crplot: Function to plot a digital sinusoid and the circle from which it is derived.

Description

A digital sinusoid is derived the movement of a point around a circle. The function shows the relationship between the two for various parameter settings.

Usage

crplot(
  A = 1,
  k = 1,
  p = 0,
  N = 16,
  const = NULL,
  figsize = 8,
  npoints = 500,
  col = 1,
  cplot = TRUE,
  splot = TRUE,
  numplot = TRUE,
  axes = TRUE,
  incircle = TRUE,
  arrow = TRUE,
  linetype = 1,
  textplot = NULL,
  lineplot = NULL,
  ylab = "Amplitude",
  super = NULL,
  xaxlab = NULL,
  type = "b",
  xlab = "Time (number of points)",
  fconst = 3.5/3.1,
  pointconst = 1.2
)

Arguments

A: Amplitude of the circle/sinusoid.
k: Frequency of the sinusoid
p: Phase of the sinusoid
N: Number of points per cycle or revolution.
const: A constant corresponding to k + A*cos(2*pi*k+p)
figsize: Set the figure size as pin <- c(figsize, figsize/2). Defaults to figsize = 8.
npoints: The number of points used in plotting the circle. Defaults to 500
col: An integer for the color in plotting the sinusoid and points around the circle
cplot: Now redundant
splot: Now redundant
numplot: Logical. If TRUE (defaults), the digital points around the circle are numbered
axes: Logical. If TRUE, plot axes.
incircle: Logical. If TRUE, plot an the angle between digital points in the circle.
arrow: Logical. If TRUE, plot an arrow on incircle showing the direction of movement.
linetype: Specify a linetype. Same function as lty in plot
textplot: A list containing $radius, $textin, $pivals for plotting text at specified angles and radii on the circle. $radius: a vector of amplitudes of the radii at which the text is to be plotted; $textin: a vector of character labels to be plotted; $pivals: the angle, in radians relative to zero radians (top of the circle) at which the text is to be plotted. Defaults to NULL
lineplot: Plot lines from the centre of the circle to the circumference. lineplot is a vector specifying the angle in radians (zero corresponds to the top of the circle)
ylab: Specify a y-axis label.
super: Superimpose a part solid circle and corresponding sinusoid. This needs to be a list containing $first and $last, which are values between 0 and 2*pi defining the beginning and ending of the part circle which is to be superimposed
xaxlab: Now redundant
type: Specify a type.
xlab: Specify an x-axis label.
fconst: A single element numeric vector for the aspect ratio in a postscript plot. Defaults to 3.5/3.1 which is appropriate for a postscript setting of setps(h=4, w=4)
pointconst: The radius for plotting the numbers around the circle. Defaults to 1.2 * A

Author

Jonathan Harrington

References

Harrington, J, & Cassidy, S. 1999. Techniques in Speech Acoustics. Kluwer

Examples

Run this code


crplot()
# sine wave
crplot(p=-pi/2)

crplot(k=3)

# aliasing
crplot(k=15)