similar to: Question on harmonic (Fourier) analysis of sinusoidal time series

Hi, Suppose x and y are vectors whose elements are known. I know that there is a sinusoidal relation between them. In other words, y=a*sin(bx) where b is probably a function of pi. How do I find a and b in R? Hakan [[alternative HTML version deleted]]

Hi Guys, I had a monthly time series's data of land temperature from 1980 to 2008. After plotting a scatter diagram, it seems that annually, there is a semi sinusoidal cycle. How do I run Fourier's series to the data so that I can fit model on it? I am really sorry for my question sound stupid, but I just don't know where to start. I am desperately looking for help from you guys.

well if you want to find the spectral density aka what frequencies explain most of the variance then I would suggest the spectral density. This can be implemented with spec.pgram(). This is conducted with the fast fourier transform algorithm. a<-ts(data, frequency = 1) #make the time series with 365readings/365days ?spec.pgram and you should be able to take it from here This will

Dear List, I am attempting to perform a harmonic analysis on a time series of snow depth, in which the annual curve is essentially asymmetric (i.e. snow accumulates slowly over time, and the subsequent melt occurs relatively rapidly). I am trying to fit a curve to the data, however, the actual frequency is unknown. I have been trying to follow the methods in Peter Bloomfields text

Hello, I try to synthesize harmonic functions with a subset of frequencies determined by fast fourier transform. I wrote two different functions, a looped version and a matrix multiplication version. As an example the looped version takes 5 sec and the matrix-version takes 3-4 sec (R 1.4, Athlon 1.2 GHz, 256 MB, Win ME), but the latter needs huge amount of memory due to the matrices. So, none of

Dear R Users, I have a CO2 time series. I want to fit this series seasonal cycle and trend with fourth harmonic function, and then compute residuals. I am doing something like: file<-read.csv("co2data.csv") names(file) attach(file) fit<-lm(co2~1+time+I(time^2)+sin(2*pi*time)+cos(2*pi*time)+sin(4*pi*time)+cos(4*pi*time)+

Dear All, I have some time series data where X=month and Y=nutrient concentration (I can have several concentration data for one month). Is there a way to fit for it an Harmonic Function. Is there a package, script,etc which I can use? Thx -- View this message in context: http://r.789695.n4.nabble.com/Fitting-a-Harmonic-Function-to-Time-Series-Data-tp3901266p3901266.html Sent from the R help

I am looking for a package to perform harmonic analysis with the goal of estimating the period of the dominant high frequency component in some mono-channel signals. I guess there are presumably a number of CRAN packages allowing for such analysis. However, my search with keywords was not successfull. It brought up a lot of Fourier miscellanea but nothing specifically geared for my needs. I would

Dear all: Does anyone has harmonic regresssion analysis package written in R (to be used in Windows platform) ? Thanks _______________________________________ YM - Â÷½u°T®§ ´Nºâ§A¨S¦³¤Wºô¡A§AªºªB¤Í¤´¥i¥H¯d¤U°T®§µ¹§A¡A·í§A¤Wºô®É´N¯à¥ß§Y¬Ý¨ì¡A¥ô¦ó»¡¸Ü³£ÉN¨«¥¢¡C http://messenger.yahoo.com.hk [[alternative HTML version deleted]]

Hello list; I am working with a dataset containing animal locations over time for a large number of individuals. I would like to compute a center of activity by finding the minimum harmonic mean on a grid overlaying the points of an animal (a "standard" to express center of activity in animal ecology). I have searched the archives at Jonathan Barons server but have not been able

I' need to smooth a serie univariate with harmonic regression, but i do not know if it exists somepeople know in R this type of regression, not in S-plus. Thank's _________________________________________________________

Hi, Sorry for the very short explanation about the problem of intersection. I have a wave function monitored from the heart beat in a particular interval of times.?Apart?fom that, there is?a line with positive slope (e.g: y = x+2) which lies across the wave and intersect on a number of points. My problem is i have no exact equation for?such a?complex harmonic wave produced by the heart

Hi, here is a practical problem we would like to solve. In a pneumatic post the acceleration of the capsule is measured and plotted over time. From the graph achieved we would like to derive some kind of statistic value that describes the stress the capsule, or what is in it, is exhibited to. The amount of stress introduced to the capsule will probably depend on two things, the maximum

Hello, I'm working on a very large project in which we do many calculations which include many types of regression such as, Liner, Quadratic, Cubic, Exponential, Sinusoidal, and Logarithmic. Im well aware that its easy enough to do Linear regression in R but what about the other types? I've been searching on google for such functions but to no avail. Thank you, -- Samuel Bravo

An idea would be like for WMA 9 lower bitrates (32-42-48Kbps) to use a 'crystallizer'; which is basically a harmonics booster focussed at transposing sharp tones some octaves higher. Eg: A file has been recorded @ 20khz computer (or 10khz real life) to preserve space. While playing back the file sounds a bit mushy, almost as if someone was speaking through a cardboard wall. The higher

Running R version 2.6.1 under Linux, I'm trying to use the maps and mapdata packages and the state database to produce a thematic map of the USA. My problem is that cracks (white spaces) appear between some states--e.g. between Colorado and Utah and between Michigan and Indiana. The resulting visual impression is that the country is breaking up. This occurs in all the projections I have

Hello, the only thing I found to fit a sin/cos is s.th like lm(a~cos+sin) But this is not what I want. I have a magnitude which is sinusoidal with offset and it doesn't start at phi=0. The data is: angle<-c(0,10,20,30,40,50,60,70,80,90,100,110,120,130,140,150,160,170,180) Voltage<-c(-45.07, -45.24, -43.61, -40.78, -36.48, -30.92, -23.83, -15.95, -7.53, 1.06, 11.24,19.85, 27.00,

Hello! I'm collecting data on a refrigerator that I'm using to cure meat. Specifically I am collection humidity and temperature readings. The temperature readings look sinusoidal (due to the refrigerator turning on and off). I'd like to calculate the frequency and period of the wave so that I can determine if modifications I make to the equipment are increasing or decreasing

Hello, In doing a series of non-linear estimations of a function which is a sum of a varying number of sinusoids, I would like to "autogenerate" the arguments needed by nls() depending on that number. For example, when there are two sinusoids: > nls( y ~ mu + A1 * cos(2*pi*f1*x - P1) + A2 * cos(2*pi*f2*x - P2), data = some.xy.data, start = list( mu=some.value0,

Hi Has anybody done THD or THD-N measurements with the CELT Codec (bext would be on various bit rates) If someone could share results for Mono at 64kBit and Stereo at 128 and 196kBit it would be great. thank you very much Jochen -------------- next part -------------- An HTML attachment was scrubbed... URL: http://lists.xiph.org/pipermail/opus/attachments/20100817/b1da17cc/attachment-0002.htm