The Pulse Repetition Interval (PRI) properties are described in this section and include PRI Pattern properties, PRI Jitter properties, and PRI Wobbulation properties.The PRI pattern properties enable you to vary the signal repetition interval in both random and deterministic ways. The PRI pattern can be applied to either a pulse object type or a pattern object type.You may specify a PRI pattern and apply both Jitter and Wobbulation impairments to it.
The PRI patterns include None, Bursted, Linear Ramp, Staggered, and Stepped. PRI Wobbulation is a periodic function and includes the types None, Sawtooth, Sinusoidal, and Triangular. PRI Jitter includes the types None, Gaussian, Uniformed, and U-Shaped . A unique PRI pattern can be applied to each pulse or pattern Object Type in the Pulse Building Pattern. If the Object Type is Off Time then the PRI pattern properties are ignored.
The PRI pattern is always generated during a download. Conflicts within the PRI pattern, PRI wobbulation, and PRI jitter are resolved in the following manner. Both the wobbulation and jitter impairment values are calculated assuming the current point in time is from an ideal pattern. The wobbulation and jitter impairments are added to the PRI pattern value. The combined PRI value is clipped such that it is equal to or greater than the full on time of the pulse being used. The full on time of the pulse is calculated assuming there is no pulse width pattern. The pulse width pattern is second to the PRI pattern and the full on time pulse width is clipped to the smaller of the pulse width or the actual PRI from the PRI pattern generator. That is to say, the PRI pattern is generated assuming a constant pulse width. The pattern values are clipped such that they are equal to or greater than the pulse width. Next, the pulse width pattern is generated. The pulse width pattern values are clipped such that they are equal to or less than the PRI for each pulse.
PRI patterns are restarted for each new item in the pattern table. This is not the case for pulse width patterns.
The Repeat property specifies the number of times to repeat the object type on a line by line basis. For example, a Stepped PRI pattern can be selected, but if the number entered for Repeat is set to one (1), no pattern is generated. The number of repeats is used to specify the number of times to repeat the object.
The PRI pattern is generated during a download. The pattern generator will clip values that are out of range. A common example of this is when the PRI pattern generator calculates a value that is smaller than the current full pulse on time. The pattern generator will return the larger of the value calculated or the full pulse on time. The signal will be generated unless the target hardware does not have the required capabilities.
For a PRI Pattern example, refer to the samples provided with the Pulse Building software at:
C:\Users\Public\Public Documents\Keysight\Pulse Building\Samples\pri_pattern_example\PulseBuilderPRIPatternExamples.docx
C:\Documents and Settings\All Users\Keysight\Pulse Building\Samples\pri_pattern_example\PulseBuilderPRIPatternExamples.docx