S-2
Specifications
PDH MUX/DEMUX
ANT-20/ANT-20E
The following bits can be dynamically programmed:
Bits S
a
4 thruogh S
a
8 can be selected and each loaded with a freely programmable pattern 8 bits
in length. This permits transmission of S
a
sequences.
For PCM 30 / PCM 30 CRC systems, frame 0 or 1 in timeslot 16 can be loaded with a freely
programmable 8 bit word. Frames 2 through 15 can be loaded with a further freely
programmable 8 bit word.
1.2.2
CRC checksum (PCM 30 CRC / PCM 31 CRC)
The ANT-20 calculates the CRC checksum for the measured channel and the filler channels as
per ITU-T recommendation G.704 and inserts the result bits at the appropriate position in the
pulse frame.
1.3
Justification as per ITU-T G.742 and G.751
The bit rates in the upper and subordinate systems are in a fixed relationship to each other.
Justification is at a nominal rate (offset of upper and subordinate systems is identical).
Exception: Insertion of external signals.
1.3.1
PDH tributary offset
Static offset for the PDH tributary bit rates during insertion into the SDH container.
The offset is an average value. The actual offset at any given time may be above or below this
value.
PCM 30/ PCM 30 CRC (G.704). . . . . . . . . . . . . . NFAS bit nos. 4 through 8 (S
a
4 through S
a
8)
Upper system
bit rate in kbit/s
ITU-T
Justification ratio
Nominal justification rate
in kbit/s
8448
G.742
0.42424
4.226
34368
G.751
0.43575
9.750
139264
G.751
0.41912
9.934
Table S-2
Justification
Offset . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
±
100 ppm
for all bit rates, relative to SDH container
Step width . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 ppm
