Comtech-ef-data SDM-2020 Instrukcja Użytkownika Pobierz pdf (Strona 32)

SDM-2020 Satellite Demodulator Revision 4

Introduction MN/SDM2020D.IOM

1–6

1.4.2 Transmit/Receive Data

The data format for the transmit (TX) and receive (RX) data interfaces are the same.

There are three general modes of operation:

• None (187)

• 188

• 204

When None (187) mode is selected,

no frame structure is expected, while the 188 and 204

modes will synchronize to standard MPEG-2 transport frames. Other supported data

formats are referenced in the appropriate section of this appendix, but the data from other

frame formats is extracted and converted to one of the three modes of operation.

Figure 1-3 and Figure 1-4 depict the 204-byte packetization for byte parallel and byte

serial formats, showing all possible data fields and timing signal relationships. The 188

byte and no framing formats are subsets of the 204 byte format.

1 Byte Sync 1 Byte Sync

187 Bytes Payload

SYNC

DATA

DVALID

CLOCK

SYNC

1187 116

16 RS Bytes

Figure 1-3. 204 Byte Parallel Format

0100 1011

Bits

ync

Bits Payload

SYNC

DATA

DVALID

CLOCK

0100 1011

Bits

ync

128

Bits R

Figure 1-4. 204 Byte Serial Format

1 2 ... 27 28 29 30 31 32 33 34 35 36 37 ... 233 234

Brak uwag

Comtech-ef-data SDM-2020 Instrukcja Użytkownika Strona 32