MH89790B
Preliminary Information
UI
36.90
20.50
P
E
A
10.0
K
•
8.00
T
O
•
➀
P
E
A
K
2.50
➁
J
I
1.5
T
T
E
R
S
1.00
0.54
(SINUSOIDAL)
0.20
20 Hz
2.4 kHz
1 K
18 kHz
10 K
12 x 10-8
1 Hz
10 Hz
100 Hz
JITTER FREQUENCY
100 K
Figure 13 - Input Jitter Tolerance of MH89790B
➀ - Maximum jitter tolerance of receiver
➁ - Minimum jitter tolerance specified by G.823 and I.431
Bipolar Line Transmitter
The extracted 8 kHz output (E8Ko) is derived from
E2o clock by dividing it by 256. It can be used by an
external phase-locked loop to generate the system
clock and frame pulse that is synchronized to the
network (see Figure 15).
The MH89790B provides two open collector drivers,
OUTA and OUTB. These outputs are suitable for
driving a center-tapped pulse transformer. Figure 29
illustrates how the two outputs combine to create
opposite polarities of the AMI line code. Each output
steers the transformer into producing a pulse of the
opposite polarity.
Clock Extractor
The MH89790B contains a clock extraction circuit
that generates the E2o clock from the received data.
This clock is used to latch received data. The falling
edge of E2o is approximately aligned with the center
of the received data pulse. Alignment between these
signals can be disrupted by jitter and wander on the
received signal.
Maximum tolerance of the
MH89790B to the input jitter is shown in Figure 13
relative to minimum jitter tolerance specified in
G.823 and I.431.
4-202
MITEL [ MITEL NETWORKS CORPORATION ]
