Laurentiu Ionescu

FPGA Implementations of Cellular Automata for Pseudo-Random Number Generation

This paper present a hardware implementation in a FPGA circuit of an efficient pseudo-random number generator based on cellular automata. We demonstrate in this paper how microscopic (local) interactions influence the overall macroscopic (global) behavior of the whole system. We highlight the possibility to build the evolutionary systems on such a simple mathematical model as a cellular automata space by introducing the rules of evolution of individuals, their interaction, and their robustness to variations of the model. A regular, modular, and cascadable hardware implementation of the generator has been implemented, which is efficient in terms of VLSI technology. The design has been specified in VHDL targeted on a XC3S400 based FPGA and verified for functional correctness by software simulation

Detecting errors in digital communications with CRC codes implemented with FPGA

Generally speaking, cyclic redundancy checks (CRCs) are used to detect errors from noise in digital data transmission. The technique is also sometimes applied to data storage devices, such as a disk drive. They also have been turned to verify the integrity of files in a system in order to prevent tampering and suggested as a possible algorithm for manipulation detection codes. It has been known that a CRC will not detect all errors but with random noise it is unlikely. In this paper, we present an efficient algorithm for parallel computation of the CRC in data transmission.

Error detection and correction using LDPC in parallel Hopfield networks

Low Density Parity Check (LDPC) coding is a classical method for the detection and correction of errors. Its problem is the relatively complex operations which must be performed at encoding, and especially at decoding, to detect and correct errors caused by communication channels. We present a solution for the errors correction using regular LDPC and Hopfield network-based associative memories. Our solution solves this problem by using an associative memory based on the Hopfield network on the decoding stage, which stores the correct code words. This memory tends to transform the code words received with errors in errors free code words. We improved the ability of the associative memory by storing the code words in a specific format (pairs with their inverses, the constant number of “1” bits). These conditions are met by using LDPC coding. To be viable in communications, which require real-time correction, our proposed solution has used Hopfield networks operating in parallel, fully integrated into the Field Programmable Gates Array (FPGA) circuit.

VLSI implementation of an associative content addressable memory based on Hopfield network model

The content addressable memory (CAM) is allowed to search a data word without knowing where its address is. In addition, it is permissible to associate the content of the location or neighboring locations where the data word was identified. This paper presents our own approach for VLSI hardware implementation of the CAM memory. The proposed solution uses a Hopfield neural network model and is characterized by simplicity and the possibility of using the same hardware structures for saving may data patterns. Will be presented design methods and implementation to VLSI circuit structures, the performance of our solution and experimental results.

Optimization of sigma-delta modulator based on artificial immune algorithms

The artificial immune algorithms are implemented by the human immune system. They inspired a technique that has the ability to find optimal solutions in a nonlinear search space. This kind of technique increases the computing speed and converges faster than the genetic algorithms. In this paper is presented an application of artificial immune algorithms in order to optimize the transfer function of a sigma delta modulator. It is also presented the base method which can perform the adjustment coefficients, in decimal, of the sigma delta modulator. The results are compared with those obtained by the method of optimization based on both mathematical and genetic algorithms.

Remote communication interface for sound and vibration sensors

In this paper are presented the results regarding the implementation of a communication interface dedicated for conditioning and remote transmission of measurement signals acquired from sound and vibration sensors. The interface contains two parts, an analog section, responsible with long distance signal transmission and a digital section that realize demodulation and analog-to-digital conversion of the received signal. The analog part of the interface uses the frequency modulation technique that is well known for its ability to operate in environments characterized by high levels of electrical perturbations, even when are realized high speed data transmissions. The acquisition of signals from sensors is realized with a resolution of 16 bits with a maximum speed of 200kS/s. In order to ensure the compatibility with various communication media and different types of sensors, the proposed circuit has adjustable carrier frequency in the range [0,01 - 0,5] MHz and offers also the possibility to select the carrier signal waveforms: square or sinusoidal wave. In addition, for increased versatility, the communication interface combines two alternative configurations, one based on phase-locked-loop (PLL) structure and the second based on quadrature oscillator with analogue multipliers. Both configurations were thoroughly tested for evaluating the performances of the proposed design. In comparison with other structures, the remote communication interface proposed in this work revealed good stability, accuracy and reliability. Also, the robustness and simplicity of the interface due to the use of frequency modulation technique represent other significant advantages.

Real time system for instrumental sound extraction and recognition

This article presents a “smart sound sensor” solution. More specifically it is a system on a chip capable of extracting sound patterns from an input signal captured by a microphone, patterns that correspond to certain musical instruments. The aim is to identify sounds like: voices, ambient sounds or musical sounds. Such applications generally involve the presence of a computer that analyzes offline the audio sequence. There are also smartphone security applications that rely on voice recognition templates that were previously stored and which work by processing the input sequence offline, after recording. Unlike these methods, our solution enables online real time identification of a group of musical instruments and allows extracting of certain sound sequences that belong to a particular instrument so that it can be isolated for sole playing. The solution was implemented in an integrated system “sound sensor” that analyzes the input signal in real time and can give output data without additional elements.

Indoor Broadcasting System for Personalized TV Emissions Addressed to Tele-Assisted Persons

Abstract The category of peoples that need tele-assistance includes persons with special needs (i.e. elderly, chronics, etc.) whose life style should be monitored and guided according to personalized plans. In this paper we propose a system for remote control of the TV-sets in a residence so that they become able to receive and display some thematic programs running on an embedded PC, which is generally placed into other room. The system includes two parts: one is dedicated to control remotely the TV-set and other is to transmit the film from PC to TV. A key issue to solve was to assure the remote control of the TV-set by PC without user action involving and also avoiding any modification inside the existent equipments. The proposed solution is based on a special designed relay-translator which manages a radio receiver module and an IR transceiver.

Simulation and implementation of a pulse position modulator for short-range optical communication systems

In this paper are presented the results regarding the simulation and the implementation of an enhanced communication interface based on pulse position modulation technique. The proposed module is aimed for integration in the conditioning circuits of the sensors that are connected to data acquisition systems which require transmission of information signals over short to moderate distances. Because the circuit allows that the optical driver of the transmitter to be operated at high power levels results an increased signal-to-noise ratio and an extended lifetime for the optical source. These advantages make this design particularly suited for the free space laser or optical fiber based data transmission in sensor networks. The novel approach based on variable width carrier pulses allows the control of the frequency spectrum for the transmitted signal and an improved signal-to-noise ratio, these characteristics leading to increased performances for the proposed module. Compared with other circuits based on cable or radio transmission, the optical communication interface presented in this paper represent a very suitable solution for transferring the signals from sensors, because it ensures high immunity to interferences and superior data transfer rates.

Electricity consumption measurement system for detecting losses occurring in power transmission networks

The paper proposes a solution for measuring the current consumption on the transmission lines for detecting the losses that may occur. The solution is non-invasive: the sensors determine the current by analyzing the electric field around the isolated conductor, it is fully mobile and easy to install: sensors are “clamp” type and can be placed on insulated conductors, data is transmitted wirelessly to a local collector that will then transmit it to the server — no installation infrastructure is needed. The solution is also energy-efficient: the sensors and the data transmitter feed from the electric field around the conductor (self-harvesting sensors) while the concentrator (the local data collector) is powered from batteries connected to a photovoltaic panel. The solution will provide data at a central server where it will be analyzed and compared to consumer data (e.g. from smart grid). The assessment of consumption on electricity transmission lines allows: to determine the losses occurring up to the customers current meters, to determine the profile of some consumers and to establish tariff plans according to them, to establish an optimal energy transmission plan from suppliers to consumers. Electricity consumption measurement, self harvesting sensors, non-invasive, wireless networks.