Laleh Najafizadeh

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The ability to assess frontal lobe function in a rapid, objective, and standardized way, without the need for expertise in cognitive test administration might be particularly helpful in mild traumatic brain injury (TBI), where objective measures are needed. Functional near infrared spectroscopy (fNIRS) is a reliable technique to noninvasively measure local(More)
—Imperfect channel estimation (ICE) can severely degrade the bit error rate (BER) of digital modulations with maximum ratio combining (MRC) diversity reception. The resulting performance analysis problem in its most general setting has not been addressed before. In this paper, the effect of ICE on the BER of an arbitrary square/rectangular Gray-coded(More)
A new approach to trace the dynamic patterns of task-based functional connectivity, by combining signal segmentation, dynamic time warping (DTW), and Quality Threshold (QT) clustering techniques, is presented. Electroencephalography (EEG) signals of 5 healthy subjects were recorded as they performed an auditory oddball and a visual modified oddball tasks.(More)
When a diode-connected MOS transistor is biased with a PTAT current source, the gate-source voltage of such transistor can be temperature independent. Based on this idea a circuit is designed and implemented in a standard 0.18-µm CMOS technology. The simulations show that the output voltage of this reference has the temperature coefficient of 4 ppm/ • C in(More)
— In this paper, we derive a general expression for the bit error rate (BER) performance of an arbitrary square/rectangular Gray-coded quadratic amplitude modulation (QAM) scheme. This general formula requires a number of conditional probabilities which we derive in closed-form for independent and nonidentically distributed (i.n.d.) Rayleigh fading(More)
— We present the first investigation of the optimal implementation of SiGe BiCMOS precision voltage references for extreme temperature range applications (+120 o C to-180 o C and below). We have developed and fabricated two unique Ge profiles optimized specifically for cryogenic operation, and for the first time compare the impact of Ge profile shape on(More)
—A comprehensive investigation of the effects of proton irradiation on the performance of SiGe BiCMOS precision voltage references intended for extreme environment operational conditions is presented. The voltage reference circuits were designed in two distinct SiGe BiCMOS technology platforms (first generation (50 GHz) and third generation (200 GHz)) in(More)
A systematic design methodology utilizing piecewise curvature correction technique for the purpose of improving the temperature coefficient of bandgap references (BGRs) is presented in this paper. It is shown that the temperature dependency of the drain current of a MOSFET transistor depends on the transistor's operating region. Using this property, a(More)