trcv012g5 ETC-unknow, trcv012g5 Datasheet - Page 16

• Manufacturer Part Number: trcv012g5
• Description: Trcv012g5 Gbits/s Trcv012g7 Gbits/s Gbits/s Limiting Amplifier, Clock Recovery, Data Demultiplexer
• Manufacturer: ETC-unknow

TRCV012G5 and TRCV012G7
Limiting Amplifier, Clock Recovery, 1:16 Data Demultiplexer
Loss of Signal Detection
The loss of signal circuits are used to detect the conditions of low input signal level or no data transitions at the
input. The LOSDN and LOSAN signals can be processed and/or filtered to meet various system-dependent
requirements on declaring loss of signal.
Digital Loss of Signal (LOSDN)
The LOSDN signal alarm is set when no transitions appear in the data path for more than 2.3 s. The LOSDN sig-
nal will become active before 100 s of no transitions has occurred. When ac coupling the 2.5 Gbits/s data to the
high gain limiting amplifier, in the presence of no significant amplitude data transitions, noise at the limiting ampli-
fier’s input may be amplified and appear to be a data transition. This may change the state of LOSDN.
Analog Loss of Signal (LOSAN, PRG_LOSA)
Low signal levels are detected by the limiting amplifier with an optional user-programmable analog loss of signal
(LOSA) threshold. As shown in Figure 7, applying a voltage to the PRG_LOSA pin will adjust the LOSA trip point.
When the voltage on PRG_LOSA is 0 V, LOSAN will never be active even if the level at the limiting amplifier input
is zero. When the voltage on PRG_LOSA is greater than approximately 1 V and less than 2 V, LOSAN will always
be active regardless of the signal level at the limiting amplifier input. If the voltage of the PRG_LOSA pin exceeds
2 V, the threshold defaults to approximately 12 mVp-p differential. This voltage can be adjusted while monitoring
the BER of the system, and is typically set to activate LOSAN for input levels corresponding to a BER of just above
10
asserted when the input level becomes greater than the LOSA threshold by an amount corresponding to 1 dB (typ-
ical) optical power input. The input resistance of the PRG_LOSA pin is typically 50 k , so a resistor voltage divider
between V
16
–3
. LOSAN will not be asserted unless the alarm condition exists for at least 2.3 s. The LOSAN pin will be de-
CC
and ground may be used to set the PRG_LOSA level if the V
Figure 7. Typical LOSA Threshold vs. PRG_LOSA Voltage vs. Data Pattern
45
40
35
30
25
20
15
10
5
0
0.0
0.1
0.2
0.3
PROGRAM VOLTAGE
0.4
DATA PATTERN
0.5
PRBS
1/1
8/8
0.6
0.7
CC
tolerance and variability is adequate.
0.8
Preliminary Data Sheet
0.9
Lucent Technologies Inc.
1.0
August 2000
5-8070(F)r.2