Alessandro Mortara

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An architecture for interchip communication among analog VLSI neural networks is proposed. Activity is encoded in a neuron's pulse emission frequency. Information is transmitted through the non-arbitered, asynchronous access of pulses to a common bus. The impact of collisions when the bus is accessed by more than one user is investigated. The(More)
A 100 100 pixel analog very large scale integration retina is proposed to extract the magnitude and direction of spatial gradients contained in sensed images. The retina implements in a massively parallel fashion, at pixel level, an algorithm based on the concept of steerable filters to compute the gradients. An output rate of up to 1000 frames per second(More)
Pulse frequency modulation (PFM) provides robust long-distance communication and event-driven access to the communication channel. A PFM demodulator small and simple enough to equip every cell of a large analog neural network is analyzed. The circuit can demodulate PFM signals with pulse rates as low as 1 kHz using the switched-capacitor technique.(More)
It is widely held that the spatial resolution achievable by NMR microscopic imaging is limited in biological systems by diffusion to approximately 1-5 microns. However, these estimates were developed for specific imaging techniques and represent practical rather than fundamental limits. NMR imaging is limited by the signal-to-noise ratio (SNR). Diffusion(More)
This paper describes a Josephson-voltage-standardlocked synthesizer where a commercial digital-to-analog converter is used as a sine wave generator. The output amplitude of the generator is controlled by the calculable fundamental of the stepwise waveform generated by a SINIS Josephson junction array. Such a system combines the versatility of a commercial(More)
The low-ohmic resistance measurement capabilities of the Van Swinden Laboratorium, National Institute of Standards and Technology, and the Federal Office of Metrology (METAS) were compared using a set of resistors with values 100 mΩ, 10 mΩ, 1 mΩ, and 100 μΩ, respectively. The measurement results of the three laboratories agree extremely well within the(More)
The working principle and the architecture of a calibration system for devices operating with the IEC 61850-9-2 standard are described. Two different types of devices are considered: stand-alone merging units (SAMUs) used to retrofit conventional transformers in power network substations and commercial test sets suited for nonconventional voltage and(More)
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