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tagwiki:tools:processing:comp_filt [2017/07/28 15:28] das39 [Matlab & Octave] |
tagwiki:tools:processing:comp_filt [2021/06/07 15:21] sbf5 [R] fixed `fs`. we're moving away from this abbreviation, should be `sampling_rate` |
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| + | =====comp_filt===== | ||
| + | Complimentary filtering of a signal | ||
| + | ----- | ||
| + | ===== Syntax ===== | ||
| + | === Matlab & Octave === | ||
| + | <code> | ||
| + | Xf = comp_filt(X,fs,fc) % X is a vector or matrix | ||
| + | or | ||
| + | Xf = comp_filt(X,fc) % X is a signal structure | ||
| + | </code> | ||
| + | ===R=== | ||
| + | <code> | ||
| + | Xf <- comp_filt(X,fs,fc) % X is a vector or matrix | ||
| + | or | ||
| + | Xf <- comp_filt(X,fc) % X is a signal list | ||
| + | </code> | ||
| + | |||
| + | |||
| + | ===== Description ===== | ||
| + | Complimentary filtering of a signal. This breaks signal X into two or more frequency bands such that the sum of the signals in the separate bands is equal to the original signal. | ||
| + | |||
| + | ===== Inputs ===== | ||
| + | ^ Input var ^ Description ^Units ^Default value ^ | ||
| + | | X | is a sensor vector or matrix (i.e., with a signal in each column), or a sensor structure. | N/A | N/A | | ||
| + | | fs | is the sampling rate of the sensor data (samples per second). fs is only needed if X is not a sensor structure. | Hz | N/A | | ||
| + | | fc | specifies the cut-off frequency or frequencies of the complimentary filters. If one frequency is given, X will be split into a low- and a high-frequency component. If fc contains more than one value, X will be split into multiple complimentary bands. Each filter length is 4*fs/fc. Filtering adds no group delay | Hz | N/A | | ||
| + | |||
| + | ===== Outputs ===== | ||
| + | ^ Output var ^ Description ^ Units^ | ||
| + | |Xf| is a cell array of filtered signals. There are n+1 cells where n is the length of fc. Cells are ordered in Xf from lowest to highest frequency. Each cell contains a vector or matrix of the same size as X, and at the same sampling rate as X. | Hz | | ||
| + | |||
| + | ===== Notes & assumptions ===== | ||
| + | ===== Example ===== | ||
| + | |||
| + | ==== Matlab & Octave ==== | ||
| + | The example below uses data from the file testset1.nc. | ||
| + | You can download it from the [[http://www.animaltags.org./doku.php?id=tagwiki:datasets|animaltags website's example data sets]]. | ||
| + | If the file is saved in your current working directory, load it via: | ||
| + | <code> | ||
| + | testset1 = load_nc(‘testset1.nc’) | ||
| + | </code> | ||
| + | <code> | ||
| + | Xf = comp_filt(testset1.A.data, testset1.A.sampling_rate, 0.8) | ||
| + | plott(Xf{1,1}, testset1.A.sampling_rate, Xf{1,2}, testset1.A.sampling_rate) | ||
| + | </code> | ||
| + | ==== R ==== | ||
| + | The example below uses data from the file testset1.nc. | ||
| + | You can download it from the [[http://www.animaltags.org./doku.php?id=tagwiki:datasets|animaltags website's example data sets]]. | ||
| + | If the file is saved in your current working directory, load it via: | ||
| + | <code> | ||
| + | testset1 <- load_nc(‘testset1.nc’) | ||
| + | </code> | ||
| + | <code> | ||
| + | Xf <- comp_filt(X = testset1$A$data, sampling_rate = testset1$A$sampling_rate, fc = .8) | ||
| + | xf <- list(Xf1 = Xf[[1]], Xf2 = Xf[[2]]) | ||
| + | plott(xf, testset1$A$sampling_rate) | ||
| + | </code> | ||
| + | |||
| + | ===== About ===== | ||
| + | [[bugs@animaltags.org]] | ||
| + | Last modified: 2 July 2017 | ||