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SLM-5650 Satellite Modem Revision 2
Introduction MN/SLM5650.IOM
1–10
1.8.1 Performance
1.8.2 Acquisition and Timing Performance Requirements
Note: The following reference Eb/No is defined as the required Eb/No corresponding to a
BER of IE-3 with R-S FEC not enabled.
Table 1-2. Acquisition and Timing Performance Requirements
Parameter Specification
Initial Acquisition
The modem achieves initial acquisition within the times as specified within ± 30 kHz
at the reference Eb/No
• For baseband data rates between 64 kbps and ≤ 128 kbps, the maximum initial
acquisition time is 500 seconds.
• For Baseband data rates between 128kbps and ≤ 1544 kbps, the maximum
initial acquisition time is 30 seconds.
• For baseband data rates > 1544 kbps, the maximum initial acquisition time is
1.5 seconds.
Reacquisition Reacquisition is achieved, as follows, after a period of up to 15 minutes of the
absence of signal when the carrier returns to within 500 Hz of its original frequency.
• For baseband data rates between 64 kbps and 128 kbps, the maximum
reacquisition time shall be 45 seconds.
• For baseband data rates between 128 kbps and 1544 kbps, the maximum
reacquisition time shall be 20 seconds.
• For baseband data rates greater than 1544 kbps, the maximum reacquisition
time shall be 1 second.
BCI With Tx and Rx random data, the mean time to loss of BCI due to falsely adding or
deleting bits is at least 3 days at the reference E
b
/N
0
. In addition, the modem
maintains BCI over 50 consecutive bits of all ones or zeros, which occur no more than
once in 10,000 bits, without employing data scrambling.
System Retention Synchronization and BCI are maintained for all E
b
/N
0
above the reference E
b
/N
0
(BPSK/QPSK/OQPSK/8-PSK) for signal loss of up to 50 modulation symbol
periods, with a probability of at least 90 percent.
Receive Timing Jitter
The Rx output clock peak timing jitter cannot exceed ± 5 percent at the reference
E
b
/N
0
when the modulated signal meets the modulation timing jitter requirement.
Doppler The modem meets the requirements with a Doppler shift, rate of change, and
acceleration for satellite inclination up to ± 7° as presented in Table A-6, and an
additional 0.5 dB added to the reference E
b
/N
0
.