Sampling Interval

To change the sampling interval select this command from the Settings Menu. This will produce the "Set sampling interval" window displaying the current sampling interval. Edit a new value, which must not be less than 1.0e-8, and select OK. When the sampling interval is changed the function is resampled and redisplayed and the y-axis limits are reset to encompass the full range of values of y. The sampling interval cannot be changed for User-Defined Function.

To represent a signal, without aliasing, the sampling theorem states that the sampling interval cannot be more than 1/(2f) where f is the maximum frequency present in the signal. For instance the function cos(100*pi*t), where t is in seconds, represents a 50Hz signal of amplitude 1. This must be sampled with a sampling interval less than or equal to 1/(2*50)=0.01 seconds.

A smaller sampling interval will mean that the digital representation of the continuous function is more accurate. However a smaller sampling interval also means that more points are used to represent the function and this will mean that plotXpose will calculate and draw functions more slowly. The maximum number of points that plotXpose will allow in the discrete function definition is 4 096.

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