# plot.spec

##### Plotting Spectral Densities

Plotting method for objects of class `"spec"`

. For multivariate
time series it plots the marginal spectra of the series or pairs plots
of the coherency and phase of the cross-spectra.

##### Usage

```
# S3 method for spec
plot(x, add = FALSE, ci = 0.95, log = c("yes", "dB", "no"),
xlab = "frequency", ylab = NULL, type = "l",
ci.col = "blue", ci.lty = 3,
main = NULL, sub = NULL,
plot.type = c("marginal", "coherency", "phase"),
…)
```plot.spec.phase(x, ci = 0.95,
xlab = "frequency", ylab = "phase",
ylim = c(-pi, pi), type = "l",
main = NULL, ci.col = "blue", ci.lty = 3, …)

plot.spec.coherency(x, ci = 0.95,
xlab = "frequency",
ylab = "squared coherency",
ylim = c(0, 1), type = "l",
main = NULL, ci.col = "blue", ci.lty = 3, …)

##### Arguments

- x
an object of class

`"spec"`

.- add
logical. If

`TRUE`

, add to already existing plot. Only valid for`plot.type = "marginal"`

.- ci
coverage probability for confidence interval. Plotting of the confidence bar/limits is omitted unless

`ci`

is strictly positive.- log
If

`"dB"`

, plot on log10 (decibel) scale (as S-PLUS), otherwise use conventional log scale or linear scale. Logical values are also accepted. The default is`"yes"`

unless`options(ts.S.compat = TRUE)`

has been set, when it is`"dB"`

. Only valid for`plot.type = "marginal"`

.- xlab
the x label of the plot.

- ylab
the y label of the plot. If missing a suitable label will be constructed.

- type
the type of plot to be drawn, defaults to lines.

- ci.col
colour for plotting confidence bar or confidence intervals for coherency and phase.

- ci.lty
line type for confidence intervals for coherency and phase.

- main
overall title for the plot. If missing, a suitable title is constructed.

- sub
a sub title for the plot. Only used for

`plot.type = "marginal"`

. If missing, a description of the smoothing is used.- plot.type
For multivariate time series, the type of plot required. Only the first character is needed.

- ylim, …
Graphical parameters.

##### See Also

*Documentation reproduced from package stats, version 3.5.0, License: Part of R 3.5.0*