Topic
Fundamental frequency
About: Fundamental frequency is a research topic. Over the lifetime, 8941 publications have been published within this topic receiving 131583 citations.
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Papers
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18 Jun 1990
TL;DR: In this article, the influence of harmonics on the steady state behavior of relays was evaluated using fundamental currents and/or voltages, and single-frequency inputs that were multiples of the fundamental frequency.
Abstract: The authors attempt to show, theoretically and by laboratory tests, the influence of harmonics on protective relays. Representative relays using various operating principles were tested using fundamental currents and/or voltages. They were then tested using single-frequency inputs that were multiples of the fundamental frequency. Finally, tests were made using realistic combinations of fundamental and harmonics. From the theoretical concepts and expectations discussed and the series of tests performed, it is evident that the influence of mixed frequency harmonics (with magnitude decreasing with order) on the steady state behavior of the protective relays studied is minor and insignificant. The influence of pure single-frequency inputs, above the fundamental, on various protective relays was also evaluated. Results showed a distinct change in relay operation. >
38 citations
Patent•
28 Aug 2000TL;DR: In this article, a signal under measurement is converted into a digital signal by an AD converter, and a band-pass filtering process is applied to the digital signal to take out only components around a fundamental frequency.
Abstract: A signal under measurement is converted into a digital signal by an AD converter, and a band-pass filtering process is applied to the digital signal to take out only components around a fundamental frequency of the signal under measurement. A data around a zero-crossing of the components around the fundamental frequency is interpolated to estimate a timing close to a zero-crossing point. A difference between adjacent timings in the estimated zero-crossing timing sequence is calculated to obtain an instantaneous period data sequence. A period jitter is obtained from the instantaneous period data sequence.
38 citations
TL;DR: In this article, the feasibility studies concerning an accurate voltage phasor measurement in a series-compensated network undergoing large disturbances are described, and the principal modes of distortions in such a network are described.
Abstract: This paper describes the feasibility studies concerning an accurate voltage phasor measurement in a series-compensated network undergoing large disturbances. The principal modes of distortions in such a network are described. Some of these modes are changing with the fundamental frequency. The phasor evaluation is based on a new digital filter approach in which the fundamental frequency is estimated using a least-square algorithm. The need to have special potential (voltage) transformers is also discussed. This approach would be used in a shunt reactor switching scheme for an overall voltage control of a transmission network. >
38 citations
TL;DR: A novel modulation scheme in which the ratio of the fundamental modulation frequency to the cavity fundamental frequency is rational (nonintegral) is used, which should be applicable to lasers and to soliton transmission.
Abstract: 50-Gbit/s, 3.8-kbit packets of optical return-to-zero data have been stored in a unidirectional fiber storage ring by use of a novel modulation scheme in which the ratio of the fundamental modulation frequency to the cavity fundamental frequency is rational (nonintegral). The modulation technique should be applicable to lasers and to soliton transmission.
38 citations
TL;DR: This work proposes an alternative approach that exploits the dynamics between the fundamental frequency and speech energy to capture prosodic differences and shows that the prosodic features provide complementary information to conventional systems by fusing the prosody systems with the state-of-the-art system.
38 citations