XRT83SL34 datasheet(24/80 Pages) EXAR

24 / 80 page

XRT83SL34

QUAD T1/E1/J1 SH TRANSCEIVER WITH CLOCK RECOVERY AND JITTER ATTENUATOR

REV. P1.0.8

PRELIMINARY

typically -38dB (-29dB + -9dB). A 3dB hysteresis was designed so that transients will not trigger the RLOS to

clear. Therefore, the RLOS will typically clear at a total flat loss of -35dB. See Figure 7 for a simplified diagram.

RECEIVE HDB3/B8ZS DECODER

The Decoder function is available in both Hardware and Host modes on a per channel basis by controlling the

TNEG_n/CODES_n pin or the CODES_n interface bit. The decoder function is only active in single-rail Mode.

When selected, receive data in this mode will be decoded according to HDB3 rules for E1 and B8ZS for T1

systems. Bipolar violations that do not conform to the coding scheme will be reported as Line Code Violation at

the RNEG_n/LCV_n pin of each channel. The length of the LCV pulse is one RCLK cycle for each code

violation. In E1mode only, an excessive number of zeros in the receive data stream is also reported as an error

at the same output pin. If AMI decoding is selected in single rail mode, every bipolar violation in the receive

data stream will be reported as an error at the RNEG_n/LCV_n pin.

RECOVERED CLOCK (RCLK) SAMPLING EDGE

This feature is available in both Hardware and Host modes on a global basis. In Host mode, the sampling

edge of RCLK output can be changed through the interface control bit RCLKE. If a “1” is written in the RCLKE

interface bit, receive data output at RPOS_n/RDATA_n and RNEG_n/LCV_n are updated on the falling edge of

RCLK for all eight channels. Writing a “0” to the RCLKE register, updates the receive data on the rising edge of

RCLK. In Hardware mode the same feature is available under the control of the RCLKE pin.

FIGURE 7. SIMPLIFIED DIAGRAM OF -29dB T1/E1 GAIN MODE AND RLOS CONDITION

FIGURE 8. RECEIVE CLOCK AND OUTPUT DATA TIMING

Norm alized up to +29dB Max

Declare LOS

Clear LOS

-9dB

+3dB

Clear LOS

Declare LOS

+3dB

-9dB

RCLK

RPOS

RNEG

XRT83SL34 Datasheet(PDF) 24 Page - Exar Corporation