Thomas J. Mozdzen

Power conscious CAD tools and methodologies: a perspective

Power consumption is rapidly becoming an area of growing concern in IC and system design houses. Issues such as battery life, thermal limits, packaging constraints and cooling options are becoming key factors in the success of a product. As a consequence, IC and system designers are beginning to see the impact of power on design area, design speed, design complexity and manufacturing cost. While process and voltage scaling can achieve significant power reductions, these are expensive strategies that require industry momentum, that only pay off in the long run. Technology independent gains for power come from the area of design for low power which has a much higher return on investment (ROI). But low power design is not only a new area but is also a complex endeavour requiring a broad range of synergistic capabilities from architecture/microarchitecture design to package design. It changes traditional IC design from a two-dimensional problem (Area/performance) to a three-dimensional one (Area/Performance/Power). This paper describes the CAD tools and methodologies required to effect efficient design for low power. It is targeted to a wide audience and tries to convey an understanding of the breadth of the problem. It explains the state of the art in CAD tools and methodologies. The paper is written in the form of a tutorial, making it easy to read by keeping the technical depth to a minimum while supplying a wealth of technical references. Simultaneously the paper identifies unresolved problems in an attempt to incite research in these areas. Finally an attempt is made to provide commercial CAD tool vendors with an understanding of the needs and time frames for new CAD tools supporting low power design. >

An absorption profile centred at 78 megahertz in the sky-averaged spectrum

After stars formed in the early Universe, their ultraviolet light is expected, eventually, to have penetrated the primordial hydrogen gas and altered the excitation state of its 21-centimetre hyperfine line. This alteration would cause the gas to absorb photons from the cosmic microwave background, producing a spectral distortion that should be observable today at radio frequencies of less than 200 megahertz. Here we report the detection of a flattened absorption profile in the sky-averaged radio spectrum, which is centred at a frequency of 78 megahertz and has a best-fitting full-width at half-maximum of 19 megahertz and an amplitude of 0.5 kelvin. The profile is largely consistent with expectations for the 21-centimetre signal induced by early stars; however, the best-fitting amplitude of the profile is more than a factor of two greater than the largest predictions. This discrepancy suggests that either the primordial gas was much colder than expected or the background radiation temperature was hotter than expected. Astrophysical phenomena (such as radiation from stars and stellar remnants) are unlikely to account for this discrepancy; of the proposed extensions to the standard model of cosmology and particle physics, only cooling of the gas as a result of interactions between dark matter and baryons seems to explain the observed amplitude. The low-frequency edge of the observed profile indicates that stars existed and had produced a background of Lyman-α photons by 180 million years after the Big Bang. The high-frequency edge indicates that the gas was heated to above the radiation temperature less than 100 million years later.

Area-Efficient Temporally Hardened by Design Flip-Flop Circuits

Two temporally hardened master-slave flip-flops are presented. Both designs utilize master latches containing Muller C-elements and dual redundant temporal hardening, as well as spatially interleaved circuits in both the master and slave latches to obtain large critical node spacing for immunity to multiple node charge collection. Heavy ion test results on the first flip-flop, which uses a DICE slave latch, demonstrates effectiveness of the temporal hardening approach. The second design uses a temporally hardened slave latch, which also hardens the flip-flop against clock transients. The use of automated CAD synthesis and layout techniques using these multibit flip-flops is also described, as is the hardening impact on design size and power.

Radiometric measurements of electron temperature and opacity of ionospheric perturbations

Changes in the sky noise spectrum are used to characterize perturbations in the ionosphere. Observations were made at the same sidereal time on multiple days using a calibrated broadband dipole and radio spectrometer covering 80 to 185 MHz. In this frequency range, an ionospheric opacity perturbation changes both the electron thermal emission from the ionosphere and the absorption of the sky noise background. For the first time, these changes are confirmed to have the expected spectral signature and are used to derive the opacity and electron temperature associated with the perturbations as a function of local time. The observations were acquired at the Murchison Radio-astronomy Observatory in Western Australia from 18 April 2014 to 6 May 2014. They show perturbations that increase at sunrise, continue during the day, and decline after sunset. Magnitudes corresponding to an opacity perturbation of about 1% at 150 MHz with a typical electron temperature of about 800 K were measured for the strongest perturbations.

CALIBRATION OF THE EDGES HIGH-BAND RECEIVER TO OBSERVE THE GLOBAL 21 cm SIGNATURE FROM THE EPOCH OF REIONIZATION

The EDGES High-Band experiment aims to detect the sky-average brightness temperature of the

Temporal sequential logic hardening by design with a low power delay element

21

Ultra-thin gate-oxide characteristics and MOS/VLSI scaling implications

-cm signal from the Epoch of Reionization (EoR) in the redshift range

One-Port Direct/Reverse Method for Characterizing VNA Calibration Standards

14.8 \gtrsim z \gtrsim 6.5

Nosie and signal integrity in deep submicron design (panel)

. To probe this redshifted signal, EDGES High-Band conducts single-antenna measurements in the frequency range

Decoupling capacitance study and optimization method for high-performance VLSIs

90-190