Hardware Discrete Channel Emulator

International audienceIn this paper, the emulation environment named Hardware Discrete Channel Emulator (HDCE) has been developed as a coherent framework to emulate on a hardware device (FPGA as the implementation platform in the verification) and simulate on a computer the effect of an Additive White Gaussian Noise (AWGN) in a base band channel. The HDCE is able to generate more than 180 M samples per second for a very low hardware cost, which has been achieved in an efficient architecture. Using the HDCE, the performance evaluation of a coding scheme for a BER of 10−9 requires only one minute of emulation time

Crystal Structure Manipulation of the Exchange Bias in an Antiferromagnetic Film

Exchange bias is one of the most extensively studied phenomena in magnetism, since it exerts a unidirectional anisotropy to a ferromagnet (FM) when coupled to an antiferromagnet (AFM) and the control of the exchange bias is therefore very important for technological applications, such as magnetic random access memory and giant magnetoresistance sensors. In this letter, we report the crystal structure manipulation of the exchange bias in epitaxial hcp Cr2O3 films. By epitaxially growing twined (10-10) oriented Cr2O3 thin films, of which the c axis and spins of the Cr atoms lie in the film plane, we demonstrate that the exchange bias between Cr2O3 and an adjacent permalloy layer is tuned to in-plane from out-of-plane that has been observed in (0001) oriented Cr2O3 films. This is owing to the collinear exchange coupling between the spins of the Cr atoms and the adjacent FM layer. Such a highly anisotropic exchange bias phenomenon is not possible in polycrystalline films.Comment: To be published in Scientific Reports, 12 pages, 6 figure

A Space-Time Redundancy Technique for Embedded Stochastic Error Correction

International audienceAn error-correction algorithm, referred as to Low Density Parity Check (LDPC) stochastic decoding technique, has recently been introduced for implementing iterative LDPC decoders in logic technologies with a high rate of transient faults. In this work, a modified algorithm that includes a feedback mechanism is first presented. A temporal majority logic is also applied at the decoder's output, providing an additional dimension of redundancy. By comparison to Gallager-A decoding method, the combination of feedback with temporal redundancy is shown to significantly increase the decoder's resilience against a high rate of internal upsets as a gain of up to three orders of magnitude

Observation of long phase-coherence length in epitaxial La-doped CdO thin films

The search for long electron phase coherence length, which is the length that an electron can keep its quantum wave-like properties, has attracted considerable interest in the last several decades. Here, we report the long phase coherence length of ~ 3.7 micro meters in La-doped CdO thin films at 2 K. Systematical investigations of the La doping and the temperature dependences of the electron mobility and the electron phase coherence length reveal contrasting scattering mechanisms for these two physical properties. Furthermore, these results show that the oxygen vacancies could be the dominant scatters in CdO thin films that break the electron phase coherence, which would shed light on further investigation of phase coherence properties in oxide materials.Comment: 13 pages, 6 figure. SI: 8 pages. To appear in Phys. Rev.

Techniques and Prospects for Fault-tolerance in Post-CMOS ULSI

International audienceThis paper presents a survey of fault-masking techniques suitable for tolerating short-duration transient upsets in minimum-scale switching devices. Two types of fault masking are considered. The first type, coded dual-modular redundancy (cDMR), represents a family of parity-checking methods suitable for correcting a low rate of transient upsets. The second type, Restorative Feedback (RFB), is a triple-modular solution suitable for compensating a higher rate of transient upsets. We show that cDMR can be used efficiently for crossbar-style logic, but is not efficient in general for all logic styles. By contrast, RFB offers a fixed redundancy, and can be applied in general to any logic circuit. Finally, we propose novel circuits for ternary Muller C implementation based on carbon nanotube FET devices