Comtech EF Data MD2401 - Manual (Page 31)

MD2401 L-Band Multi Demod Installation and Operation Manual Theory of Operation
MN-MD2401 3–7
Revision 7
3.4.4 Interleaving
The MD2401 allows for interleaving depths of 4 or 8 R-S blocks. This allows burst errors to be
spread over 4 or 8 R-S blocks in order to enhance the error correcting performance of the R-S
Codec.
Figure 3-5. Reed Solomon Decoder Functional Block Diagram
Table 3-1. Reed-Solomon Codes for IDR
Type of Service Data
Rate
(Kbps)
R-S Code
(n, k, t) 1
Bandwidth
Expansion
[ (n/k) -1 ]
Interleaving
Depth
Maximum
2
R-S Codec
Delay (ms)
Small IDR
(with 16/15 O/H)
64
128
256
384
512
768
1024
1536
(126, 112, 7)
(126, 112, 7)
(126, 112, 7)
(126, 112, 7)
(126, 112, 7)
(126, 112, 7)
(126, 112, 7)
(126, 112, 7)
0.125
0.125
0.125
0.125
0.125
0.125
0.125
0.125
4
4
4
4
4
4
4
4
115
58
29
19
15
10
8
5
IDR
(with 96 Kbps O/H)
1544
2048
(225, 205,10)
(219, 201, 9)
0.0976
0.0896
4
4
9
7
n = code length, k = information symbols and t = symbol error correcting
capability.
Design objective
For the MD2401 Demodulator, the IDR Deframing must be supplied externally.