The effectiveness of an optical-fiber-mounted electro-optic probe as a scanning electric-fieldmapping tool is demonstrated in diagnostic measurements on microwave and millimeter-wave circuits, antennas, and arrays. A combined electric-field and thermal-imaging capability will also be discussed.The interaction of optical beams and electrical signals in an electro-optic medium provides a fundamental and convenient means for introducing microwave or digital data into an optical transmission channel. This is accomplished through the well-known process of electro-optic modulation. Similarly, the characteristics of an electrical waveform can also be determined using an optical beam when this beam is coincident with, and intensity modulated by, the part of the unknown electrical signal that enters an appropriately oriented electro-optic medium. When a mode-locked laser having a pulse duration much shorter then an electrical feature to be measured is used to interrogate one small part of a repetitive waveform (over an interval At), then the assembly of many "At" constituents from different parts of the waveform into a representation of the original signal is known as electro-optic sampling [1,2]. Dozens of examples of time-domain electro-optic-sampling measurements have appeared in the literature over the past 20 years. They highlight the applications of the technique in high-bandwidth-photodetector characterization [3], discrete-device analysis [4], the extraction of clock and large-signal waveforms from within digital and nonlinear circuits [5], the measurement of pulsed, terahertz signals [6], and other areas. In the diagnostic testing of linear microwave systems or components, another embodiment of electro-optic sampling in which the amplitude and phase of a single frequency are measured at a variety of spatial locations has also been developed [7]. These measurements of spatial field distributions have increased in popularity for the characterization of both active [8] and passive [9] circuits, where the microwave signals are either guided [IO] or radiating [I I]. They can be made using either an electro-optic substrate [I21 or an electro-optic medium externally inserted into a fringing or radiated electric field [13].In this paper, we will discuss the most highly evolved electric-field mapping system that, to our knowledge, has been developed to date. It is a system that: separately distinguishes three orthogonal vector components of the electric field; senses both amplitude and phase; is flexibly positioned due to optical-fiber coupling of its probe; has single-micrometer spatial resolution; has greater than 100-GHz bandwidth; and has a low invasiveness even with its probe positioned in the near field of a device under test (DUT). Furthermore, the system can be modified so that information contained in part of the optical beam is also analyzed to reveal the temperature at the probe location. At the same time the probe is scanned to map out the electric field, it can thus also construct a thermal image. Figure I il...
The central purpose of this research was to determine the nature of musically untrained adults’ verbal response to repeated hearings of music excerpts when asked questions that encouraged interpretive responses. Two specific research questions served as the basis for the investigation: What categories emerge from an analysis of verbal responses? How does the musical understanding represented by verbal responses compare to extant literature on the music listening of adult nonmusicians? Twelve adult nonmusicians ranging in age from 28 to 77 were interviewed individually after they had listened twice to six musical excerpts, followed by a repetition of the procedure after a one-week interval. A content analysis of their responses employed a grounded theory approach to generate a list of categories. Results indicate that participants responded across a range of musical, extramusical, affective, and preference categories, and that repeated hearings of selected pieces resulted in more detailed responses for several participants.
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.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.