SLK2511 Datasheet, PDF (12/21 Pages) Texas Instruments – OC-48/24/12/3 SONET/SDH MULTIRATE TRANSCEIVER

SLK2511
OC-48/24/12/3 SONET/SDH MULTIRATE TRANSCEIVER
SLLS522A – JUNE 2002 – REVISED OCTOBER 2002
detailed description (continued)
SRXDIP
D
SRXDIN
Recovered Clock
1:4 Serial to
Parallel
LLOOP
STXDOP
D
STXDON
4:1 Parallel to
Serial
RXDATA (3–0)
RXCLK
TXDATA (3–0)
TXCLK
2.488 GHz
PLL
Figure 4. Local Loopback Data Path
remote loopback
The RLOOP signal pin controls the remote loopback. When RLOOP is high, the serial receive data is selected
and presented on the serial transmit data output pins. The serial received data is also demultiplexed and
presented on the parallel receive data pins. The remote loop can be enabled only when the device is under
transceiver mode. When the device is put under the repeater mode with RX_MONITOR high, it performs the
same function as the remote loopback.
SRXDIP
D
SRXDIN
Recovered Clock
1:4 Serial to
Parallel
RXDATA (3–0)
RXCLK
STXDOP
D
STXDON
4:1 Parallel to
Serial
LLOOP
2.488 GHz
PLL
Figure 5. Remote Loopback Data Path/Repeater Mode Operation
PRBS
The SLK2511 has two built-in pseudorandom bit stream (PRBS) functions. The PRBS generator is used to
transmit a PRBS signal. The PRBS verifier is used to check and verify a received PRBS signal.
When the PRBSEN pin is high, the PRBS generator and verifier are both enabled. A PRBS is generated and
fed into the parallel transmitter input bus. Data from the normal input source is ignored in PRBS mode. The
PBRS pattern is then fed through the transmitter circuitry as if it was normal data and sent out by the transmitter.
The output can be sent to a bit error rate tester (BERT) or to the receiver of another SLK2511. If an error occurs
in the PRBS pattern, the PRBSPASS pin is set low for 2 RXCLKP/N cycles.
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