PEB22554 SIEMENS [Siemens Semiconductor Group], PEB22554 Datasheet - Page 38

• Manufacturer Part Number: PEB22554
• Description: ICs for Communications
• Manufacturer: SIEMENS [Siemens Semiconductor Group]

When using the optical interface with NRZ coding, the decoder is by-passed and no code
violations will be detected.
The signal at the ternary interface is received at both ends of a transformer.
The operating modes 75 or 120
selection does not require changing transformers.
Figure 11
Receiver Configuration
Recommended Receiver Configuration Values
Parameter
R
t
Loss of Signal Detection
There are different definitions for detecting Loss of Signal (LOS) alarms in the ITU-T
G.775 and ETS 300233. The QuadFALC covers all these standards. The LOS indication
is performed by generating an interrupt (if not masked) and activating a status bit.
Additionally a LOS status change interrupt is programmable via register IPC.SCI.
• Detection:
Semiconductor Group
2
1
:
An alarm will be generated if the incoming data stream has no pulses (no transitions)
for a certain number (N) of consecutive pulse periods. “No pulse” in the digital receive
interface means a logical zero on pins RDIP/RDIN/ROID. A pulse with an amplitude
less than Q dB below nominal is the criteria for “no pulse” in the analog receive
interface (LIM1.DRS=0). The receive signal level Q is programmable via three control
bits LIM1.RIL2-0 in a range of about 900 to 50 mV differential voltage between pins
RL1/2. The number N can be set via an 8 bit register PCD. The contents of the PCD
register will be multiplied by 16, which results in the number of pulse periods or better,
the time which has to suspend until the alarm has to be detected. The range results
( 1 %) [ ]
t
1
Line
t
2
t
1
are selectable by switching resistors in parallel. This
38
R
2
120
100-120
1 : 1
Characteristic Impedance [ ]
RL1
RL2
FALC
Functional Description E1
R
ITS10967
75
75
1 : 1
PEB 22554
09.98