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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.


Papers
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Journal ArticleDOI
TL;DR: To the best of the knowledge, this actuator has achieved the largest servo bandwidth for a piezoelectric transducer (PZT).
Abstract: We present a high bandwidth piezoelectric-actuated mirror for length stabilization of an optical cavity. The actuator displays a transfer function with a flat amplitude response and greater than 135 masculine phase margin up to 200 kHz, allowing a 180 kHz unity gain frequency to be achieved in a closed servo loop. To the best of our knowledge, this actuator has achieved the largest servo bandwidth for a piezoelectric transducer (PZT). The actuator should be very useful in a wide variety of applications requiring precision control of optical lengths, including laser frequency stabilization, optical interferometers, and optical communications.

137 citations

Journal ArticleDOI
TL;DR: A novel self-decoupled multiple-input multiple-output (MIMO) antenna pair with a shared radiator with promising potential for the future highly integrated MIMO antennas for 5G smartphones is proposed.
Abstract: In this article, a novel self-decoupled multiple-input multiple-output (MIMO) antenna pair with a shared radiator is proposed for fifth-generation (5G) smartphones. In our approach, a radiator is directly excited by two feeding ports, and interestingly, the two ports are naturally isolated across a wide bandwidth without using any extra decoupling structures. To offer a deep physical insight of the self-decoupling mechanism, a mode-cancellation method based on the synthesis of common and differential modes is developed for the first time. The proposed self-decoupled antenna pair shows a good isolation of better than 11.5 dB across the 5G N77 band (3.3–4.2 GHz) with a radiation pattern diversity property. Based on the self-decoupled antenna pair, an $8 \times 8$ MIMO antenna system, constituted by four sets of antenna pairs, is simulated, fabricated, and measured to validate the concept. The experimental results demonstrate that the proposed $8 \times 8$ MIMO system can offer an isolation of better than 10.5 dB between all ports and a high total efficiency of 63.1%–85.1% across 3.3–4.2 GHz. With the advantages of self-decoupling, shared radiator, simple structure, wide bandwidth, and high efficiency, the proposed design scheme exhibits promising potential for the future highly integrated MIMO antennas for 5G smartphones.

137 citations

Journal ArticleDOI
Rolf Landauer1
28 Jun 1996-Science
TL;DR: Alternative communication methods are proposed to show that there is no unavoidable minimal energy requirement per transmitted bit.
Abstract: The literature describing the energy needs for a communications channel has been dominated by analyses of linear electromagnetic transmission, often without awareness that this is a special case. This case leads to the conclusion that an amount of energy equal to kTln 2, where kT is the thermal noise per unit bandwidth, is needed to transmit a bit, and more if quantized channels are used with photon energies hnu > kT. Alternative communication methods are proposed to show that there is no unavoidable minimal energy requirement per transmitted bit. These methods are invoked as part of an analysis of ultimate limits and not as practical procedures.

137 citations

Journal ArticleDOI
L.J. Ippolito1
01 Feb 1981
TL;DR: In this article, the authors present a review of the most recent information on the effects of the earth's atmosphere on space communications systems and the impact of various propagation factors on communications system design criteria.
Abstract: This paper presents a review of the most recent information on the effects of the earth's atmosphere on space communications systems. The design and reliable operation of satellite systems which provide the many applications in space and rely on the transmission of radio waves for communications and scientific purposes are dependent on the propagation characteristics of the transmission path. The presence of atmospheric gases, clouds, fog, precipitation, and turbulence cause uncontrolled variations in the signal characteristics which can result in a reduction of the quality and reliability of the transmitted information. Models and techniques used in the prediction of atmospheric effects as influenced by frequency, geography, elevation angle, and type of transmission are discussed. Recent data on performance characteristics obtained from direct measurements on satellite links operating to above 30 GHz are reviewed. Particular emphasis is placed on the effects of precipitation on the earth-space path, including rain attenuation, and rain and ice-particle depolarization. Sky noise, antenna gain degradation, scintillations, and bandwidth coherence are also discussed. The impact of the various propagation factors on communications system design criteria is presented. These criteria include link reliability, power margins, noise contributions, modulation and polarization factors, channel crosstalk, error-rate, and bandwidth limitations.

137 citations

Proceedings ArticleDOI
Yiran Ma1, Qi Yang1, Yan Tang1, Simin Chen1, William Shieh1 
22 Mar 2009
TL;DR: In this article, a 1.1-Tb/s per channel coherent optical OFDM transmission over 600-km SSMF fiber is demonstrated assisted with a recirculating frequency shifter.
Abstract: 1-Tb/s per channel coherent optical OFDM transmission over 600-km SSMF fiber is demonstrated assisted with a recirculating frequency shifter. Record spectral efficiency and transmission reach is achieved at 1-Tb/s channel rate without Raman amplification.

137 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