XRT83L30 Datasheet, PDF (23/78 Pages) Exar Corporation – SINGLE-CHANNEL T1/E1/J1 LH/SH TRANSCEIVER WITH CLOCK RECOVERY AND JITTER ATTENUATOR

áç
XRT83L30
ONE-CHANNEL T1/E1/J1 LH/SH TRANSCEIVER WITH CLOCK RECOVERY AND JITTER ATTENUATOR
PRELIMINARY
REV. P1.3.0
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.
FIGURE 7. SIMPLIFIED DIAGRAM OF -29dB T1/E1 GAIN MODE AND RLOS CONDITION
+3dB
-9dB
Normalized up to +29dB Max
Clear LOS
Declare LOS
+3dB
-9dB
Declare LOS
Clear LOS
Normalized up to +29dB Max
Setting the Receiver Input to -36dB T1/E1 Long Haul Mode
By setting the receiver input to -36dB T1/E1 long haul mode, the equalizer will detect the incoming amplitude
and make adjustments by adding gain up to a maximum of +36dB normalizing the T1 input signal. This setting
refers to cable loss (frequency), not flat loss (resistive). Once the T1/E1 input signal has been normalized to
0dB by adding the maximum gain (+36dB), the receiver will declare RLOS if the signal is attenuated by an
additional -9dB. The total cable loss at RLOS declaration is typically -45dB (-36dB + -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 cable attenuation of -42dB. See Figure 8 for a simplified diagram.
FIGURE 8. SIMPLIFIED DIAGRAM OF -36dB T1/E1 LONG HAUL MODE AND RLOS CONDITION
+3dB
-9dB
Normalized up to +36dB Max
Clear LOS
Declare LOS
+3dB
-9dB
Declare LOS
Clear LOS
Normalized up to +36dB Max
E1 Extended RLOS
E1: Setting the Receiver Input to Extended RLOS
By setting the receiver input to extended RLOS, the equalizer will detect the incoming amplitude and make
adjustments by adding gain up to a maximum of +43dB normalizing the E1 input signal. This setting refers to
cable loss (frequency), not flat loss (resistive). Once the E1 input signal has been normalized to 0dB by adding
the maximum gain (+43dB), the receiver will declare RLOS if the signal is attenuated by an additional -9dB.
20