Introduction
DMD2401 LB/ST L-Band Satellite Modem and ODU Driver
1-2
TM075 – Rev. 1.3
Table 1-1. Data Rates
FEC
1/2
2/3
3/4
7/8
BPSK
4800 bps –
1250 Kbps
N/A
7200 bps –
1875 Kbps
8400 bps –
2187.5 Kbps
QPSK
9600 bps –
2500 Kbps
N/A
14400 bps –
3750 Kbps
16800 bps –
4375 Kbps
OQPSK
9600 bps –
2500 Kbps
N/A
14400 bps –
3750 Kbps
16800 bps –
4375 Kbps
8PSK
N/A
Optional
N/A
N/A
The DMD2401 can track and acquire a carrier over a programmable range of ±1 kHz to ±42 kHz.
Acquisition times of less than 10 seconds are typical at data rates of 64 Kbps over a range of
± 25 kHz.
To facilitate link testing, the DMD2401 incorporates built-in ‘2047’ test pattern generators with
BER measurement capability. A user-selectable terrestrial and/or satellite loopback test
capability is also provided.
For applications requiring systems redundancy, multiple DMD2401 modems may be used with
the Radyne RCS11 1:1 Redundancy Switch or the RCS20 M:N (N < 9) Redundancy Switch. A
full range of industry-standard interfaces are available for the DMD2401, DMD2401L, and
DMD2401 IBS/IDR. These include RS-232, V.35, RS-422/-449 and ITU G.703.
1.1 DMD2401 Available Options
A wide range of options are available for the DMD2401 LB/ST which include a low data rate
asynchronous serial overhead channel for remote monitor and control. A brief description of
each follows:
1.1.1 Reed-Solomon Codec
The DMD2401 can be equipped with a Reed-Solomon outer codec with an interleaver as an
optional enhancement for applications requiring Bit Error Rates of 10
-10
. The encoder and
decoder are completely independent and meet IESS-308/-309 Specifications. Once prepped,
this option can be installed in the field by installing four ICs into existing sockets.
Note: Custom Reed-Solomon codes are also available.
1.1.2 Sequential Decoding
The DMD2401 can also be equipped with an optionally installed sequential decoder. The
DMD2401 must be prepped for this option in the factory. Once prepped, the option can be
added by installing an IC into an existing socket. Sequential Encoding/Decoding can operate
with 1/2, 3/4, and 7/8 Rates up to data rates of 4.375 Mbps.
1.1.3 Asynchronous Overhead Channel
The DMD2401 can be equipped with optional asynchronous overhead channel capability. The
option can be added in the field by installing a single interface PC board. The overhead channel
is proportional to the data rate (Baud Rate is approximately 1/2000 of the Data Rate for Standard
IBS and up to a maximum of 19.2 Kbaud for IBS Async).