Information Manual
DSP1611/17/18/27/28/29 DIGITAL SIGNAL PROCESSOR
April 1998
Error Correction Coprocessor (DSP1618/28 Only)
Lucent Technologies Inc.
DRAFT COPY
14-7
14.4 Operation of the ECCP
To operate the ECCP, the user first programs its mode of operation by setting the control register (ECON), setting
the traceback length register (TBLR), and appropriately initializing the present state accumulated costs. The com-
plete Viterbi decoding operation is achieved by the following steps: recursively loading the received symbols into
the ECCP; executing the ECCP with an UpdateMLSE, an UpdateConv, or a TraceBack instruction; and, finally,
unloading the decoded symbol from the ECCP. The operation of the ECCP is captured in the signal flow diagram in
.
5-4502
Figure 14-3. ECCP Operation Sequence
DSP PROGRAMS ECCP
DSP LOADS CHANNEL/GENERATING
POLYNOMIALS INTO THE ECCP
DSP LOADS RECEIVED
SYMBOLS INTO THE ECCP
DSP EXECUTES
UPDATE INSTRUCTION
NEW
ADAPTED
CHANNEL
TL = TBLR
FETCH MINIMUM COST INDEX
CALCULATE
REVERSED PATH
TL = TL – 1
IS
TL = 0?
IS
TRACEBACK
INSTR.
?
?
DECREMENT
TBLR BY ONE
OUTPUT
DECODED SYMBOL
VITERBI
DECODING
COMPLETE
ALL
SYMBOLS
DECODED
?
NO
YES
YES
NO
NO
NO
YES
SET K = 0
CALCULATE BRANCH METRIC
CALCULATE ACCUMULATED COST
FOR STATE TRANSITIONS TO K
FOR BOTH STATE TRANSITIONS TO K
SELECT MINIMUM ACCUMULATED
COST AS SURVIVOR PATH
UPDATE MINIMUM COST INDEX
STORE SURVIVOR PATH
INCREMENT
K BY ONE
IS
K < 2
(C – 1)
– 1
?
YES
NO
YES
Содержание DSP1611
Страница 18: ...Chapter 1 Introduction...
Страница 27: ...Chapter 2 Hardware Architecture...
Страница 52: ...Chapter 3 Software Architecture...
Страница 116: ...Chapter 4 Instruction Set...
Страница 154: ...Chapter 5 Core Architecture...
Страница 176: ...Chapter 6 External Memory Interface...
Страница 208: ...Chapter 7 Serial I O...
Страница 237: ...Chapter 8 Parallel I O DSP1617 Only...
Страница 261: ...Chapter 9 Parallel Host Interface PHIF DSP1611 18 27 28 29 Only...
Страница 275: ...Chapter 10 Bit I O Unit...
Страница 284: ...Chapter 11 JTAG Test Access Port...
Страница 306: ...Chapter 12 Timer...
Страница 313: ...Chapter 13 Bit Manipulation Unit...
Страница 325: ...Chapter 14 Error Correction Coprocessor DSP1618 28 Only...
Страница 350: ...Chapter 15 Interface Guide...
Страница 367: ...Appendix A Instruction Encoding...
Страница 379: ...Appendix B Instruction Set Summary...
Страница 381: ...aD extractz aS IM16 B 52 aD insert aS arM B 53 aD insert aS IM16 B 54 aD aS aaT B 55...
Страница 437: ...Index...