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Bandwidth (signal processing)

About: Bandwidth (signal processing) is a research topic. Over the lifetime, 48550 publications have been published within this topic receiving 600741 citations. The topic is also known as: Bandwidth (signal processing) & bandwidth.


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Patent
03 Oct 2000
TL;DR: In this paper, the harmonics of certain clamped ultrasound transducers are used to generate ultrasound within the liquid of an ultrasonic tank and in a frequency range of between about 100 khz to 350 khz (i.e., "microsonic" frequencies).
Abstract: The invention utilizes harmonics of certain clamped ultrasound transducers to generate ultrasound within the liquid of an ultrasonic tank and in a frequency range of between about 100 khz to 350 khz (i.e., “microsonic” frequencies). The application of microsonic frequencies to liquid preferably occurs simultaneously with a sweeping of the microsonic frequency within the transducer's harmonic bandwidth to reduce or eliminate (a) standing waves within the liquid, (b) other resonances, (c) high energy cavitation implosion, and (d) non-uniform sound fields, each of which is undesirable for cleaning and/or processing of semiconductor wafers and other delicate parts. The invention can also drive ultrasonic transducers such that the frequency of applied energy has a sweep rate within the ultrasonic bandwidth of the transducers; and that sweep rate is also varied so that the sweep rate is substantially non-constant during operation. This reduces or eliminates resonances which are created by transducers operating with a single sweep rate. An ultrasound generator of the invention sometimes utilizes amplitude modulation (AM), and the AM frequency is swept over time so as to reduce resonances. AM control is preferably provided by selecting a portion of the rectified power line frequency. In applications which utilize multiple generators, multiple transducers, and one or more tanks, simultaneously, the invention synchronizes the operation of the generators to a common FM signal to reduce beat frequencies between generators. Each such generator can also be adjusted, through AM, to control the process characteristics within the associated tank. Two or more transducers are sometimes used by the invention, in combination, to broaden the overall bandwidth of acoustical energy applied to the liquid around the primary frequency or one of the harmonics. The bandwidths of the transducers are made to overlap such that an attached generator can drive the transducers, in combination, to deliver ultrasound to the liquid in a broader bandwidth. In a single chamber ultrasound system, two or more generators, each operating or optimized to generate a different range of frequencies, are connected to a multiplexer; and the desired frequency range is selected, and hence the right generator, according to the cavitation implosion energy that is desired within the tank chemistry.

121 citations

Journal ArticleDOI
TL;DR: An organic-based multilayered phased-array antenna package for 28-GHz mm-wave radio access applications is implemented, which incorporates 64 dual-polarized antenna elements and features an air cavity common to all antennas.
Abstract: Silicon-based millimeter-wave (mm-wave) phased-array technologies are enabling directional wireless data communications at Gb/s speeds. In this paper, we review and discuss the challenges of implementing a multichip phased-array antenna module for mm-wave applications using organic buildup substrate technology. A prototype test vehicle has been fabricated and studied to evaluate the antenna and interconnect performance, dielectric properties, package substrate warpage conditions at different temperatures, chip- and board-level joint process reliability, and thermal management feasibility for cooling. Based on the learning from the test vehicle, an organic-based multilayered phased-array antenna package for 28-GHz mm-wave radio access applications is implemented. The package incorporates 64 dual-polarized antenna elements and features an air cavity common to all antennas. Direct probing measurements on a single-antenna element of the package show over 3 GHz of bandwidth and 3-dBi gain at 28 GHz. A phased-array transceiver module has been developed with the package; the module includes four SiGe BiCMOS ICs attached using flip-chip assembly. Module-level measurements in the TX mode show a 35-dB near-ideal output power increase for 64-element power combining; 64-element radiation pattern measurements are reported with a steering range of ± 50° without tapering in off-boresight directions, and 64-element radiation pattern measurements with tapering show achievement of a sidelobe level lower than −20 dB. The transceiver modules achieved 20.64-Gb/s throughput with 256 QAM and 800-MHz bandwidth in direct over-the-air link measurement results.

121 citations

Journal ArticleDOI
TL;DR: In this paper, a 20 GHz bandwidth optoelectronic mixer has been constructed and characterized, and the mixer was then incorporated into a simple superheterodyne receiver architecture, which was shown to have a tangential sensitivity of -66 dBm and a compressive dynamic range of 44 dB.
Abstract: Optoelectronic mixers can exhibit a very wide bandwidth of operation with significantly reduced third-order intermodulation products. A 20 GHz bandwidth optoelectronic mixer has been constructed and characterized. The third-order intermodulation terms were demonstrated to be more than 70 dB below the IF output. The mixer was then incorporated into a simple superheterodyne receiver architecture, which was shown to have a tangential sensitivity of -66 dBm and a compressive dynamic range of 44 dB. System limitations and possible improvements are discussed. >

120 citations

Journal ArticleDOI
TL;DR: It is demonstrated that adiabatic and fast passage ultra-wideband (UWB) pulses can achieve inversion over several hundreds of MHz and thus enhance the measurement sensitivity, as shown by two selected experiments.

120 citations

Patent
27 Jul 1990
TL;DR: In this paper, a receiver processes an NMR signal to produce a baseband image information signal from which two quadrature component signals are derived, and the resultant signal is filtered to remove extraneous signals outside the image information band.
Abstract: A receiver processes an NMR signal to produce a baseband image information signal from which two quadrature component signals are derived. An intermediate frequency section mixes the received NMR signal with two reference signals to shift the image information into a frequency band having a bandwidth BW and centered at a frequency that is 1.5 times the bandwidth BW. The resultant signal is filtered to remove extraneous signals outside the image information band. An analog to digital converter samples the filtered signal at a rate that is twice the bandwidth BW and digitizes the samples into a digital signal. A quadrature detector derives I and Q output signals from the digital signal by alternately selecting digital samples and negating every other sample selected for each of the I and Q output signals. The quadature detector also digitally filters the I and Q signals which are then used to construct an NMR image.

120 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
202217
20211,517
20202,656
20193,121
20183,100
20172,744