# What is Spectral analysis: Definition and 31 Discussions

Least-squares spectral analysis (LSSA) is a method of estimating a frequency spectrum, based on a least squares fit of sinusoids to data samples, similar to Fourier analysis. Fourier analysis, the most used spectral method in science, generally boosts long-periodic noise in long gapped records; LSSA mitigates such problems.LSSA is also known as the Vaníček method after Petr Vaníček, and as the Lomb method (or the Lomb periodogram) and the Lomb–Scargle method (or Lomb–Scargle periodogram), based on the contributions of Nicholas R. Lomb and, independently, Jeffrey D. Scargle. Closely related methods have been developed by Michael Korenberg and by Scott Chen and David Donoho.

View More On Wikipedia.org
1. ### I Obtaining Transit Spectrum for Celestial Bodies Using JWST NIRSPEC

I've recently been tasked with obtaining transit spectrum data for some fascinating celestial bodies, including Ceres, Enceladus, Ganymede, Io, and Titan. The goal is to compare their transit spectra with that of Earth. However, I'm facing a bit of a challenge when it comes to using the Github...
2. ### A Extracting Color from a Spectral Date

Hello everybody, I would love some help on the following; I have a spectral date (As image 1 below) formed by the wavelength, refraction index and the absorption coefficient. Is there any way to relate this spectral date to a dominant wavelength? or in a few words extract the color from this...
3. ### How much does the equivalent width of a line change by the introduction of 5% scattered light?

How much does the equivalent width of a line change by the introduction of 5% scattered light? We know the equivalent width is defined as We know the equivalent width is defined as $$W = \int_{-\infty}^{\infty} \bigg(\frac{1-F_{\nu}}{F_c}\bigg) \, d\nu$$ where ##F_{\nu}## represents the flux in...
4. ### A Improper boundary in non-linear ODE (pseudospectral methods)

Hello, I am trying to compute some non-linear equations with pseudospectral/collocation methods. Basically I am expanding the solution as $$y(x)=\sum_{n=0}^{N-1} a_n T_n(x),$$ Being the basis an Chebyshev polynomial with the mapping x in [0,inf]. Then we put this into a general...

18. ### B What type of spectrum is a rainbow?

maybe it is emission spectrum of the sun but, seems continuous... unlike few distinct lines of the hydrogen emission spectrum...few images i just checked about it are similar to absorption spectrum...then maybe difraction could have made emission spectrum seem so or maybe not... Well I am very...
19. ### Photons emitted by Hydrogen and helium atoms

Homework Statement An excited hydrogen atom can emit photons of various wavelengths. a) What is the maximum wavelength of the Balmer series (in nm) (5pt) b) What is the minimum wavelength of the Balmer series (in nm) (5pt) c) Corresponding to part b), what is the kinetic energy of the recoil...
20. ### I How can larger dips in absorption line give more element

So I just learned that in a spectrum like this one: (For now, let's concentrate on the graph given below.) The longer the dip is in the graph, the more the corresponding element is present. However, if each individual color corresponds to a different element, then how can a larger dip mean...
21. ### A Basic Spectral Analysis proof help

I'm reading "Time Series Analysis and Its Applications with R examples", 3rd edition, by Shumway and Stoffer, and I don't really understand a proof. This is not for homework, just my own edification. It goes like this: Σt=1n cos2(2πtj/n) = ¼ ∑t=1n (e2πitj/n - e2πitj/n)2 = ¼∑t=1ne4πtj/n + 1 + 1...
22. ### Singular spectral analysis of periodic series with period L

Let's have a time series with a period=L. Suppose we arbitrarily choose the window length of the trajectory matrix to be equal to L which is also equal to the period of a time series. Then the second column of the matrix will also start with the same entry as the first column, because all...
23. ### Black-body radiation spectral analysis

Why is it that we observe a continuous spectrum in black-body radiation not discrete spectral lines dependent on the composition of the black-body? A niave understanding is that it relates to the complexity of the atomic structure of the black-body as well as thermal motion of its constiuent...
24. ### Spectral Analysis of Gas Atoms: Temperature Calculation

Hello Homework Statement A gas of atoms, each of mass m, is maintained in a box at temperature T. The atoms emit light which passes (in the x-direction) through a window in the box and can be observed as a spectral line in a spectroscope. A stationary atom would emit light at the sharply...
25. ### Spectral Analysis Applied to Ocean Waves

[b]1. I am currently looking at the area of spectral analysis applied to ocean waves. I have a set of "raw" recorded data of wave height, direction, frequency etc. I understand that spectral analysis is used to validate/process wave data recorded by instruments. [b]2. Have I more or less...
26. ### Spectral Analysis applied to ocean waves

Hi all, I would appreciate your guidance on the following: I am currently looking at the area of spectral analysis applied to ocean waves. I have a set of "raw" recorded data of wave height, direction, frequency etc. I understand that spectral analysis is used to validate/process wave data...
27. ### Proton NMR spectral analysis

Homework Statement Which isomer with formula C6H12O2 has the following NMR spectrum? http://aceorganic.pearsoncmg.com/epoch-plugin/tempfiles/1869_4119.jpg [b]3. The Attempt at a Solution It's hard (and probably unhelpful) to list all the tries I've had at this.
28. ### Measuring Power Spectral Analysis in dBvolts vs Frequency: Tips and Techniques

when looking at a power spectral analysis dBvolts vs frequency (Hz), how can you measure the area under the curve of a specific frequency range using the width at half height? any ideas?
29. ### Spectral analysis and displacement law

He everyone first of all, I am not quite sure, if I put this post in the correct topic, so sorry if that's the case. The things is, altough I don't go to school anymore I recently stumbled upon some theories and wanted to check them myself using the formulas that I could find on the net. I...
30. ### MATLAB MATLAB Spectral Analysis Code - Help Needed

Does someone have a code that would let me do a spectral analysis in MATLAB on a curve? I tried using fft but I can't get it to work.
31. ### Spectral Analysis: alternatives to Fourier Transforms?

hi, Could someone point me to some good material that relates to problems of (computational) spectral analysis? I understand FFT well enough, and although I'm not very good with math I'm willing to chew. What I'm seeking is some alternative approach to Fourier transformation (ie. from...