We extensively investigated the effects of the temperature on the DC behaviour, the small signal and the noise performance at microwave frequencies of pseudomorphic HEMTs. The measured data were then employed to extract temperature dependent models by means of several extraction techniques. The relevant experimental data show that the most important electrical parameters, such as the output cur...

Continuous wave direct-conversion microwave Doppler radar can be used to detect cardiopulmonary activity at a distance. Demodulation sensitivity to a target’s distance in a single channel system can be solved by using a quadrature direct-conversion receiver. A particular challenge in this technique is accurate demodulation in the presence of unwanted dc offset. A center tracking compensation me...

in this paper, we investigate the parameters affecting total harmonic distortion (thd) and power supply rejection ratio (psrr) in pwm class d amplifiers (cdas) on the basis of linear models with feedback. from our mathematical analysis, we show that the thd of a pwm class d amplifier with feedback can be improved by increasing the gain of the integrator through adding another amplifier at the o...

BACKGROUND In Impedance Microbiology, the time during which the measuring equipment is connected to the bipolar cells is rather long, usually between 6 to 24 hrs for microorganisms with duplication times in the order of less than one hour and concentrations ranging from 10(1) to 10(7) [CFU/ml]. Under these conditions, the electrode-electrolyte interface impedance may show a slow drift of about ...

Transverse electromagnetic (TEM) cell is a well-known method for the qualification of radiated emission from integrated circuits (ICs). Combined with 180° hybrid coupler, it provides simple quantifying (RE). However, typical transformer or coupled line based couplers have limited bandwidth which cannot cover full frequency range required by IC tests (150 kHz to 1 GHz). This article presents des...

The power requirements imposed on the amplifier by piezoelectric actuators is discussed. We consider a two-degree-of-freedom mechanical system driven by a piezoelectric stack for the purpose of analyzing power flow and power dissipation of four amplifiers. Two of the amplifiers are benchtop linear amplifiers. The other two amplifiers are based on switching topologies. The power consumption of a...

The precise control of direct current (dc) magnetic fields is crucial in a wide range experimental platforms, from ultracold quantum gases and nuclear resonance to precision measurements. In each these cases, the Zeeman effect causes states shift energy as function field. development low-noise sources essential because electromagnets are preferred tool dynamically Here, we describe an ultra-low...

The neuroelectric activity of the brain provides a variety of instances of rhythmic events. The periodicity of such events ranges from milliseconds in the case of the firing of individual neurons t o circadian in the case of certain aspects of the "sleep" EEG. This paper will (be devoted t o a discussion of (i) methodological approaches to the detection and description of s6me of the shorter pe...