
PEB 2255
FALC-LH V1.3
Functional Description T1/J1
Data Sheet
111
2000-07
Generation of control signals to synchronize the CRC checker and the receive elastic
buffer.
If programmed and applicable to the selected multiframe format, CRC checking of the
incoming data stream is done by generating check bits for a CRC multiframe according
to the CRC 6 procedure (refer to IT
U
-T G.70
4
). These bits are compared with those
check bits that are received during the next CRC multiframe. If there is at least one
mismatch, the CRC error counter (16 bit) is incremented.
5.1.11
Receive Elastic Buffer (T1/J1)
The received bit stream is stored in the receive elastic buffer. The memory is organized
as a two-frame elastic buffer with a maximum size of
48
×
8
bit. The size of the elastic
buffer can be configured independently for the receive and transmit direction.
Programming of the receive buffer size is done by SIC1.RBS1/0 :
RBS1/0
=
00 : two frame buffer or 3
84
bits
Maximum of wander amplitude (peak-to-peak): (1
U
I
=
6
48
ns )
System interface clocking rate:
8
.1
9
2 MHz:
1
4
2
U
I in channel translation mode 0
7
8 U
I in channel translation mode 1
System interface clocking rate: 1.5
44
MHz:
max. wander: 126
U
I
average delay after performing a slip: 1 frame or 1
9
3 bits
RBS1/0
=
01 : one frame buffer or 1
9
3 bits
System interface clocking rate:
8
.1
9
2 MHz:
Max. wander :
8
0
U
I in channel translation mode 0
Max. wander : 50
U
I in channel translation mode 1
System interface clocking rate: 1.5
44
MHz:
max. wander: 7
4 U
I
average delay after performing a slip:
9
6 bits
RBS1/0
=
10 : short buffer or
9
6 bits :
System interface clocking rate:
8
.1
9
2 MHz:
Max. wander : 2
8 U
I in channel translation mode 0
;
channel translation mode 1 not
supported
System interface clocking rate: 1.5
44
MHz:
max. wander: 3
8 U
I
average delay after performing a slip:
48
bits
RBS1/0
=
11 : Bypass of the receive elastic buffer
The functions of the receive elastic buffer are:
Clock adaption between system clock (SCL
K
R) and internally generated route clock
(RCL
K
).
Compensation of input wander and jitter.