OBSOLETE

AD9853

–12–

REV. C

NOTES ON BURST TRANSMISSION OPERATION:

1. PACKET LENGTH = NUMBER OF INFORMATION BYTES, K

(K+2T) BYTES WHERE N IS THE NUMBER OF CODEWORDS

3. IF NECESSARY, ZERO FILL THE LAST CODEWORD TO REACH ASSIGNED K DATA BYTES PER CODEWORD

SECONDS AFTER THE

5. PREAMBLE DELAY =

6. DATA RATE MUST BE EXACT SUB-MULTIPLE OF REFERENCE CLOCK.

1

2

(# OF PREAMBLE BITS)

(BIT RATE FREQUENCY)

MINIMUM SPACING BETWEEN BURSTS WITH NO CHANGE IN PROFILE)

NOTE: DATA RATE MUST BE PRECISELY

SYNCHRONIZED WITH RISING EDGE

D1

D2

D3

D4

D5

D6

D7

DN

DON'T CARE

D1

D2

D3

D4

D5

D6

D7 DN

DON'T CARE

DATA PACKET = K BYTES

FEC PARITY

(2T BYTES)

FEC PARITY

(2T BYTES)

DATA PACKET = K BYTES

DATA IN

INTERNAL CODE-

WORD STRUCTURE

AT R-S OUTPUT

FRAME STRUCTURE FOR MULTIPLE CODE WORDS OR CONTINOUS TRANSMISSION:

D1

D2

D3

D4

D5

D6

D7 DN

DON'T CARE

D1

D2

D3 D4

D5

D6

D7 DN

DON'T CARE

DATA PACKET = K BYTES

FEC PARITY

(2T BYTES)

DATA PACKET = K BYTES

FEC PARITY

(2T BYTES)

DATA IN

INPUT DATA PROCESSING:

D1

D59

DN

D60

D61

D62

D63

D64

D65

D1

D2

D2

D3

D4

D5

DATA

PACKET

AND

FEC PARITY

CODEWORD(S)

PREAMBLE

COMPLETE FRAME AS PRESENTED TO MODULATOR ENCODER:

INTERNAL

BIT CLOCK

DATA IN

ENCODER

INPUT

PREAMBLE LENGTH = 96 BITS MAXIMUM

DURING THIS INTERVAL THE DATA IS R-S ENCODED, RANDOMIZED, AND

DELAYED TO SYNCHRONIZE WITH THE END OF THE PREAMBLE DATA.

ONE CODEWORD

ONE CODEWORD

PREAMBLE INSERTION

Figure 26. Data Framing and Processing