:MEASure:JITTer:JITTer:RJBandwidth

Command Syntax

:MEASure:JITTerN:JITTer:RJBandwidth {WIDE | NARRow}

Where N identifies one of four possible jitter/noise analyses {1:4}. For example, JITTer4.

Query Syntax

:MEASure:JITTerN:JITTer:RJBandwidth?

Description

The Jitter analysis software uses a spectral technique to separate RJ from PJ.

Narrow bandwidth spikes that extend above the jitter spectrum's baseline are considered to contain PJ, while the remaining baseline is assumed to contain only RJ. This technique works very well for wide-bandwidth (white) random jitter.

Wide bandwidth RJ has a uniform power spectral density (PSD) across the entire jitter spectrum. Sometimes however, the RJ being measured does not have a uniform PSD. Although this is not as common in practical communication system applications, it does occur frequently in jitter sources generated using laboratory test equipment.

Conversely, the jitter spectrum of some PJ components appears much broader than the narrow spikes of a highly periodic jitter component. These broad-bandwidth PJ components are also uncommon, but they can be difficult to distinguish from RJ by inspecting the jitter spectrum alone.

For these reasons, this command lets you specify whether you want to treat "broad lumps" in the jitter spectrum as RJ or PJ:

WIDE

Setting the RJ Bandwidth mode to wide (white) assumes that the RJ is flat, and that all broad lumps in the jitter spectrum are considered to be PJ.

NARRow

Setting the RJ Bandwidth mode to narrow (pink) acknowledges that the RJ may or may not be flat, and that all broad lumps in the jitter spectrum are considered to be RJ.

By default, the RJ bandwidth mode is set to narrow (pink).

The Jitter analysis uses a non-linear decision threshold that can follow the non-flat baseline of RJ. This non-linear threshold is only used in narrow RJ Bandwidth mode because the wide RJ bandwidth mode tells the analysis that you already know that the RJ baseline is flat with frequency.