8 documents found, page 1 of 1
Bandwidth aspects in second generation current conveyors
Alves, Luis Nero; Aguiar, Rui L.; Santos, Dinis M.This paper discusses bandwidth problems associated with second–generation current conveyors. In particular, our work is centered in high-capacitance applications, especially for wireless optical links and applied physics. We discuss techniques for improving bandwidth in these CCII, and develop a new CCII structure with larger bandwidth than traditional circuits. These circuits are then compared in terms of thei...
Electronic circuits for wireless optical LANs - I
Aguiar, Rui L.; Tavares, António; Cura, José Luis; Vasconcelos, Eduardo de; Alves, Luis Nero; Valadas, Rui; Santos, Dinis M.This is the first of two papers discussing practical issues and results on the implementation of low-cost transceivers for several wireless optical LANs, covering most physical layer elements. Target optical LANs under consideration have bit-rates varying between 4Mbps and 25Mbps, and input photodiode capacitance may vary between 10pF and 50pF. PPM modulation, either in a 4-PPM or 16-PPM format, istypically use...
Electronic circuits for wireless optical LANs - II
Aguiar, Rui L.; Tavares, António; Cura, José Luis; Vasconcelos, Eduardo de; Alves, Luis Nero; Valadas, Rui; Santos, Dinis M.This is the second of two papers discussing practical issues and results on the implementation of low-cost transceivers for several wireless optical LANs, covering most physical layer elements. Target optical LANs under consideration have bit-rates varying between 4Mbps and 25Mbps, and input photodiode capacitance may vary between 10pF and 50pF. PPM modulation, either in a 4-PPM or 16-PPM format, is typically u...
A CMOS signal to noise measurement circuit for infrared sectored receivers
Alves, Luís Nero; Aguiar, Rui L.; Santos, Dinis M.This paper describes a circuit able to measure Signal to Noise ratios developed for Infrared applications. The Signal to Noise ratio is of major importance in IR Sectored Receivers because it provides the basis of selection or combining of signals coming from different optical sectors. This circuit estimates the ratio of the average optical signal sensed in the photo-detector and the average noise power present...
Proton Microprobe
Santos, Dinis M.; Lopes, J. SousaThis thesis discusxes electronic instrumentation designed and built with a specific application in mind, namely, the application of induced X-ray emission (PIXE) to the qualitative and quantitative analysis materials. The physical principles upon which PIXE is based are briefly reviewed and a short description of the experimental arrangement - particle accelerator and peripheral equipment - where the instrument...
A CMOS signal to noise measurement circuit for wireless applications
Alves, Luís Nero; Aguiar, Rui L.; Santos, Dinis M.This paper describes a circuit able to measure Signal to Noise ratios developed for Infrared (IR) applications. The Signal to Noise ratio is of major importance in IR Sectored Receivers because it provides the basis of selection or combining of signals coming from different optical sectors. This circuit estimates the ratio of the average optical signal sensed in the photo-detector and the average noise power pr...
A CMOS signal to noise measurement circuit for infrared sectored receivers
Alves, Luís Nero; Aguiar, Rui L.; Santos, Dinis M.This paper describes a circuit able to measure Signal to Noise ratios developed for Infrared applications. The Signal to Noise ratio is of major importance in IR Sectored Receivers because it provides the basis of selection or combining of signals coming from different optical sectors. This circuit estimates the ratio of the average optical signal sensed in the photo-detector and the average noise power present...
Delay analysis of a current source CMOS inverter for use in voltage controlled ...
Cura, José L.; Santos, Dinis M.An analysis is performed on the operation of a modified current-source loaded inverter, showing that the proposed modification leads to a more linear characteristic, in terms of delay versus control voltage, than the one obtained with traditional current-starved inverters. A delay cell designed around this inverter is presented. The proposed circuit is intended to be used as a delay of the cell in function of p...