects of cryostat performance
Data Reduction Pipeline for the CHARIS Integral-Field Spectrograph I: Detector Readout Calibration and Data Cube Extraction
We present the data reduction pipeline for CHARIS, a high-contrast
integral-field spectrograph for the Subaru Telescope. The pipeline constructs a
ramp from the raw reads using the measured nonlinear pixel response, and
reconstructs the data cube using one of three extraction algorithms: aperture
photometry, optimal extraction, or fitting. We measure and apply both
a detector flatfield and a lenslet flatfield and reconstruct the wavelength-
and position-dependent lenslet point-spread function (PSF) from images taken
with a tunable laser. We use these measured PSFs to implement a -based
extraction of the data cube, with typical residuals of ~5% due to imperfect
models of the undersampled lenslet PSFs. The full two-dimensional residual of
the extraction allows us to model and remove correlated read noise,
dramatically improving CHARIS' performance. The extraction produces a
data cube that has been deconvolved with the line-spread function, and never
performs any interpolations of either the data or the individual lenslet
spectra. The extracted data cube also includes uncertainties for each spatial
and spectral measurement. CHARIS' software is parallelized, written in Python
and Cython, and freely available on github with a separate documentation page.
Astrometric and spectrophotometric calibrations of the data cubes and PSF
subtraction will be treated in a forthcoming paper.Comment: 18 pages, 15 figures, 3 tables, replaced with JATIS accepted version
(emulateapj formatted here). Software at
https://github.com/PrincetonUniversity/charis-dep and documentation at
http://princetonuniversity.github.io/charis-de
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