
Operating Basics
12
GTS1063 and GTS1250 GBIC Test Systems Instruction Manual
K28.5.
This is a mixed frequency test pattern. This pattern is intended to contain a
combination of both high frequency and low frequency patterns, and therefore
combine random jitter effects with deterministic jitter. (Deterministic jitter is
horizontal timing jitter of the data edges due to different patterns; asymmetry in
transmitters will exhibit noticeable deterministic jitter.) Use this signal to make
deterministic jitter measurements by averaging this signal to remove the random
jitter. For this pattern, the IEEE 802.3 (GTS1250) or Fibre Channel (GTS1063)
special code-group character K28.5 is used. The K28.5 negative disparity 10-bit
character (0011111010) is followed by the K28.5 positive disparity 10-bit
character (1100000101). The two 10-bit patterns are logical inversions of each
other. The K28.5 character ends with the opposite disparity that it begins with.
Thus the character repeated alternates between the two disparity versions of
itself.
LONG (GTS1250).
This is a complex continuous pattern for system jitter
measurements. The frequency spectrum content of this pattern is broad with
minimal peaking. The pattern is a valid packet of GBE data with full encapsula-
tion rules obeyed. The length of the pattern prior to 8B/10B encoding is
1536 bytes. (After 8B/10B encoding, the 1536 8-bit bytes would produce 1536
10-bit sequences, and therefore a total bit length of 15,360 bits.) The IEEE 802.3
standard defines the pattern prior to 8B/10B encoding, but the GTS1250 actually
transmits the 10B serial version adhering to both encapsulation and running
disparity rules.
The 8B/10B encoding and subsequent encapsulation of the packet is listed down
to the bit level in Appendix A on page 83.
CRPAT (GTS1063).
This Compliant Random Pattern is a complex continuous
pattern for system jitter measurements. The frequency spectrum content of this
pattern is broad with minimal peaking. The pattern is a valid Fibre Channel data
frame with full encapsulation rules obeyed.
The 8B/10B encoding and subsequent encapsulation of the packet is listed down
to the bit level in Appendix B on page 87.
SHORT (GTS1250).
This is a complex continuous pattern for system jitter
measurements. This pattern is similar to the LONG pattern, but with a shorter
loop length of the RPAT sequence. There are 372 8-bit bytes in the encapsulated
packet. (This produces a total bit length after 8B/10B encoding of 3720.)
The 8B/10B encoding and subsequent encapsulation of the packet is listed down
to the bit level in Appendix A on page 83.
CJTPAT (GTS1063).
This Compliant Jitter Tolerance Pattern is a complex
continuous pattern for system jitter measurements. The frequency spectrum
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