
Performance Verification
62
GTS1063 and GTS1250 GBIC Test Systems Instruction Manual
f.
Set the Vertical Offset to 0.0 V/div.
g. Set the Horizontal Size to 2 ns/div.
h. Set the oscilloscope record length to 5120 (maximum) points.
6. Perform the test with the following sequence on the oscilloscope:
a. Acquire the signal so that the first instance of the rising edge followed
by 4UI of high level (that is a 5-bit consecutive high sequence in the data
pattern) occurs midway in the first graticule on the left side of the
display (see Figure 28). This edge is the first positive going transition in
a K28.5-disparity 10-bit code group.
The figure shows the repeating Deterministic Jitter Test Pattern (K28.5)
and the oscilloscope crossing measurement being used to determine the
position of the first crossing point (edge #0: this point is used as the
reference crossing for the next 5 falling edges and 4 more rising edges)
NOTE
. The K28.5 Tx Pattern is a repeating 10-bit K28.5 —disparity code group
followed by a 10-bit K28.5 +disparity code group which results in a 20-bit
repeating pattern. Each instance of the 20-bit pattern in the waveform contains 5
positive going rising edges and 5 negative going falling edges. The following
procedure measures the relative occurrence of the 50% crossover point of each
of these edges relative to the rising edge in the middle of the first graticule
(known as edge #0 with a crossing time of T0). The term UI in the procedure
refers to Unit Interval and is the width of a single data bit (that is a 1250 Mb/s
NRZ data stream from a GTS1250 will have an ideal UI of 800 ps, while a
1062.5 Mb/s NRZ data stream from a GTS1063 will have an ideal UI of
941.176 ps).
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