Paradise P300 For Turbo FEC the FEC rate selection screen is as follows, Modulation Schemes from

For Turbo FEC the FEC rate selection screen is as follows:

Select Turbo Mode/Code rate, then (YES) [0.750 Industry de-facto 3/4 rate]

Change, Tx/Rx, Mod/Demod, FEC Rate Menu (Turbo)89

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	Exact	Delay
	code rate	(bits) *
“0.3125 Industry de-facto 5/16 rate”	0.3125	2662
“0.477 Industry de-facto 21/44 rate”	21/44	4056
"0.493 Paradise ½ rate"	2028/4116	4056
“0.666 Paradise 2/3 rate	2499/3748	4998
"0.750 Industry de-facto 3/4 rate"	0.750	4446
"0.789 Paradise 3/4 rate"	3249/4116	6498
"0.875 Paradise 7/8 rate" **	0.875	450
(Low Latency)		(yes 450)

Modulation Schemes from

BPSK	QPSK	OQPSK	8PSK
	V3.57		n/a
	V3.57		n/a
	V3.40		n/a
V3.57	V3.57	V3.57	n/a
	V3.40		n/a
	V3.40		n/a
	V3.40		n/a

*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 Page 67