VeEX MTX150 Series, User Manual

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Fiber Channel © VeEX Inc. All Rights Reserved. 210
FC-2 BERT - EOF Setup
Payload
The test set implements and observes "Methodologies for Jitter and Signal Quality Specification (MJSQ)". A
major goal of MJSQ is to improve the relationship between measurements on signals and receiver per-
formance in terms of bit errors. The unit transmits a "compliant pattern" which consists of a valid Fiber Channel
protocol frame (SOF, payload, CRC, EOF) containing a test pattern as the payload. Different payload selec-
tions are available depending on the Fiber Channel layer to be tested. The payload consists of 0 to 2112 bytes,
and is sent in 4 byte increments, otherwise it is considered to be a misaligned frame.
FC-1 Payload (test pattern)
Layer 1 test patterns are formatted using the 8B/10B symbol format and include the PCS layer as part of the
BER pattern.
CRPAT, CSPAT, and CJTPAT test patterns according to NCITS-TR-25-1999 and MJSQ, are designed to eval-
uate frequency fluctuations, transceiver noise and phase jumps caused by jitter and other anomalies. These
test patterns are described briefly as follows:
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CSPAT: Compliant Supply Noise Pattern
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Represents worst case power supply noise
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CRPAT: Compliant Random Pattern
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Provides broad spectral content and minimal peaking for the measurement of jitter at com-
ponent or system level
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CJTPAT: Compliant Jitter Test Pattern
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Jitter Tolerance Pattern that stresses a receiver by exposing it to extreme phase jumps
thereby stressing the clock data recovery (CDR) circuitry
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The pattern alternates between repeating low transition density patterns and repeating high
transition density patterns