22,314 research outputs found
AM/AM and AM/PM power amplifier characterisation technique
No full textA novel power amplifier's AM/AM and AM/PM characterisation technique is proposed, making use of two-tone test miming a DSB-SC modulated signal. Its main advantage is related to the possibility to extract the amplifier behaviour under operating conditions closer to actual modulated signals. Moreover, the proposed set-up is featured by simplicity, reduced cost and characterisation effort
Low cost AM/AM and AM/PM characterization setup based on scalar measurements
No full textThis paper presents a fast and low cost AM/AM and AM/PM characterization technique. A simple and functional measurement setup based only on scalar power measurements allows both magnitude and phase single carrier characterization of the device under test (DUT). The proposed solution to evaluate nonlinear distortion of the DUT avoids the use of expensive systems, like vector network analyzer (VNA) and its calibration methods. To be implemented, the setup requires a RF source, four power sensors, a Wilkinson power splitter and a quadrature hybrid coupler. The proposed technique has been validated measuring a commercial PA at 3 GHz and comparing the results with the ones obtained by using a VNA. A very good agreement has been obtained
EMDR therapy for PTSD after motor vehicle accidents: meta-analytic evidence for specific treatment
No full textMotor vehicle accident (MVA) victims may suffer both acute and post-traumatic stress disorders (PTSD). With PTSD affecting social, interpersonal and occupational functioning, clinicians as well as the National Institute of Health are very interested in identifying the most effective psychological treatment to reduce PTSD. From research findings, eye movement desensitization and reprocessing (EMDR) therapy is considered as one of the effective treatment of PTSD. In this paper, we present the results of a meta-analysis of fMRI studies on PTSD after MVA through activation likelihood estimation. We found that PTSD following MVA is characterized by neural modifications in the anterior cingulate cortex (ACC), a cerebral structure involved in fear-conditioning mechanisms. Basing on previous findings in both humans and animals, which demonstrate that desensitization techniques and extinction protocols act on the limbic system, the effectiveness of EMDR and of cognitive behavioral therapies (CBT) may be related to the fact that during these therapies the ACC is stimulated by desensitization
Positive effects of blue light on executive functions: future implications for air traffic controllers.
No full textInvestigation of the AM/PM distortion in Doherty power amplifiers
No full textIn this paper, a theoretical investigation of the causes of the AM/PM distortion in Doherty Power Amplifiers is presented for the first time. The distortion sources are identified and a solution to mitigate the AM/PM conversion through the input termination of the Carrier amplifier is also highlighted. The relevant analysis is carried out using a simplified model of the active device and validated by means of full nonlinear model of a commercial GaN HEMT transistor. The role of the Miller effect in such a kind of distortion is stressed, demonstrating the existing link between output load modulation and phase distortion
El spinozismo de Humberto Giannini. La reflexividad como la construcción política de la resistencia
No full textEste artículo busca situar el trabajo filosófico de Humberto Giannini en la investigación en torno al pensamiento de Baruch de Spinoza en Suramérica. En el primer apartado se hará una breve reseña del estado de los estudio sobre Spinoza en América del Sur, situando a Giannini en dicho espectro. En segundo lugar, se expondrá como la filosofía de Spinoza tiene una presencia discontinua, pero permanente en su reflexión. Luego, se propondrá, a partir de las conclusiones de los apartados anteriores una interpretación de la lectura que hace Giannini de Spinoza, enfatizando en la confrontación crítica que realiza frente a la hegemonía del orden dictatorial en Chile
Protecting Animals 36: Author Witi Ihimaera
No full textIn this very special episode of Knowing Animals I am joined by beloved New Zealand author Witi Ihimaera. Witi has written many books featuring nonhuman animals. He offers us a non-colonial lens through which to think about the human/nonhuman relationship
High efficiency and low distortion GaN MMIC power amplifier for 7 Ghz applications
No full textThe guidelines for designing a high efficiency and low distortion 2-stages Gallium Nitride (GaN) power amplifier (PA) are presented. In particular, the developed approach to mitigate the phase distortion (AM/PM) without worsening the efficiency and gain features is adopted to design a 7GHz PA based on 0.25 umm GaN process from TriQuint. When tested with continuous wave signals the PA shows a saturated output power higher than 37 dBm, with an efficiency larger than 60% and an AM/AM and AM/PM distortions lower than 2 dB and +/-1 deg, respectively. The MMIC chip size is 3x3mm2
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