XRT83SL38IB View Datasheet(PDF) - Exar Corporation
Part Name
Description
MFG CO.
'XRT83SL38IB' PDF : 88 Pages View PDF
XRT83SL38
OCTAL T1/E1/J1 SH TRANSCEIVER WITH CLOCK RECOVERY AND JITTER ATTENUATOR
PRELIMINARY
REV. P1.1.0
LOCAL ANALOG LOOP-BACK (ALOOP)
With Local Analog Loop-Back activated, the transmit data at TTIP and TRING are looped-back to the analog
input of the receiver. External inputs at RTIP/RRING in this mode are ignored while valid transmit data
continues to be sent to the line. Local Analog Loop-Back exercises most of the functional blocks of the
XRT83SL38 including the jitter attenuator which can be selected in either the transmit or receive paths. Local
Analog Loop-Back is shown in Figure 18.
FIGURE 18. LOCAL ANALOG LOOP-BACK SIGNAL FLOW
TPOS
TNEG
TCLK
RCLK
RPOS
RNEG
Encoder
Decoder
JA
Timing
Tx
Control
Data &
Clock
Rx
Recovery
TTIP
TRING
RTIP
RRING
In this mode, the jitter attenuator (if selected) can be placed in the transmit or receive path.
REMOTE LOOP-BACK (RLOOP)
With Remote Loop-Back activated, receive data after the jitter attenuator (if selected in the receive path) is
looped back to the transmit path using RCLK as transmit timing. In this mode transmit clock and data are
ignored, while RCLK and receive data will continue to be available at their respective output pins. Remote
Loop-Back with jitter attenuator selected in the receive path is shown in Figure 19.
FIGURE 19. REMOTE LOOP-BACK MODE WITH JITTER ATTENUATOR SELECTED IN RECEIVE PATH
TPOS
TNEG
TCLK
Encoder
Timing
Tx
Control
TTIP
TRING
RCLK
Data &
RTIP
RPOS
Decoder
JA
Clock
Rx
Recovery
RRING
RNEG
42
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