Stefano Bertazzoni

Parallel hardware implementation of radar electronics equipment for a laser inspection system

An amplitude modulated laser radar has been developed by ENEA (Italian Agency for new technologies, energy and environment) for periodic in-vessel inspection in large fusion machines (ITER). The system is able to obtain a complete 3D mapping of the in-vessel surface. First, a digital signal processing system was developed to modulate the laser beam and to detect both the amplitude of the back scattered light and the phase difference between it and the modulation signal. This system is based on commercial digital receiver and parallel DSP (digital signal processing) boards on a VME bus. It reaches a speed of 100 K measures/s showing good accuracy and stability. Starting from this, further development has been done to increase the speed up to 2.328 M measures/s. To reach the sub-microsecond speed it was necessary to implement the mathematical algorithm in a highly parallel hardware architecture using FPGAs (field programmable gate array). Looking at the good results of previously developed system it was decided to maintain the same acquisition front-end. The last release of A/D converters was used to increase the operating frequency up to 200 MHz, but the previously used software algorithm was completely redesigned and optimized to be used in the FPGA hardware architecture.

Parallel hardware implementation of RADAR electronics equipment for a LASER inspection system

An amplitude modulated laser radar has been developed by the Italian Agency for New Technologies, Energy and the Environment for periodic in-vessel inspection in large fusion machines (International Thermonuclear Experimental Reactor). The system is able to obtain a complete three-dimensional mapping of the in-vessel surface. A first digital signal processing system was developed to modulate the laser beam and to detect both the amplitude of the backscattered light and the phase difference between it and the modulation signal. This system is based on commercial digital receiver and parallel digital signal processing boards on a VME bus. It reaches a speed of 100 K measures/s, showing good accuracy and stability. Starting from this, a further development has been done to increase the speed up to 2.328 M measures/s. Reaching the submicrosecond speed was necessary to implement the mathematical algorithm in a highly parallel hardware architecture using a field programmable gate array (FPGA). Based on the good results of the previously developed system, it was decided to maintain the same acquisition front-end though using the last release of analog-to-digital converters, to increase the operating frequency from 80 up to 200 MHz. The software algorithm previously used was completely redesigned and optimized to be used in the FPGA hardware architecture

Short term local meteorological forecasting using type-2 fuzzy systems

Meteorological forecasting is an important issue in research. Typically, the forecasting is performed at “global level,” by gathering data in a large geographical region and by studying their evolution, thus foreseeing the meteorological situation in a certain place. In this paper a “local level” approach, based on time series forecasting using Type-2 Fuzzy Systems, is proposed. In particular temperature forecasting is inspected. The Fuzzy System is trained by means of historical local time series. The algorithm uses a detrend procedure in order to extract the chaotic component to be predicted.

Failure tests on 64 Mb SDRAM in radiation environment

In this paper we analyze the failures of Commercial Off The Shelf (COTS) 64 Mb Synchronous DRAM (SDRAM) in a radiation environment. The experimental setup, the test procedure, and the results of three different test runs at the Catania LNS-INFN cyclotron are described in some detail. Three kinds of heavy ions were used to test devices under different conditions of energy release that generates different amount of charge inside the chip. In particular, 30 MeV/AMU /sup 93/Nb (LET/sub Si//spl sim/21 MeV/(mg/cm/sup 2/), R/sub Si//spl sim/397 /spl mu/m), 30 MeV/AMU /sup 120/Sn (LET/sub Si//spl sim/30 MeV/(mg/cm/sup 2/), R/sub Si//spl sim/370 /spl mu/m) and 15 MeV/AMU /sup 197/Au (LET/sub Si//spl sim/90 MeV/(mg/cm/sup 2/), R/sub Si//spl sim/95 /spl mu/m) were used. In all cases, the bare dies were directly bonded on an AF4 carrier to avoid plastic and lead-frame shielding. Different failure types that could affect the operations of a system based on this device were registered. To verify that the characteristics of the events depend on the zone struck by the particle, a specific test was performed.

16-point high speed (I)FFT for OFDM modulation

In this paper we present the implementation of a 16-point (I)FFT ((Inverse) Fast Fourier Transform) with 24-bit complex data precision suitable for OFDM applications. The die measures 3.2/spl times/3.3 mm/sup 2/ and is fabricated in double metal 0.7 /spl mu/m ES2 CMOS technology. Our algorithm does not use any multiplier allowing a throughput up to 85 MWord/s and reducing the core area to less than 5 mm/sup 2/. It is also possible to implement a 256-point (I)FFT using two 16-point devices and a complex multiplier.

Ion Impact Detection and Micromapping With a SDRAM for IEEM Diagnostics and Applications

Ion electron emission microscopy (IEEM) can provide an alternative approach to microbeams for micrometric characterization of the sensitivity map to single event effects (SEE) of an electronic device. In IEEM technique, a broad (not focused) ion beam is sent onto the device under test (DUT). Secondary electrons emitted by the target surface during each ion impact are collected and focused by a system of electrostatic lenses and finally imaged by a high-rate and high-resolution position detector. We will report on the IEEM working at the SIRAD irradiation facility located at the 15 MV Tandem of INFN Legnaro National Laboratories. To estimate the IEEM resolution, a SDRAM is a good candidate to be used as a reference target, thanks to the micrometric feature size of the array of memory cells and the precise knowledge of their physical locations. Since an electronic device is not a good secondary electrons emitter, to ensure a copious and uniform emission of secondary electrons from the DUT, a very thin (100 nm) self-standing silicon nitride (Si3N4) membrane with a Au deposition (40 nm) is mounted on the top of the SDRAM. The Au/Si3N4 membrane and the underlying SDRAM are irradiated with a heavy ion beam. The physical map of ion impacts detected by the SDRAM is then compared with the one reconstructed by the IEEM in the same 500 ms time interval.

High Spectral Purity Digital Direct Synthesizer Implementation by means of a Fuzzy Approximator

Abstract Fuzzy systems are used in many applications because of their implementation simplicity both in software and in hardware. Some papers in literature have shown the behavior of SISO fuzzy systems as function approximators. If the approximation function have certain analytical properties, it can be used to develop interesting solutions of classical problems. In particular, the authors have studied a new method suitable to implement systems whose behavior is described through a function having the derivative continuity. This paper shows how this approach can be used to implement a sinusoidal wave synthesizer that is the core of the digital direct synthesizers (DDS), widely used in modern communications and measurements devices. This work presents how tuning the fuzzy system in order to achieve a very clean sinusoidal wave in output. Both the theoretical behavior of the algorithm and the performance taking into account the errors due to the fixed point arithmetic have been inspected in detail. The results of the simulations and those obtained from the hardware implementation of the device show excellent features especially in the case that a very high spectral purity is required.

TID test for SDRAM based IEEM calibration system

Traditionally, to map out device sensitivity with submicrometric resolutions one uses a microbeam. Ion electron emission microscopy (IEEM) appears to be a promising new method for device characterization. An advanced implementation of this instrument is under development at the SIRAD irradiation facility of the Legnaro National Laboratory (LNL). In IEEM operations total integrated dose (TID) effects could be a potential problem and should be addressed before the final test. For this purpose a TID monitoring method, based on the measurement of the bit retention time, that is the time the information is retained in a memory cell without refresh, in synchronous dynamic RAM (SDRAM) commercial off the shelf (COTS) devices, is proposed. This paper presents the experimental setup and the results of a preliminary TID test with a /sup 60/Co gamma ray source on SDRAM COTS to test the method.