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FALC
56
PEF 2256 H/E
Functional Description T1/J1
User’s Manual
Hardware Description
134
DS1.1, 2003-10-23
RBS1/0 = 00: two frame buffer or 386 bits
Maximum of wander amplitude (peak-to-peak): (1 UI = 648 ns)
System interface clocking rate: modulo 2.048 MHz:
142 UI in channel translation mode 0
78 UI in channel translation mode 1
System interface clocking rate: modulo 1.544 MHz:
Maximum of wander: 140 UI
average delay after performing a slip: 1 frame or 193 bits
RBS1/0 = 01: one frame buffer or 193 bits
System interface clocking rate: modulo 2.048 MHz:
Maximum of wander: 70 UI in channel translation mode 0
Maximum of wander: 50 UI in channel translation mode 1
System interface clocking rate: modulo 1.544 MHz:
Maximum of wander: 74 UI
average delay after performing a slip: 96 bits
RBS1/0 = 10: short buffer or 96 bits
System interface clocking rate: modulo 2.048 MHz:
Maximum of wander: 28 UI in channel translation mode 0; channel translation mode
1 not supported
System interface clocking rate: modulo 1.544 MHz:
Maximum of wander: 38 UI
average delay after performing a slip: 48 bits
RBS1/0 = 11: Bypass of the receive elastic buffer
The buffer functions are:
Clock adaption between system clock (SCLKR) and internally generated route clock
(RCLK).
Compensation of input wander and jitter.
Frame alignment between system frame and receive route frame
Reporting and controlling of slips
Controlled by special signals generated by the receiver, the unipolar bit stream is
converted into bit-parallel, time slot serial data which is circularly written to the elastic
buffer using internally generated Receive Route Clock (RCLK).
Reading of stored data is controlled by the system clock sourced by SCLKR or by the
receive jitter attenuator and the synchronization pulse (SYPR) together with the
programmed offset values for the receive time slot/clock slot counters. After conversion
into a serial data stream, the data is sent out on port RDO. If the receive buffer is
bypassed programming of the time slot offset is disabled and data is clocked off with
RCLK instead of SCLKR.
The 24 received time slots (T1/J1) can be translated into the 32 system time slots (E1)
in two different channel translation modes (FMR1.CTM). Unequipped time slots are set
to FF
H
. See
Table 31
.