periodogram-methods(tuneR)
periodogram-methods()所属R语言包：tuneR
Periodogram (Spectral Density) Estimation on Wave objects
周期图（谱密度）估计海浪对象
译者：生物统计家园网 机器人LoveR
描述----------Description----------
This function estimates one or more periodograms (spectral densities) of the time series contained in an object of class Wave (or directly in a Wave file) using a window running through the time series (possibly with overlapping).
此函数估计的一个或多个周期图（谱密度）的时间序列中包含的一个对象的类Wave（或直接在Wave文件）使用时间序列（可能有重叠）通过运行一个窗口。
用法----------Usage----------
periodogram(object, ...)
## S4 method for signature 'Wave'
periodogram(object, width = length(object), overlap = 0,
starts = NULL, ends = NULL, taper = 0, normalize = TRUE,
frqRange = c(-Inf, Inf), ...)
## S4 method for signature 'character'
periodogram(object, width, overlap = 0, from = 1, to = Inf,
units = c("samples", "seconds", "minutes", "hours"),
downsample = NA, channel = c("left", "right"), pieces = 1, ...)
参数----------Arguments----------
参数：object
An object of class Wave or a character string pointing to a Wave file.
对象的类Wave或字符的字符串，指向一个Wave文件。
参数：width
A window of width "width" running through the time series selects the samples from which the periodograms are to be calculated.
一个窗口的宽度“width在时间序列中选择运行的周期图来计算的样本。
参数：overlap
The window can be applied by each overlapping overlap samples.
该窗口可以由每个重叠overlap样品施加。
参数：starts
Start number (in samples) for a window. If not given, this value is derived from argument ends, or will be derived width and overlap.
一个窗口启动号码（样本）。如果没有给出，这个值是来自参数ends，或将衍生width和overlap。
参数：ends
End number (in samples) for a window. If not given, this value is derived from argument starts, or will be derived from width and overlap.
结尾号码（样本）的一个窗口。如果没有给出，这个值是来自参数starts，或将来自width和overlap。
参数：taper
proportion of data to taper. See spec.pgram for details.
数据的锥度比例。见spec.pgram的详细信息。
参数：normalize
Logical; if TRUE (default), two steps will be applied: (i) the input signal will be normalized to amplitude max(abs(amplitude)) == 1, (ii) the resulting spec values will be normalized to sum up to one for each periodogram.
逻辑，如果TRUE（默认），两个步骤将适用于：（一）将被标准化为输入信号的振幅max(abs(amplitude)) == 1，（ii）本spec值将归到总结为每个周期图之一。
参数：frqRange
Numeric vector of two elements indicating minimum and maximum of the frequency range that is to be stored in the resulting object. This is useful to reduce memory consumption.
两个元素，指示是要被存储在所产生的对象的频率范围的最小值和最大值的数值向量。这是非常有用的，以减少内存消耗。
参数：from
Where to start reading in the Wave file, in units.
从哪里开始读的Wave文件，在units。
参数：to
Where to stop reading in the Wave file, in units.
停止中的Wave文件读取，units。
参数：units
Units in which from and to is given, the default is “samples”, but can be set to time intervals such as “seconds”, see the Usage Section above.
单位from和to的，默认为“样本”，但可以设置时间间隔，如“秒”，看到上面的用法“一节。
参数：downsample
Sampling rate the object is to be downsampled to. If NA, the default, no changes are applied. Otherwise downsample must be in [2000, 192000]; typical values are 11025, 22050, and 44100 for CD quality. See also downsample.
采样率的对象是被向下取样，以。如果NA，默认情况下，不进行任何更改应用。否则downsample必须在[2000, 192000]典型值分别为11025，22050和44100的CD质量。 downsample。
参数：channel
Character, indicating whether the “left” or “right” channel should be extracted (see mono for details) - stereo processing is not yet implemented.
字符，表示“左”或“右”通道是否应提取（见mono） - 立体声处理还没有实现。
参数：pieces
The Wave file will be read in in pieces steps in order to reduce the amount of required memory.
WAVE文件将被读入pieces步骤，以减少所需的内存量。
参数：...
Further arguments to be passed to the underlying function spec.pgram.
进一步的参数被传递到底层函数spec.pgram。
值----------Value----------
An object of class Wspec is returned containing the following slots. <table summary="R valueblock"> <tr valign="top"><td>freq</td> <td> Vector of frequencies at which the spectral density is estimated. See spectrum for details. (1)</td></tr> <tr valign="top"><td>spec</td> <td> List of vectors or matrices of the spec values returned by spec.pgram at frequencies corresponding to freq. Each element of the list corresponds to one periodogram estimated from samples of the window beginning at start of the Wave object.</td></tr> <tr valign="top"><td>kernel</td> <td> The kernel argument, or the kernel constructed from spans returned by spec.pgram. (1)</td></tr> <tr valign="top"><td>df</td> <td> The distribution of the spectral density estimate can be approximated by a chi square distribution with df degrees of freedom. (1)</td></tr> <tr valign="top"><td>taper</td> <td> The value of the taper argument. (1)</td></tr> <tr valign="top"><td>width</td> <td> The value of the width argument. (1)</td></tr> <tr valign="top"><td>overlap</td> <td> The value of the overlap argument. (1)</td></tr> <tr valign="top"><td>normalize</td> <td> The value of the normalize argument. (1)</td></tr> <tr valign="top"><td>starts</td> <td> If the argument starts was given in the call, its value. If the argument ends was given in the call, "ends - width". If neither starts nor ends was given, the start points of all periodograms. In the latter case the start points are calculated from the arguments width and overlap.</td></tr> <tr valign="top"><td>stereo</td> <td> Whether the underlying Wave object was stereo ot not. (1)</td></tr> <tr valign="top"><td>samp.rate</td> <td> Sampling rate of the underlying Wave object. (1)</td></tr> <tr valign="top"><td>variance</td> <td> The variance of samples in each window, corresponding to amplitude / loudness of sound.</td></tr> <tr valign="top"><td>energy</td> <td> The “energy” E, also an indicator for the amplitude / loudness of sound:
一个对象的类Wspec的返回包含以下插槽。 <table summary="R valueblock"> <tr valign="top"> <TD>freq</ TD> <TD>向量的频率的功率谱密度估计。见spectrum的详细信息。 （1）</ TD> </ TR> <tr valign="top"> <TD> spec </ TD> <TD>的spec值的向量或矩阵列表返回 spec.pgram在freq频率对应。的列表中的每个元素对应于一个周期图估计从样品开始的窗口在startWave对象。</ TD> </ TR> <tr valign="top"> <TD> kernel</ td> <td>使用内核参数，或者返回spec.pgram的跨度构造的内核。 （1）</ TD> </ TR> <tr valign="top"> <TD>df </ TD> <TD>的分布谱密度估计可以近似卡方分布df自由度。 （1）</ TD> </ TR> <tr valign="top"> <TD>taper </ TD> <TD>的taper参数的值。 （1）</ TD> </ TR> <tr valign="top"> <TD>width </ TD> <TD>的width参数的值。 （1）</ TD> </ TR> <tr valign="top"> <TD>overlap </ TD> <TD>的overlap参数的值。 （1）</ TD> </ TR> <tr valign="top"> <TD>normalize </ TD> <TD>的normalize参数的值。 （1）</ TD> </ TR> <tr valign="top"> <TD> starts </ TD> <TD>如果参数starts在调用它的价值。如果参数ends在通话时，ends - width。如果没有starts，也不ends是给定的，所有周期图的起始点。在后一种情况下开始点计算参数width和overlap。</ TD> </ TR> <tr valign="top"> <TD>stereo</ TD> <TD>是否有潜在的Waveobject立体声OT没有。 （1）</ TD> </ TR> <tr valign="top"> <TD>samp.rate </ TD> <TD>采样率的基础Waveobject。 （1）</ TD> </ TR> <tr valign="top"> <TD>variance</运输署> <td>使用在每个窗口中的样本方差，对应的振幅/声音的响度。 </ TD> </ TR> <tr valign="top"> <TD> energy</ TD> <TD>的“能量”E，也是一个指标的振幅/音量的声音：
E(x_I) := 20 * log_{10} sum_{j in I} |x_j|,</i>
E（x_i的）：= 20 * LOG_ {10} sum_ {j在I} | x_j |，</ I>
注意----------Note----------
Support for processing of stereo Wave objects has not yet been implemented.
支持立体声处理的Wave对象没有尚未实施。
（作者）----------Author(s)----------
Uwe Ligges, <a href="mailto:ligges@statistik.tu-dortmund.de">ligges@statistik.tu-dortmund.de</a>
参见----------See Also----------
实例----------Examples----------
# constructing a Wave object (1 sec.) containing sinus sound with 440Hz:[构建一个Wave对象（1秒）。窦与440Hz的声音：]
Wobj <- sine(440, bit = 16)
Wobj
# Calculate periodograms in windows of 4096 samples each - without[计算周期图中每4096个样本的窗口 - 无]
# any overlap - resulting in an Wspec object that is printed:[任何重叠 - 导致那是印的一个Wspec对象：]
Wspecobj <- periodogram(Wobj, width = 4096)
Wspecobj
# Plot the first periodogram from Wspecobj:[从Wspecobj绘制的第一个周期图：]
plot(Wspecobj)
# Plot the third one and choose a reasonable xlim:[绘制第三个，选择合理的作适当调整：]
plot(Wspecobj, which = 3, xlim = c(0, 1000))
# Mark frequency that has been generated before:[马克频率之前已生成：]
abline(v = 440, col="red")
FF(Wspecobj) # all ~ 440 Hertz[~440赫兹]
noteFromFF(FF(Wspecobj)) # all diapason a[所有的和谐一]
转载请注明:出自 生物统计家园网(http://www.biostatistic.net)。
注：
注1：为了方便大家学习，本文档为生物统计家园网机器人LoveR翻译而成，仅供个人R语言学习参考使用，生物统计家园保留版权。
注2：由于是机器人自动翻译，难免有不准确之处，使用时仔细对照中、英文内容进行反复理解，可以帮助R语言的学习。
注3：如遇到不准确之处，请在本贴的后面进行回帖，我们会逐渐进行修订。
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发表于 2012-10-1 13:02:34
