scispace - formally typeset
Search or ask a question
Topic

Sine wave

About: Sine wave is a research topic. Over the lifetime, 12183 publications have been published within this topic receiving 93013 citations. The topic is also known as: sinusoid.


Papers
More filters
Journal ArticleDOI
TL;DR: In this paper, it was shown that linear growth and mixing of Langmuir modes provides a more natural explanation of modulated LangmuIR waves than do wave-wave processes previously proposed, at least for cusp waves encountered by TRICE.
Abstract: [1] HF wave receivers on the Twin Rockets to Investigate Cusp Electrodynamics (TRICE) detect numerous 20–250 ms duration Langmuir wave bursts. Investigation of 41 bursts at 967–984 km, where the gyrofrequency exceeds the plasma frequency, reveals a characteristic signature whereby the Langmuir wave bandwidth and highest frequency maximize at the center of the bursts, suggesting that bursts coincide with density enhancements. The Langmuir waveforms are modulated at frequencies up to 50 kHz, with significant modulation at frequencies <1 kHz about 10% of the time. Where amplitudes of the modulated waves pass through zero, the phase of the carrier wave shifts by 180°, consistent with a superposition of interfering waves. The corresponding wave spectrum has multiple <1 kHz bandwidth peaks separated by <1–50 kHz. For no averaging, the wave E field statistics, dominated by the carrier Langmuir wave, show an E+1 dependence at small E fields as expected for rectified sine waves. For moderate averaging, the statistics, dominated by the envelope field, show a spectral index of ≈ +2 at small E fields, consistent with numerical simulations of independent stochastically driven waves. The wave statistics, absence of VLF waves, lack of transition in the modulation occurrence as a function of frequency, and tendency of the spread spectrum to cut off at the ambient plasma frequency outside the density enhancement associated with the wave burst suggest that linear growth and mixing of Langmuir modes provides a more natural explanation of modulated Langmuir waves than do wave-wave processes previously proposed, at least for cusp waves encountered by TRICE.

19 citations

01 Feb 2011
TL;DR: In this article, a feedback control mechanism is added to an echo state network (ESN) pattern generator in order to modulate its output patterns with the purpose of tracking slowly varying control targets, e.g. shift, amplitude, or frequency of an oscillatory pattern.
Abstract: In this report we present a method of adding a feedback control mechanism to an echo state network (ESN) pattern generator in order to modulate its output patterns with the purpose of tracking slowly varying control targets, e.g. shift, amplitude, or frequency of an oscillatory pattern. A proofof- principle case study is presented where a basic ESN is trained to produce a stable sinewave oscillation with fixed shift, amplitude and frequency. With the controller in place, the system demonstrates that the shift, amplitude and frequency of the produced sine waveform can be modulated simultaneously by suitably generated slow varying control signals inserted into the network. Furthermore, an equilibration procedure is introduced to relearn ESN weights such that the equilibrated ESN pattern generator can approximately reproduce the reservoir dynamics across the controllable range, with the feedback control loop switched off. As a result, when reconnecting the feedback control loop to the equilibrated ESN, the energy of the control signals are many orders of magnitude smaller compared to the native system.

19 citations

Patent
04 Sep 1986
TL;DR: In this paper, the first and second signals are used to modulate the amplitude of two sinusoidal waves at a subcarrier frequency and in phase quadrature, so as to synthesize the chrominance portion of a composite video signal.
Abstract: A visual indication of the relationship between first and second electrical signals, such as the left and right channel signals in a stereophonic audio system, is provided through use of a video vectorscope. The first and second signals are used to modulate the amplitude of two sinusoidal waves at a subcarrier frequency and in phase quadrature, so as to synthesize the chrominance portion of a composite video signal. The two modulated sine waves are additively combined, and the resulting signal is applied to the input terminal of the vectorscope.

19 citations

Patent
Kiyoshi Shibuya1, Hitoshi Shirai1
19 Jun 1981
TL;DR: In this article, a frequency shift keying system is proposed, where sine waves of different frequencies f0 and f1 are selectively provided as a modulated output signal in accordance with the level of an input code.
Abstract: In a frequency shift keying system, sine waves of different frequencies f0 and f1 are selectively provided as a modulated output signal in accordance with the level of an input code. One of two pulse signals having frequencies N times higher than the frequencies f0 and f1 is selected by a selector in accordance with the level of the input code, and the selector output pulse signal is frequency divided by a counter down to 1/N to obtain a pulse signal having a duty ratio of 50% and a frequency of f0 or f1. The pulse signal obtained is converted by a low-pass filter into a sine wave. The modulated output signal has no phase shift even at the point of transition of the input code level and has continuity and hence has little modulation distortion.

19 citations

Patent
02 Mar 2007
TL;DR: In this paper, a DC bias voltage 2 lower than the breakdown voltage is applied to an InGaAs/InP avalanche photodiode (APD) to detect a single photon in the 1550nm communication band at a high speed.
Abstract: In order to operate a single photon detector in communication wavelength band at a high speed, a DC bias voltage 2 lower than the breakdown voltage is applied to an InGaAs/InP avalanche photodiode (APD) 1. A 500MHz sine wave gating signal 3 is superimposed with the DC bias voltage 2 and applied to the APD 1 so as to exceed the breakdown voltage by about 4V in a fractional time of each period. The sine wave gating signal 3 passed through the APD 1 is substantially completely removed by a filter 4, thereby improving S/N and enabling to detect a single photon even if the avalanche multiplication time is shortened to reduce the after pulse and the detection period. As a result, it achieves to detect a single photon in the 1550nm communication band at a high speed.

19 citations


Network Information
Related Topics (5)
Voltage
296.3K papers, 1.7M citations
79% related
Signal
674.2K papers, 4.5M citations
78% related
Artificial neural network
207K papers, 4.5M citations
77% related
Control theory
299.6K papers, 3.1M citations
77% related
Robustness (computer science)
94.7K papers, 1.6M citations
77% related
Performance
Metrics
No. of papers in the topic in previous years
YearPapers
202378
2022157
2021138
2020253
2019344
2018336