Function Of Input Signal Frequency Research Articles

Microwave photonics instantaneous frequency measurement receiver based on a Sagnac loop.

A microwave photonics instantaneous frequency measurement receiver was conceived and practically demonstrated. The system is based on phase modulation inside a Sagnac loop and therefore needs no bias voltage, resulting in no DC bias drifts. The system provides a DC output whose amplitude is a function of input signal frequency, and thus no high-frequency photo-detector is required. Furthermore, the system exhibits a very good sensitivity without the aid of any sort of electrical noise cancellation techniques, such as lock-in amplification. This makes the system response faster, which would be another benefit for electronic warfare applications. Less than 6% measurement error was achieved over a 0.01-40GHz frequency range for -30 dBm RF level. Also, a 10% error was achieved at -51 dBm RF power level.

A Frequency Model of a Continuously Driven Clocked CMOS Comparator

A frequency model of a continuously driven clocked CMOS comparator with the effect of the input signal during regeneration is presented. The model utilizes a small-signal linear model derived from the theoretical analysis of the comparison error caused by the transition from the tracking mode to the regeneration mode. The comparison error voltage is a function of input signal frequency and is represented with the transfer function. The correctness of the model is assured by several transistor-level simulation results. The model provides a valuable insight for the design of high-speed comparators.

Capacitance Simulations and Measurements of 3D Pixel Sensors Under 55 MeV Proton Exposure

3D pixel sensors are a novel type of silicon detector designed for high energy physics and other applications. Their features include high spatial resolution and radiation tolerance. The design consists of alternating rows of n- and p-type columns in a p-type substrate. Capacitance data are presented for 3D pixel devices characterized after exposure to various fluences of 55 MeV protons. Simulations and two methods for the measurement of the inter-electrode capacitance as a function of input signal frequency are shown.

Stochastic giant resonance

The model of an electric circuit with dichotomous resistance is investigated. It is shown that the dichotomous resistance can induce a phenomenon of stochastic giant resonance for the signal-to-noise ratio (SNR) as a function of input signal frequency. This phenomenon is a direct consequence of the existence of a zero noise power spectrum, with a nonzero signal power spectrum for the same parameters. In addition, two kinds of the usual stochastic resonance phenomena have been obtained for the SNR. One is as a function of the correlation time of the asymmetric dichotomous resistance; the other is as a function of the input signal frequency.

Device modeling of ferroelectric capacitors

A physically based methodology is developed for modeling the behavior of electrical circuits containing nonideal ferroelectric capacitors. The methodology is illustrated by modeling the discrete ferroelectric capacitor as a stacked dielectric structure, with switching ferroelectric and nonswitching dielectric layers. Electrical properties of a modified Sawyer–Tower circuit are predicted by the model. Distortions of hysteresis loops due to resistive losses as a function of input signal frequency are accurately predicted by the model. The effect of signal amplitude variations predicted by the model also agree with experimental data. The model is used as a diagnostic tool to demonstrate that cycling degradation, at least for the sample investigated, cannot be modeled by the formation of nonswitching dielectric layer(s) or the formation of conductive regions near the electrodes, but is consistent with a spatially uniform reduction in the number of switching dipoles.