User`s guide

Random Data with No Marker
Applications
• When a marker or bit clock is not available, such as live data on a network.
This tool is useful for diagnostics, but cannot be used for compliance testing.
Overview
This tool analyzes a single data signal. Because there is no bit clock or marker, the bit rate must be
entered in this tool very accurately. The measurement then assumes that this is the ideal bit rate and
measures the data relative to that ideal time. The tool must therefore make assumptions. The reported
DCD+DDJ value is the pk-to-pk of the histogram of Rising and Falling data edges rather than the worst-
case pk-pk values of the histograms of each edge (as it is in Known Pattern with Marker). The PJ
components can be seen on the FFT but the actual value of PJ is not displayed due to the presence of
frequency components from the data in addition to jitter. TJ is then only composed of the DJ from the
histogram and the 1-sigma RJ. Additionally, this tool can take up to 30 minutes to complete an
acquisition.
Measurments RDwNM Can Make
DCD + DDJ PJ DJ RJ TJ Views (Plots)
X X X DCD+DDJ
1 Sigma
FFT
Bathtub
Summary
Signal Requirements (1)Data Pattern
Benefits • Network/live traffic diagnostic/troubleshooting
Disadvantages • Absolute measured values may not be correct because algorithms
must make assumptions because the pattern is not known
• Spectral view includes jitter AND data components ·
© WAVECREST Corporation 2005 Section 4 - GigaView
155