P300H
P300 Modem Installation and Operating Handbook
Page 25
External Transmit Inhibit
By external contact closure or by TTL signal applied to rear panel
connector. Hardware function overrides processor control
Demodulator Specifications
IF Input Range
-45dBm nominal, ±15dB (desired carrier)
Maximum Composite Signal
30 dB above level of desired input up to a maximum of 0 dBm
Frequency Acquisition
Selectable from ± 1 kHz to ± 32 kHz
Range
Acquisition Threshold
< 5 dB Eb/No
Acquisition Time
@ 9.6 kbps < 3 seconds at 6 dB Eb/No
(rate ½ FEC)
@ 64 kbps < 2 seconds at 6 dB Eb/No
@ 2048 kbps < 500 ms at 6 dB Eb/No
Clock Tracking Range
± 100 ppm min
Receive Filtering
6th order Butterworth, group delay equalised (INTELSAT IESS compliant)
BER Performance
In all cases met in the presence of two adjacent carriers each 10 dB
higher than the desired carrier, with V.35 scrambling
These figures meet or exceed the relevant IESS performance
specifications.
Rate ½
Rate ¾
Rate
I
I
Rate
E
E
Viterbi
(all rates)
1 x 10
4.7 dB
6.1 dB
7.1 dB
-4
1 x 10
7.2 dB
8.8 dB
9.5 dB
-8
Sequential
(64kbps)
1 x 10
4.3 dB
5.4 dB
6.4 dB
-4
1 x 10
6.4 dB
7.3 dB
8.6 dB
-8
Sequential
(2048kbps)
1 x 10
5.6 dB
6.1 dB
6.9 dB
-4
1 x 10
7.5 dB
8.1 dB
8.4 dB
-8
Turbo (TPC, QPSK)
(all rates)
1 x 10
2.6dB
3.5dB
6.0dB
-4
1 x 10
3.7dB
4.5dB
8.3dB
-8
8PSK/TCM
(all rates)
1 x 10
6.3 dB
-3
1 x 10
10.4 dB
-8
8PSK/TCM + Reed-
Solomon
(all rates)
1 x 10
6.1 dB
-4
1 x 10
7.3 dB
-10
BER performance with
concatenated RS
BER improvement depends on n and k values chosen, but a typical
increase in coding gain of 3 dB is possible over basic Viterbi mode.