VeEX VePAL TX300M, Руководство пользователя

Страница: 389 / 421

Go back to top Go back to TOC
Payload
The TX300/e 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 performance 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 selections 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 evaluate frequency
fluctuations, transceiver noise and phase jumps caused by jitter and other anomalies. These test patterns are described briefly as
follows:
CSPAT:
Compliant Supply Noise Pattern
Represents worst case power supply noise
CRPAT:
Compliant Random Pattern
Provides broad spectral content and minimal peaking for the measurement of jitter at component or system level
CJTPAT:
Compliant Jitter Test Pattern
Jitter Tolerance Pattern that stresses a receiver by exposing it to extreme phase jumps thereby stressing the clock data
recovery (CDR) circuitry
The pattern alternates between repeating low transition density patterns and repeating high transition density patterns
FC-1 BERT - Payload Setup
TX300S_e-manual_D07-00-064P_RevA00