16.362 Signal and System I tude modulation with a complex exponential carrier t j c e t c ) ( t j c e t x t y ) ( ) ( ' )) ' ( ( ) ' ( 2 1 ) ( d j C j X j Y ) ( 2 ) ( c j C ) ( ' ) ' ( ) ' ( 2 1 ) ( c c j j X d j X j Y ) ( j X 1 ) ( j Y c 1
15
Embed
16.362 Signal and System I Amplitude modulation with a complex exponential carrier.
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Transcript
16.362 Signal and System I Amplitude modulation with a complex exponential carrier
tj cetc )(
tj cetxty )()(
'))'(()'(
2
1)(
djCjXjY
)(2)( cjC
)(
')'()'(2
1)(
c
c
jjX
djXjY
)( jX
1
)( jY
c
1
16.362 Signal and System I
)(tx
Implementation
tj cetxty )()(
)sin()()cos()()( ttjxttxty cc
x
)sin( tc
x
)cos( tc
)(Re ty
)(Im ty
16.362 Signal and System I Amplitude modulation with a Sinusoidal carrier
)cos()()( ttytw c
)cos()()( ttxty c )()()( ccjC
)(2
1)(
2
1)( cc jjXjjXjW
)( jX
1
)( jW
c2
2
1
c2
Mc
)2cos(12
1)(
)(cos)()( 2
ttx
ttxtw
c
c
)2(
4
1)(
4
1)(
4
1)2(
4
1
)(2
1)(
2
1)(
cc
cc
jjXjXjXjjX
jjYjjYjW
16.362 Signal and System I Synchronous demodulation
)cos()( ttc c
)cos()()( ttxty c)()()( ccjC
)(2
1)(
2
1)( cc jjXjjXjY
)( jX
1
)( jY
c
2
1
c)( jY
cc
2
1
16.362 Signal and System I
)(tx
Implementation
)cos()()( ttxty c
)cos( tc
x)(ty
x
)cos( tc
co
2
co
)( jH
Low pass filter
)(tw
16.362 Signal and System I Asynchronous demodulation
)cos()()( ttxAty c
)()(2
1)()(
2
1)( cccc jjAjjXjjAjjXjY
)( jX
1
)( jY
c
2
1
c
)( cA )( cA
16.362 Signal and System I
Asynchronous )( jY
c
2
1
c
)( cA )( cA
Synchronous
)( jY
c
2
1
c
16.362 Signal and System I
Asynchronous
Synchronous
16.362 Signal and System I Asynchronous demodulation
)cos()()( ttxAty c
)()(2
1)()(
2
1)( cccc jjAjjXjjAjjXjY
)( jY
c
2
1
c
)( cA )( cA
ss
16.362 Signal and System I Frequency-division multiplexing
)(1 tx x
)cos( 1tc
)(2 tx x
)cos( 2tc
)(txn x
)cos( tcn
+ )(tw
)( jW
1c1c 2c 3c2c3c
16.362 Signal and System I Frequency-division multiplexing -- demodulation
1
cn
)(1 jH
Bandpass filter Low pass filter
1
Mx
)cos( tcn
M
1
cn
)(txn
16.362 Signal and System I Single-sideband sinusoidal amplitude modulation
)( jW
cc
0,
0,)(
j
jjH
)(1 tx
x
)cos( 1tc
x
+
)sin( 1tc
16.362 Signal and System I Single-sideband sinusoidal amplitude modulation
)( jY
cc
0,
0,)(
j
jjH
)(1 tx
x
)cos( 1tc
x
+
)sin( 1tc
16.362 Signal and System I Single-sideband sinusoidal amplitude modulation