User`s guide

Data Tools
Data Tools Overview
There are different tools available for measuring data signals. Each tool requires specific signal types to
provide measurements. Choosing the right tool depends on what signals you have or are capable of
producing and what information you wish to get from the tool. Each tool section includes a table that
shows which measurements are made by each tool, the Views available, the signal types and benefits
and disadvantages of using a particular tool.
Known Pattern with Marker
This tool provides the fastest, most complete measurements for compliance testing. Histograms of every
edge in the pattern are made in order to determine DCD+ISI. Spectral content is measured to determine
PJ contribution and in the presence of significant PJ, TailFit can be enabled to determine a more accurate
RJ. TJ is based on the convolution of DJ and RJ values.
Random Data with Bit Clock
This tool makes measurements relative to a bit-clock. Therefore modulation or PJ cannot be determined.
Similarly because the histogram is composed of many different data transitions, the DCD+ISI value is not
directly determined. The DJ, RJ and TJ values are determined from a TailFit on the histogram of Rising
and Falling data edges.
Random Data with No Marker
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+ISI 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 1sigma RJ. Additionally, this tool can take up to 30 minutes to complete an
acquisition.
Known Pattern with Bit Clock and Marker
In addition to the data signal to be analyzed, this tool requires a pattern connected to an Arm channel,
along with a bit clock supplied to another channel. If your system has a PM-50 card installed, you can
connect the data signal directly to channel 1. The Bit clock can either be generated internal to the SIA-
3000 (if you have the Clock to Data Recovery module installed on your system) or from an external
source. The marker signal has an edge relative to the same bit of the pattern each time the marker
occurs. Since a bit clock is also used, the ideal UI width is measured not calculated.
© WAVECREST Corporation 2005 Section 4 - GigaView
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