
Table 37: Supported PRBS Patterns (cont'd)
Name
Polynomial
Length of
Sequence
Description
PRBS-9
1 + x
5
+ x
9
2
9
– 1 bits
ITU-T Recommendation O.150, Section 5.1. PRBS-9 is one
of the recommended test patterns for SFP+.
PRBS-13
1 + x + x
2
+ x
12
+ x
13
2
9
– 1 bits
IEEE Std P802.3bs D3.5 test requires QPRBS-13 test
pattern.
PRBS-15
1 + x
14
+ x
15
2
15
– 1 bits
ITU-T Recommendation O.150, Section 5.3. PRBS-15 is
often used for jitter measurement because it is the
longest pattern the Agilent DCA-J sampling scope can
handle.
PRBS-23
1 + x
18
+ x
23
2
23
– 1 bits
ITU-T Recommendation O.150, Section 5.6. PRBS-23 is
often used for non-8B/10B encoding schemes. It is one
of the recommended test patterns in the SONET
specification.
PRBS-31
1 + x
28
+ x
31
2
31
– 1 bits
ITU-T Recommendation O.150, Section 5.8. PRBS-31 is
often used for non-8B/10B encoding schemes. It is a
recommended PRBS test pattern for 10 Gigabit Ethernet.
See IEEE Std 802.3ae-2002.
IMPORTANT! For PAM4 modulation, QPRBS patterns are supported by sending a conventional PRBS
pattern with PAM4 and Gray Coding based on the OIF2014.230 CEI-56G-VSR-PAM4 specification.
In addition to PRBS patterns, the GTM transceiver supports a 64 UI square wave test pattern as
shown in the following figure, an alternating
1’b0
and
1’b1
(NRZ clock) test pattern. Clocking
patterns are usually used to check PLL random jitter often done with a spectrum analyzer.
Note
:
For PAM4 modulation, an alternating
1’b0
and
1’b1
test pattern will not be a square wave due to
the amplitude modulation mapping.
Figure 31:
64 UI Square Wave
64 UI
X22031-112618
The error insertion function is also supported to verify link connection for jitter tolerance tests.
When an inverted PRBS pattern is necessary, the CH[0/1]_TXPOLARITY signal is used to control
polarity.
Chapter 3: Transmitter
UG581 (v1.0) January 4, 2019
Virtex Ult GTM Transceivers
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