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Radio frequency

About: Radio frequency is a(n) research topic. Over the lifetime, 44413 publication(s) have been published within this topic receiving 448181 citation(s). The topic is also known as: RF & radio frequency. more


Journal ArticleDOI: 10.1109/26.843135
Moe Z. Win1, Robert A. Scholtz2Institutions (2)
Abstract: Attractive features of time-hopping spread-spectrum multiple-access systems employing impulse signal technology are outlined, and emerging design issues are described. Performance of such communications systems in terms of achievable transmission rate and multiple-access capability are estimated for both analog and digital data modulation formats under ideal multiple-access channel conditions. more

Topics: Spread spectrum (58%), Communications system (57%), Modulation (55%) more

2,659 Citations

Book ChapterDOI: 10.1007/978-1-4615-1963-8_40
E. M. Purcell1Institutions (1)
01 Jan 1995-Physical Review D
Topics: Radio frequency (61%), Spontaneous emission (54%)

2,054 Citations

Journal ArticleDOI: 10.1002/J.1538-7305.1968.TB00069.X
Abstract: The statistical characteristics of the fields and signals in the reception of radio frequencies by a moving vehicle are deduced from a scattering propagation model. The model assumes that the field incident on the receiver antenna is composed of randomly phased azimuthal plane waves of arbitrary azimuth angles. Amplitude and phase distributions and spatial correlations of fields and signals are deduced, and a simple direct relationship is established between the signal amplitude spectrum and the product of the incident plane waves' angular distribution and the azimuthal antenna gain. The coherence of two mobile-radio signals of different frequencies is shown to depend on the statistical distribution of the relative time delays in the arrival of the component waves, and the coherent bandwidth is shown to be the inverse of the spread in time delays. Wherever possible theoretical predictions are compared with the experimental results. There is sufficient agreement to indicate the validity of the approach. Agreement improves if allowance is made for the nonstationary character of mobile-radio signals. more

Topics: Plane wave (54%), Azimuth (54%), Radio frequency (53%) more

2,042 Citations

Journal ArticleDOI: 10.1109/22.989965
Abstract: The generation of RF/microwave power is required not only in wireless communications, but also in applications such as jamming, imaging, RF heating, and miniature dc/dc converters. Each application has its own unique requirements for frequency, bandwidth, load, power, efficiency, linearity, and cost. RF power is generated by a wide variety of techniques, implementations, and active devices. Power amplifiers are incorporated into transmitters in a similarly wide variety of architectures, including linear, Kalm, envelope tracking, outphasing, and Doherty. Linearity can be improved through techniques such as feedback, feedforward, and predistortion. more

Topics: RF power amplifier (65%), Amplifier (59%), Predistortion (59%) more

1,277 Citations

Journal ArticleDOI: 10.1103/PHYSREVLETT.85.2264
Ronald Holzwarth1, Th. Udem1, Theodor W. Hänsch1, Jonathan Knight2  +2 moreInstitutions (2)
Abstract: We have used the frequency comb generated by a femtosecond mode-locked laser and broadened to more than an optical octave in a photonic crystal fiber to realize a frequency chain that links a 10 MHz radio frequency reference phase-coherently in one step to the optical region. By comparison with a similar frequency chain we set an upper limit for the uncertainty of this new approach to 5. 1x10(-16). This opens the door for measurement and synthesis of virtually any optical frequency and is ready to revolutionize frequency metrology. more

Topics: Frequency synthesizer (65%), Frequency multiplier (63%), Frequency comb (62%) more

1,073 Citations

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Topic's top 5 most impactful authors

Ahmadreza Rofougaran

66 papers, 1.2K citations

Arnan Mitchell

56 papers, 1.3K citations

David J. Moss

36 papers, 916 citations

Roberto Morandotti

28 papers, 629 citations

Kun Xu

28 papers, 266 citations

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