نتایج جستجو برای: power spectrum

تعداد نتایج: 688352  

2015
M. Greiner T. A. Enßlin

We investigate whether non-linear effects on the large-scale power spectrum of dark matter, namely the increase in small-scale power and the smearing of baryon acoustic oscillations, can be decreased by a log-transformation or emulated by an exponential transformation of the linear spectrum. To that end we present a formalism to convert the power spectrum of a log-normal field to the power spec...

2004
Shao-Jen Lim John G. Harris

A novel transform space called the ratio spectrum has been developed. The ratio spectrum is formed by plotting the ratio of the power of a low-pass filtered signal to the power of the original unfiltered signal vs. the filter cutoff frequency. The spectrum is necessarily a monotonic function of frequency that is bounded between zero and one. Though we prove that this transform space is mathemat...

2008
RAJIB SAHA TARUN SOURADEEP

The angular power spectrum of Cosmic Microwave Background (CMB) radiation has proved to be an excellent observation to measure different cosmological parameters. In order to extract cosmological parameters precisely we need to remove foreground contamination as well as detector noise bias. In this paper we present a framework to extract CMB angular power spectrum from the multi-frequency observ...

2000
Yun Wang

Model-independent measurements of the primordial power spectrum of matter density fluctuations provide a unique probe of physics in the very early universe, and can provide powerful constraints on inflationary models. We parametrize the primordial power spectrum A2s(k) as an arbitrary function, and measure its binned amplitude from the cosmic microwave background radiation anisotropy (CMB) data...

Journal: :IEICE Transactions 2009
Peng Wang Xiang Chen Shidong Zhou Jing Wang

In spectrum-sharing systems where the secondary user (SU) opportunistically accesses the primary user (PU)’s licensed channel, the SU should satisfy both the transmit power constraint of the SU transmitter and the received power constraint at the PU receiver. This letter studies the ergodic capacity of spectrum-sharing systems in fading channels. The ergodic capacity expression along with the o...

2017
Weifang Sun Bin Yao Yuchao He Binqiang Chen Nianyin Zeng Wangpeng He

Power generation using waste-gas is an effective and green way to reduce the emission of the harmful blast furnace gas (BFG) in pig-iron producing industry. Condition monitoring of mechanical structures in the BFG power plant is of vital importance to guarantee their safety and efficient operations. In this paper, we describe the detection of crack growth of bladed machinery in the BFG power pl...

2015
Fu Chao

Abstract: This paper discusses several methods of power spectrum estimation, respectively using the indirect method and Welch method to estimate power spectrum distribution through the acquisition of vibration signals of circuit breakers, and use the AR hybrid model to estimate different orders of power spectrum estimation. Under different length of data, the order selection method can be deter...

2004
Y P Jing

Because of mass assignment onto grid points in the measurement of the power spectrum using the Fast Fourier Transform (FFT), the raw power spectrum |δ f (k)| 2 estimated with FFT is not the same as the true power spectrum P (k). In this paper, we derive the formula which relates |δ

1999
Mark D. Skowronski John G. Harris

tic signal. The discrete-time ratio spectrum of X ( k ) is Recently, Lam and Harris have developed a novel specN-I tral representation called the ratio spectrum [l]. The I K r " ( k ) 1 2 (1) Output Power k=O N-1 ratio spectrum is formed by taking the ratio of the power of a low-pass filtered signal to the power of the original unfiltered signal for all filter cutoff frequencies. FeaX(m) = Inpu...

2004
Y P Jing

Because of mass assignment onto grid points in the measurement of the power spectrum using the Fast Fourier Transform (FFT), the raw power spectrum |δ f (k)| 2 estimated with FFT is not the same as the true power spectrum P (k). In this paper, we derive the formula which relates |δ

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