Paradise Datacom P300 Series Installation & Operating Handbook page 70

For FEC the FEC rate selection screen is as follows:
Change, Tx/Rx, Mod/Demod, FEC Rate Menu (Turbo)
The Turbo FEC code rate may be selected from the scroll list of preset rates displayed on the screen.
pressing YES will accept the current FEC rate and return to the Change, Tx, Modulator menu. This list
can contain up to 31 different rates, but currently only the following are defined:
Screen Description
"0.3125 Industry de-facto 5/16 rate"
"0.477 Industry de-facto 21/44 rate"
"0.493 Paradise 1/2 rate"
"0.666 Paradise 2/3 rate"
"0.750 Industry de-facto 3/4 rate"
"0.789 Paradise 3/4 rate"
"0.875 Paradise 7/8 rate" **
(Low Latency)
* Note on processing delay. Use the data rate before the FEC to determine the delay in milliseconds from
the delay in bits. For example at 1Mbps using Rate 0.789 Turbo FEC, the FEC delay is (6498/1000000)
seconds, which is 6.5ms.
** Note on Low Latency 7/8 Rate Turbo: As Turbo FEC schemes go this is a relatively poor performer.
BUT it does provide about a 1dB performance improvement over 7/8 rate Viterbi, and for links where the
transponder space is fixed to accommodate a 7/8 Viterbi coded link, switching from Viterbi to Turbo will
give a useable 1dB improvement. It also provides significantly lower latency than subsequent Turbo
schemes (which offer a better 7/8 rate performance at the cost of significant latency). If you`re stuck with a
channel that can only accommodate 7/8 Rate FEC, then this will give you an extra dB over using Viterbi.
P300H P300 Series Modem Installation and Operating Handbook
Select Turbo Mode/Code rate, then (YES)
[0.750 Industry de-facto 3/4 rate]
Exact
code rate
0.3125
21/44
2028/4116
2499/3748
0.750
3249/4116
0.875
Delay Modulation Schemes from
(bits) *
BPSK QPSK
2662 V3.57
4056 V3.57
4056 V3.40
4998 V3.57 V3.57
4446 V3.40
6498 V3.40
450 V3.40
(yes 450)
OQPSK 8PSK
n/a
n/a
n/a
n/a
V3.57
n/a
n/a
n/a
Page 70