16 psk ppt

Fall 2001 ENZO PATERNOENZO PATERNO 1

ELECTRONICELECTRONIC

COMMUNICATIONSCOMMUNICATIONS

SYSTEMSSYSTEMS

PART 12-4

Fall 2001 ENZO PATERNOENZO PATERNO 2

DIGITALCOMMUNICATIONS

Fall 2001 ENZO PATERNOENZO PATERNO 3

PHASE SHIFTKEYING

Fall 2001 ENZO PATERNOENZO PATERNO 4

EIGHT PHASE SHIFT KEYING (8-PSK)EIGHT PHASE SHIFT KEYING (8-PSK)

• M-M-ARY ARY CODING SCHEME WITH M = 8, N = 3CODING SCHEME WITH M = 8, N = 3• EIGHT OUTPUT PHASES ARE POSSIBLE EIGHT OUTPUT PHASES ARE POSSIBLE • THE INPUT BINARY DATA IS COMBINED INTOTHE INPUT BINARY DATA IS COMBINED INTO GROUPS OF 3 (N = 3) BITS CALLED GROUPS OF 3 (N = 3) BITS CALLED TRIBITSTRIBITS

• TRIBIT TRIBIT CODE: 000 = PHASE 1, 001 = PHASE 2, 010 = PHASE 3CODE: 000 = PHASE 1, 001 = PHASE 2, 010 = PHASE 3 011 = PHASE 4, 100 = PHASE 5, 101 = PHASE 6011 = PHASE 4, 100 = PHASE 5, 101 = PHASE 6

110 = PHASE 7, 111 = PHASE 8110 = PHASE 7, 111 = PHASE 8

• 1 SYMBOL = 1 PHASE = 3 BITS1 SYMBOL = 1 PHASE = 3 BITS

BAUD RATEBAUD RATE = 1/3 = 1/3 BIT RATEBIT RATE((SYMBOLS PER SECSYMBOLS PER SEC)) ((BITS PER SECBITS PER SEC))

Fall 2001 ENZO PATERNOENZO PATERNO 5

8-PSK MODULATOR8-PSK MODULATOR

BIT SPLITTERBIT SPLITTER(SERIAL TO(SERIAL TOPARALLEL)PARALLEL)

3

bf

2-input DAC2-input DAC

2-input DAC2-input DAC

PULSE AMPLITUDE MODULATEDPULSE AMPLITUDE MODULATEDSIGNAL (4 LEVELS)SIGNAL (4 LEVELS)

PULSE AMPLITUDE MODULATEDPULSE AMPLITUDE MODULATEDSIGNAL (4 LEVELS)SIGNAL (4 LEVELS)

Fall 2001 ENZO PATERNOENZO PATERNO 6

8-PSK MODULATOR8-PSK MODULATOR

I CHANNELI CHANNELTRUTH TABLETRUTH TABLE

Q CHANNELQ CHANNELTRUTH TABLETRUTH TABLE

• I, Q DETERMINE POLARITY; 0 = - , 1 = +I, Q DETERMINE POLARITY; 0 = - , 1 = +

• DETERMINE THE LEVEL; 1 = 1.307v, 0 = 0.541vDETERMINE THE LEVEL; 1 = 1.307v, 0 = 0.541v

• 2 LEVELS + 2 POLARITIES GIVE 4 CONDITIONS 2 LEVELS + 2 POLARITIES GIVE 4 CONDITIONS

CC,

PAM SIGNALPAM SIGNAL(4 LEVELS)(4 LEVELS)

Fall 2001 ENZO PATERNOENZO PATERNO 7

8-PSK GENERATION: TRIBIT = 0008-PSK GENERATION: TRIBIT = 000

000000

00

0000

11

- 0.541v- 0.541v

- 1.307v- 1.307v

NOTE: BECAUSE NOT THE SAME, I-CHANNELNOTE: BECAUSE NOT THE SAME, I-CHANNELPAM WILL NEVER EQUAL Q-CHANNEL PAMPAM WILL NEVER EQUAL Q-CHANNEL PAM

CC,

)2sin(541.0 tfc

)2cos(307.1 tfc

Fall 2001 ENZO PATERNOENZO PATERNO 8

8-PSK GENERATION: OUTPUT PHASES8-PSK GENERATION: OUTPUT PHASES

TRIBIT CODE: 000TRIBIT CODE: 000

)5.112sin(41.1)cos(307.1)sin(541.0 ttt ccc

PROOF:PROOF: YXYXYX sincoscossin)sin(

)2cos(307.1)2sin(541.0

)2cos()924(.41.1)2sin()383.(41.1

)5.112sin()2cos(41.1)5.112cos()2sin(41.1

)5.1122sin(41.1

tftf

tftf

tftf

tf

cc

cc

cc

c

0 0 0 ==> -112.5 degrees0 0 0 ==> -112.5 degrees

Fall 2001 ENZO PATERNOENZO PATERNO 9

8-PSK GENERATION: OUTPUT PHASES8-PSK GENERATION: OUTPUT PHASES

TRIBIT CODE BETWEENTRIBIT CODE BETWEENADJACENT PHASESADJACENT PHASESFOLLOWS THEFOLLOWS THEGRAYCODEGRAYCODE(RESULTS IN ONLY (RESULTS IN ONLY A SINGLE BIT ERRORA SINGLE BIT ERRORFOR UNDESIRED PHASEFOR UNDESIRED PHASESHIFTS)SHIFTS)

Fall 2001 ENZO PATERNOENZO PATERNO 10

8-PSK GENERATION: OUTPUT PHASES8-PSK GENERATION: OUTPUT PHASES

• FOR QPSK: 4 OUTPUT PHASES (+45, +135, -45, -135)FOR QPSK: 4 OUTPUT PHASES (+45, +135, -45, -135) THE SEPARATION BETWEEN ADJACENTTHE SEPARATION BETWEEN ADJACENT PHASORS IS 360/4 = 90 degrees.PHASORS IS 360/4 = 90 degrees.

• FOR 8-PSK: 8 OUTPUT PHASES. THE SEPARATIONFOR 8-PSK: 8 OUTPUT PHASES. THE SEPARATION BETWEEN PHASES IS 360/8 = 45 degrees. A 8-PSK SIGNALBETWEEN PHASES IS 360/8 = 45 degrees. A 8-PSK SIGNAL CAN UNDERGO A +/- 22.5 degrees PHASE SHIFT DURINGCAN UNDERGO A +/- 22.5 degrees PHASE SHIFT DURING TRANSMISSION AND STILL RETAIN ITS INTEGRITY.TRANSMISSION AND STILL RETAIN ITS INTEGRITY.

Fall 2001 ENZO PATERNOENZO PATERNO 11

8-PSK GENERATION: OUTPUT PHASES8-PSK GENERATION: OUTPUT PHASES

• FOR 8-PSK, EACH PHASOR IS EQUAL IN MAGNITUDEFOR 8-PSK, EACH PHASOR IS EQUAL IN MAGNITUDE (1.41v)(1.41v)

• THE TRIBIT CODE INFORMATION IS CONTAINEDTHE TRIBIT CODE INFORMATION IS CONTAINED ONLY IN THE PHASE OF THE SIGNALONLY IN THE PHASE OF THE SIGNAL

Fall 2001 ENZO PATERNOENZO PATERNO 12

8-PSK GENERATION: OUTPUT PHASES8-PSK GENERATION: OUTPUT PHASES

OUTPUT PHASE VERSUS TIME FOR 8-PSK MODULATOROUTPUT PHASE VERSUS TIME FOR 8-PSK MODULATOR

Fall 2001 ENZO PATERNOENZO PATERNO 13

tbtb tbtb

22

1 b

br

f

tf

BIT RATE BEFORE SPLITTER = BIT RATE BEFORE SPLITTER = bb

ft

1

REPETITION RATE BEFORE SPLITTERREPETITION RATE BEFORE SPLITTER

BIT RATE AFTER SPLITTER = BIT RATE AFTER SPLITTER = 33

1 b

b

f

t

REPETITION RATE AFTER SPLITTERREPETITION RATE AFTER SPLITTER 6)3(2

1 b

br

f

tf

IIQQ

tbtb tbtb

SERIALSERIAL

PARALLELPARALLELI or Q or CI or Q or C

(SERIAL)(SERIAL)

(SERIAL)(SERIAL)

(PARALLEL)(PARALLEL)

(PARALLEL)(PARALLEL)

CCBANDWITH CONSIDERATION OF 8-PSKBANDWITH CONSIDERATION OF 8-PSK

Fall 2001 ENZO PATERNOENZO PATERNO 14

BANDWITH CONSIDERATION OF 8-PSKBANDWITH CONSIDERATION OF 8-PSK

3

bf

6

brf

f

Fall 2001 ENZO PATERNOENZO PATERNO 15

8-PSK GENERATION: BAUD RATE8-PSK GENERATION: BAUD RATE

• FOR 8-PSK, THERE IS ONE CHANGE IN PHASE AT THEFOR 8-PSK, THERE IS ONE CHANGE IN PHASE AT THE OUTPUT FOR EVERY THREE DATA INPUT BITS.OUTPUT FOR EVERY THREE DATA INPUT BITS. (A GROUP OF THREE BITS = 1 PHASE = 1 SYMBOL)(A GROUP OF THREE BITS = 1 PHASE = 1 SYMBOL)

THUS, THE BAUD RATE = 1/3 BIT RATE = THUS, THE BAUD RATE = 1/3 BIT RATE = 3

bf

Fall 2001 ENZO PATERNOENZO PATERNO 16

BANDWITH CONSIDERATION OF 8-PSKBANDWITH CONSIDERATION OF 8-PSK

)2sin()2sin()(8 tfXtftv rcpsk cf REFERENCE CARRIER FREQUENCYREFERENCE CARRIER FREQUENCY

REPETITION RATE (FUNDAMENTALREPETITION RATE (FUNDAMENTALFREQUENCY OF I or Q or C CHANNEL BITS)FREQUENCY OF I or Q or C CHANNEL BITS)IT IS 1/6 THE BIT RATEIT IS 1/6 THE BIT RATE6

brf

f

)cos(2

1)cos(

2

1))(sin(sin YXYXYX

tffX

tffX

tv rcrcpsk )(2cos2

)(2cos2

)(

LOWER SIDE FREQUENCYLOWER SIDE FREQUENCY UPPER SIDE FREQUENCYUPPER SIDE FREQUENCY

X = +/- 1.307 OR +/- 0.541X = +/- 1.307 OR +/- 0.541

Fall 2001 ENZO PATERNOENZO PATERNO 17

rc ff rc ff cf

B

3622

bbr

fffB

BANDWITH CONSIDERATION OF 8-PSKBANDWITH CONSIDERATION OF 8-PSK

LSBLSB USBUSB

LSFLSF USFUSF

6

brf

f 6

brf

f

DSB-SC MODULATIONDSB-SC MODULATION

Fall 2001 ENZO PATERNOENZO PATERNO 18

EXAMPLEEXAMPLE

FOR AN 8-PSK MODULATOR WITH A CARRIERFOR AN 8-PSK MODULATOR WITH A CARRIERFREQUENCY OF 70 MHz AND AN INPUT BIT RATE OFFREQUENCY OF 70 MHz AND AN INPUT BIT RATE OF10 Mbps, DETERMINE a) THE LSF b) USF c) B d) BAUD RATE10 Mbps, DETERMINE a) THE LSF b) USF c) B d) BAUD RATE

MHzfc 70

rbb

r fff

f 6;6

MHzMHz

fr 667.16

10

MHzffLSF rc 333.68667.170 MHzffUSF rc 667.71667.170

MHzf

Bb

33.33

MHzfb 10

Fall 2001 ENZO PATERNOENZO PATERNO 19

MHz70

MHz33.3

EXAMPLEEXAMPLE

LSBLSB USBUSB

MHz667.1MHz667.1

MHz667.71MHz333.68LSFLSF USFUSF

BAUD RATE = 1/3 BIT RATE = 3.33 MEGABAUDBAUD RATE = 1/3 BIT RATE = 3.33 MEGABAUD

Fall 2001 ENZO PATERNOENZO PATERNO 20

8-PSK RECEIVER8-PSK RECEIVER

Fall 2001 ENZO PATERNOENZO PATERNO 21

SIXTEEN PHASE SHIFT KEYING (16-PSK)SIXTEEN PHASE SHIFT KEYING (16-PSK)

• M-M-ARY ARY CODING SCHEME WITH M = 16, N = 4CODING SCHEME WITH M = 16, N = 4• SIXTEEN OUTPUTS PHASES ARE POSSIBLE SIXTEEN OUTPUTS PHASES ARE POSSIBLE • THE INPUT BINARY DATA IS COMBINED INTOTHE INPUT BINARY DATA IS COMBINED INTO GROUPS OF 4 (N = 4) BITS CALLED GROUPS OF 4 (N = 4) BITS CALLED QUADBITSQUADBITS

• QUADBIT QUADBIT CODE: 0000 = PHASE 1 ……….. 1111 = PHASE 16, CODE: 0000 = PHASE 1 ……….. 1111 = PHASE 16,

• 1 SYMBOL = 1 PHASE = 4 BITS1 SYMBOL = 1 PHASE = 4 BITS

BAUD RATEBAUD RATE = 1/4 = 1/4 BIT RATEBIT RATE((SYMBOLS PER SECSYMBOLS PER SEC)) ((BITS PER SECBITS PER SEC))

• WITH 16-PSK, THE ANGULAR SEPARATION BETWEENWITH 16-PSK, THE ANGULAR SEPARATION BETWEEN AJDACENT PHASES IS 360/16 = 22.5 degrees. FOR AJDACENT PHASES IS 360/16 = 22.5 degrees. FOR INTEGRITY TO REMAIN, PHASE SHIFT max = +/- 11.25INTEGRITY TO REMAIN, PHASE SHIFT max = +/- 11.25 degrees degrees

Fall 2001 ENZO PATERNOENZO PATERNO 22

16-PSK GENERATION: OUTPUT PHASES16-PSK GENERATION: OUTPUT PHASES