Encontrados 5 documentos, a visualizar página 1 de 1
Bandwidth aspects in second generation current conveyors
Alves, L. N.; Aguiar, R.L.; Santos, D.M.This paper discusses bandwidth problems associated with second-generation current conveyors (CCII). In particular, our work is centered in high-capacitance applications, and has been oriented for wireless optical links and applied physics. We discuss techniques for improving bandwidth in these CCIIs, and develop a new CCII structure with larger bandwidth than traditional circuits. These circuits are then compar...
A low-noise CMOS front-end for TOF-PET
Rolo, M. D.; Alves, L. N.; Martins, E. V.; Rivetti, A.; Santos, M. B.; Varela, J.An analogue CMOS front-end for triggering and amplification of signals produced by a silicon photomultiplier (SiPM) coupled to a LYSO scintillator is proposed. The solution is intended for time-of-flight measurement in compact Positron Emission Tomography (TOF-PET) medical imaging equipments where excellent timing resolution is required (approximate to 100 ps). A CMOS 0.13 mu m technology was used to implement ...
General model for delayed feedback and its application to transimpedance amplif...
Alves, L. N.; Barbosa, L.; Macedo, E.A.L.; Aguiar, R.L.Delays in real systems can be of two types: i) intrinsic delays - due to the physical principles of operation of each electronic device; ii) designed delays - due to extra circuits used to add the desired delay. Previous work established the possibility of achieving bandwidth improvements using small delays inside the feedback loop of feedback amplifiers. The modeling approach followed on these contributions us...
On the effect of time delays in negative feedback amplifiers
Alves, L. N.; Aguiar, R.L.Time delays are intrinsic to all existing devices and circuits. For the majority of applications, time delays are so small that their effects can be disregarded. However, when considering feedback amplifiers, depending on open-loop poles and loop gain, the effect of a small time delay inside the feedback path may turn to be of considerable importance. This paper analyzes the frequency response effects associate...
A sectored receiver for infrared wireless networks
Alves, L. N.; Aguiar, Rui L.; Vasconcelos, Eduardo de; Cura, Jose LuisThis paper presents an experimental sectored receiver for infrared wireless networks. The receiver comprises two sectors, each with a switched gain front-end and a signal-to-noise ratio estimator. These are then interconnected with a best-sector selector unit, able to compensate the gain switching characteristics of the front-ends. The circuit has been designed in a 0.8 μm CMOS technology.
| Financiadores do RCAAP | |||||||
|
|
|
|
|
|
||