MT8950AC Ver la hoja de datos (PDF) - Mitel Networks
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MT8950AC Datasheet PDF : 16 Pages
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ISO-CMOS MT8950
125 µs
Internal
Clock
0 1 2 3 4 5 6 7 8 9 10 • • •
b7-1
#1
1
1
2
b4b3b2b1b0
22 23 24 25 26 27 28 29 30 31 0
b70
b4b3b2b1b0=11111
1
1
Frame Type
b6 b5
11
11
1
3
1
4
b4b3b2b1b0
b4b3b2b1b0
1
5
1
6
1
7
b1b0
b4b3b2b1b0
b4b3b2b1b0
b4b3b2
0
11
0
10
1
10
1
01
1
00
01234
01234567
Figure 3 - TEM Coding Scheme
(Note: Waveforms shown are bipolar RZ equivalent of separate RZ/NRZ inputs)
#
Frame
Description
Level†
b7
Frame Type
b6 b5
First Transition
b4 b3 b2 b1 b0
Notes
1 No Pulse
1/0
11
11111
2 2 Data Pulses (T=52 µs)
1/0
11
XXXXX
X X X X X ≤ 10001 (17)
3 3 Data Pulses (T=52 µs)
1/0
11
X X X XX
X X X X X ≤ 00100 (4)
4 1 Data Pulse
1/0
10
XXXXX
X X X X X = 0 to 31
5 Violation Pulse
1/0
10
XXXXX
X X X X X = 0 to 31
6 2 Data Pulses (T=104 µs)
1/0
(Timeslot 4 to 31)
01
XXXXX
X X X X X > 00011 (3)
7 2 Data Pulses (T=104 µs)
1/0
(Timeslot 0 to 3)
00
YYYXX
XX = 0 to 3
YYY = 0 to 7
Table 2. TEM Coding Summary
† Note: The Level bit (b7) indicates the level (HIGH or LOW) of the input data in timeslot 31 of the current frame.
of seven frames types are possible as shown in
Figure 3. In frame type 7, the first five bits (b0 to b4)
are used to represent two transitions instead of the
normal first transition. Note that the data transitions
in Figure 3 are shown as a three level signal. A
positive transition indicates the beginning of one or
more continuous MARKs and a negative transition
indicates the beginning of one or more continuous
SPACEs.
The decoder stage regenerates the original data
from the 8 bit TEM word. The absolute values of the
data signal in the present and previous frames as
given by b7(n) and b7(n-1) are EX-ORed and the
result in combination with the remaining bits of the
TEM word is used to reproduce the original data with
an accuracy of ± 3.906µs (see Table 2). Due to the
data speed restriction above 8 kbps, the second and
third transitions (if any) will be reproduced at
6-7
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