Results of 1.8-GHz narrow band measurements in an urban area to characterize the coherence bandwidth at 0.9 and 0.5 correlation level are presented. The correlation coefficient between two frequency-spaced envelopes is found to be highly dependent on the receiver position. The confidence interval of the correlation coefficient estimator is calculated to ensure accuracy. For coherence bandwidth, frequency separations less than 60 kHz and 136 kHz will guarantee correlation levels larger than 0.9 and 0.5, respectively, for 90% of the time.
A characterization technique, including a mathematical model involving extensive computational resources, is introduced to study the behavior of an electro-optical space switch based on semiconductor optical amplifier (SOA). The model encompasses the precise emulation of device nonlinearities and its transient performance, allowing the characterization of its transient response. The calibration process includes the evaluation of parasites from the SOA connection, mounting and encapsulation, and parameter extraction of the active cavity. The numerical results are compared to experimental data for various operational conditions, with close similarities. The characterization technique can be adapted for other electro-optical devices, such as directedmodulated lasers, amplitude modulators and electro-optical switches.
Time selective fading investigations based on 3.5-GHz SISO narrowband envelope data are carried out in a microcellular propagation environment. Spatial correlation functions are calculated and compared to the theoretical Nakagami-Rice correlation function, and a good match was obtained. An alternative formulation of the autocorrelation estimator suitable not only for stationary environments is used in this article. Based on the field trial data, coherence time (To) statistics at 0.5-correlation level were calculated and found to be highly dependent on the receiver position. To distribution functions at 0.5-correlation level showed that the coherence time stays above 1.7 ms for 90% of time when the receiver is moving at 30 km/h.
Microwave pulse bursts were obtained through optical domain intensity modulated microwave carriers, sliced by cascaded modulator technique, followed by non-linear semiconductor optical amplifier (SOA) pre-chirp. After 3 to 18 km of buried fiber propagation and photo detection, the microwave signals presented increased extinction ratio, up to 36 GHz, with pulse modulation windows from 166 to 1000 picoseconds, achieving rise times near to 10 ps.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.