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Improving timing verification and delay testing methodologies for IC designs
textThe task of ensuring the correct temporal behavior of IC designs,
both before and after fabrication, is extremely important. It is becoming
even more imperative as the demand for performance increases and process
technology advances into the deep sub-micron region.
This dissertation tackles the key issues in the timing verification
and delay testing methodologies. An efficient methodology is presented to
identify false timing paths in the timing verification methodology which utilizes
ATPG technique and timing information from an ordered list of timing
paths according to the delay information. This dissertation also presents a
speed binning methodology which utilizes structural delay tests successfully
instead of functional tests. In addition, it establishes a methodology which
quantifies the correlation between the timing verification prediction and
actual silicon measurement of timing paths. This quantification methodology
lays the foundation for further research to study the impact of deep
submicron effects on design performanceElectrical and Computer Engineerin
Choose-Your-Own Adventure: A Lightweight, High-Performance Approach To Defect And Variation Mitigation In Reconfigurable Logic
For field-programmable gate arrays (FPGAs), fine-grained pre-computed alternative configurations, combined with simple test-based selection, produce limited per-chip specialization to counter yield loss, increased delay, and increased energy costs that come from fabrication defects and variation. This lightweight approach achieves much of the benefit of knowledge-based full specialization while reducing to practical, palatable levels the computational, testing, and load-time costs that obstruct the application of the knowledge-based approach. In practice this may more than double the power-limited computational capabilities of dies fabricated with 22nm technologies.
Contributions of this work:
• Choose-Your-own-Adventure (CYA), a novel, lightweight, scalable methodology to achieve defect and variation mitigation
• Implementation of CYA, including preparatory components (generation of diverse alternative paths) and FPGA load-time components
• Detailed performance characterization of CYA
– Comparison to conventional loading and dynamic frequency and voltage scaling (DFVS)
– Limit studies to characterize the quality of the CYA implementation and identify potential areas for further optimizatio
Investigation of a piezo-polymer array transducer for pulse-echo ultrasonic material examinations
The aim of this investigation was to make a flexible array of
pulse-echo ultrasound transducers by etching two orthogonal linear
arrays of conducting elements into the metallisation of either side of
a sheet of PVdF. These would then be multiplexed under computer
control in an X-Y raster, thereby forming an image of subsurface
defects in a material specimen.
A potential source model was used to predict the sensitivity
of a single element air-backed transducer far from resonance. Initial
investigations confirmed the predictions, and reaffirmed the results
of previous workers.
In making a prototype array, it was found necessary to use a
bi-laminar arrangement with a central ground plane, due to
difficulties with crosstalk and charge leakage into the specimen
materials. The radiation pattern of this array was tested and found
to agree with the predictions for Fraunhofer (Far-Field) radiation.
A 10 MHz analogue to digital converter was constructed to
interface with the IBM-PC clone as a transient recorder, through a
data capture program written in 'C'. However, the electrical noise
generated by the PC was found to interfere strongly with the signal
from the array transducer.
A wide-band amplifier and full-wave rectifier was then added
to the multiplexer and A/D converter, and the system enclosed in an
electrically isolated environment, which made it possible to obtain
clear signal data from the transducer.
Non-linear regression was implemented in the software, to
smooth the data and locate echo peaks, and the most frequently
occurring peak separation was used to indicate sample thickness at
that location in a false-colour mapping on the screen of the PC
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