No se encuentranentradas de índice.
CONTENIDO RUIDO Y MODULACIÓN ANGULAR............................. ANGULAR.................................................................. ..................................... 2 TRIANGULO TRIANGULO DE RUIDO DE FM.............. FM......................... ..................... ..................... ..................... ........................2 ..............2 MODULACION DE FRECUENCIA DEBIDA A UNA SEÑAL DE INTERFERENCIA.3 PREENFASIS Y DEENFASIS...............................................................................4 TEOREMA DE MUESTREO.............. MUESTREO........................ ..................... ....................................................... ............................................ 6
UNIERSIDAD DE LAS FUERAS ARMADAS ESPEL
INDICE DE FIGURAS.
I!g%!i%r5a E"%+/r,!i+a % I!*/ru&%!/a+i,! I!*/ru&%!/a+i,!
Figura . Tria!gu"# $% rui$# $% FM.......... FM .................... ..................... ....................................... ............................2 2 Figura 2. Diagra&a $% u!a r%$ $% 'r%(!)a*i*..........................................4 Figura 3. R%"a+i,! *%-a" a rui$# %! FM *i! 'r%(!)a*i*..............................4 Figura 4. R%"a+i,! *%-a" a rui$# %! FM +#! 'r%(!)a*i*............................. 'r%(!)a*i*............................. Figura . Cir+ui/# $% u! Pr%(!)a*i* 0 $%(!)a*i*.................... $%(!)a*i*........................................ .................... Figura 6. E*'%+/r# $% *a"i$a 'ara u! +ir+ui/# $% &u%*/r%# 0 r%/%!+i,! *i! $i*/#r*i,! '#r a"ia*.................... a"ia*............................... ..................... ..................... ..................... ..................... ..................... .......... 6 Figura 1. E*'%+/r# $% *a"i$a 'ara u! +ir+ui/# $% &u%*/r%# 0 r%/%!+i,! +#! $i*/#r*i,! '#r a"ia*....................... a"ia*................................. ..................... ...................... ................................ ..................... 6
SISTEMAS DE COMUNICACIONES Au!no" #RYAN $ILA CONSULTA #I#LIOGRAFICA
SE%TO NI&EL RUIDO Y MODULACIÓN ANGULAR
'( de )unio *'(+
Cua!$# *% agr%ga rui$# /(r&i+# +#! $%!*i$a$ %*'%+/ra" +#!*/a!/% a u!a *%-a" $% FM 'r#$u+% u!a $%*7ia+i,! i!$%*%a$a $% "a )r%+u%!+ia $% "a '#r/a$#ra. La &ag!i/u$ $% %*/a $%*7ia+i,! !# $%*%a$a $%'%!$% $%" *igui%!/% 'ar8&%/r#9 •
La a&'"i/u$ r%"a/i7a $%" rui$# +#! r%*'%+/# a "a '#r/a$#ra.
Cua!$# *% $%$u"a %*/a $%*7ia+i,! i!$%*%a$a $% '#r/a$#ra *% /ra!*)#r&a %! rui$# *i *u* +#&'#!%!/%* $% )r%+u%!+ia :u%$a! $%!/r# $%" %*'%+/r# $% )r%+u%!+ia* $% i!)#r&a+i,!. La )#r&a %*'%+/ra" $%" rui$# $%$u"a$# $%'%!$% $% *i *% u*a $%$u"a$#r $% PM # $% FM. E" 7#"/a;% $% rui$# %! "a *a"i$a $% u! $%$u"a$#r $% PM %* +#!*/a!/% r%*'%+/# a "a )r%+u%!+ia &i%!/ra* :u% %! "a *a"i$a $% u! $%$u"a$#r $% FM au&%!/a %! )#r&a "i!%a" +#! "a )r%+u%!+ia. A %*/# *% "% *u%"% ""a&ar /ri8!gu"# $% rui$# $% FM.
TRIANGULO DE RUIDO DE FM •
•
S% 7% :u% %" 7#"/a;% $% rui$# $%$u"a$# %* i!<%r%!/%&%!/% &a0#r 'ara &a0#r%* )r%+u%!+ia* $% *%-a" $u"a$#ra. La )#r&a %*'%+/ra" $%" rui$# $%$u"a$# $%'%!$% $% *i *% u*a $%$u"a$#r $% PM # $% FM.
FM PM
D%$u"a$#r
E" rui$# au&%!/a %! )#r&a "i!%a" +#! "a )r%+u%!+ia
D%$u"a$#r
E" rui$# %* +#!*/a!/% r%*'%+/# a "a )r%+u%!+ia
Fi,ura (. Trian,uo de ruido de FM
MODULACION DE FRECUENCIA DE#IDA A UNA SE-AL DE INTERFERENCIA La $%*7ia+i,! i!*/a!/8!%a $% )r%+u%!+ia f ( t ) %* "a 'ri&%ra $%ri7a$a $% "a $%*7ia+i,! i!*/a!/8!%a $% )a*%. Cua!$# %" +#&'#!%!/% $% "a '#r/a$#ra %* &u+<# &a0#r :u% %" 7#"/a;% $% rui$# $% i!/%r)%r%!+ia "a $%*7ia+i,! a'r#=i&a$a $% )a*% %*9
θ ( t ) =
Vn sen ( Wnt + θ n ) rad Vc
Y *a+a!$# "a 'ri&%ra $%ri7a$a *% #>/i%!%9 ∆ w (t ) =
Vn rad wnCos ( wnt + θ n ) Vc s
E!/#!+%* "a $%*7ia+i,! &8=i&a $% )r%+u%!+ia %*9 ∆ w max=
∆ f max=
Vn rad wn Vc s
Vn f n [ H z ] Vc
La $%*7ia+i,! &8=i&a $% )r%+u%!+ia f %* u!a )u!+i,! $% "a )r%+u%!+ia $% "a *%-a" $u"a$#ra 0 $%" 5!$i+% $% $u"a+i,!. A*5 'arra u!a )r%+u%!+ia $u"a$#ra $% rui$# fn "a $%*7ia+i,! &8=i&a $% )r%+u%!+ia %*9 ∆ fmax=m fn [ H ]
E! $#!$% & %* igua" a" 5!$i+% $% $u"a+i,! ?&@@. S% 7% :u% &i%!/ra* &8* "%;#* *% $%*'"aa "a )r%+u%!+ia %* &a0#r. P#r +#!*igui%!/% "a* )r%+u%!+ia* $% rui$# :u% 'r#$u+%! +#&'#!%!/%* %! %" %=/r% a"/# $%" %*'%+/r# $% )r%+u%!+ia* $% *%-a" $u"a$#ra 'r#$u+%! &8* $%*7ia+i,! $% )r%+u%!+ia 'ara "a &i*&a $%*7ia+i,! $% )a*% :u% "a* )r%+u%!+ia* :u% %*/8! %! %" "a$# i!)%ri#r. L#* $%$u"a$#r%* $% FM g%!%ra! u! 7#"/a;% $% *a"i$a :u% %* 'r#'#r+i#!a" a "a $%*7ia+i,! $% )r%+u%!+ia % igua" a "a $i)%r%!+ia %!/r% "a )r%+u%!+ia $% "a '#r/a$#ra 0 "a )r%+u%!+ia $% "a *%-a" i!/%r)%r%!/%. P#r "# /a!/# +#&'#!%!/%* $% rui$# $% )r%+u%!+ia a"/a* 'r#$u+%! &8* rui$# $%$u"a$# :u% "#* +#&'#!%!/%* $% )r%+u%!+ia >a;a. La r%"a+i,! $% *%-a"arui$# a "a *a"i$a $% u! $%$u"a$#r $% FM $%>i$a a "a $%*7ia+i,! $% )r%+u%!+ia !# $%*%a$a $% u!a *i!u*#i$% i!/%r)%r%!/% %* "a r%"a+i,! $% "a $%*7ia+i,! $% )r%+u%!+ia 'i+# $%>i$a a "a *%-a" $% i!)#r&a+i,! +#! "a $%*7ia+i,! $% )r%+u%!+ia 'i+# $%>i$a a "a *%-a" i!/%r)%r%!/%.
S ∆ f debido ala señal = N ∆ f debidoal ruido
2
$REENFASIS Y DEENFASIS E" 'r%(!)a*i* %* u!a /(+!i+a $% r%$u++i,! $% rui$# :u% +#!*i*/% %! au&%!/ar "a a&'"i/u$ $% "a* a"/a* )r%+u%!+ia* 'u%*/# :u% %*/a* *#! &8* *%!*i>"%* a" rui$#. E! Eur#'a "a +#!*/a!/% $% /i%&'# $%" 'r% (!)a*i* %* $% * &i%!/ra* :u% %! A&(ri+a %* $% 1*. E*%!+ia"&%!/% "a r%$ $% 'r%(!)a*i* '%r&i/% :u% "a* *%-a"%* $u"a$#ra* $% a"/a )r%+u%!+ia $u"%! "a '#r/a$#ra a u! !i7%" &8* a"/# 0 '#r "# /a!/# 'r#$u+a! &a0#r $%*7ia+i,! $% )r%+u%!+ia &a!/%!i%!$# u!a r%"a+i,! *%-a" rui$# u!i)#r&%.
Fi,ura *. Dia,ra!a de una red de re/n0asis. E" rui$# %! "a* )r%+u%!+ia* &8* a"/a* $% *%-a"%* $u"a$#ra* /i%!% %! )#r&a i!<%r%!/% &a0#r a&'"i/u$ :u% %! "a* )r%+u%!+ia* &8* >a;a*. P#r "# a!/%ri#r 'ara *%-a"%* $% i!)#r&a+i,! +#! !i7%" u!i)#r&% $% *%-a" *% 'r#$u+% u!a r%"a+i,! *%-a" rui$# !# u!i)#r&% 0 "a* )r%+u%!+ia* &8* a"/a* $% *%-a"%* $u"a$#ra* /i%!%! &%!#r r%"a+i,! $% *%-a" rui$# :u% "a* )r%+u%!+ia* &8* >a;a* +# *% 7% %! "a gura *igui%!/%.
Fi,ura 1. Reaci2n se3a a ruido en FM sin re/n0asis E! %*/a gra+a "a r%"a+i,! *%-a" rui$# %* &%!#r %! "#* %=/r%* $% a"/a )r%+u%!+ia $%" /ri8!gu"#. Para +#&'%!*ar %*/# "a* *%-a"%* $u"a$#ra* *% %!)a/ia! # r%)u%ra! %! a&'"i/u$ %! %" /ra!*&i*#r a!/%* $%
r% "a r%"a+i,! $% *%-a" a rui$#. AIIi *% 7% :u% 'r#$u+%! u!a r%"a+i,! &8* u!i)#r&% $% *%-a" a rui$# %! /#$# %" %*'%+/r# $% )r%+u%!+ia* $% "a *%-a" $u"a$#ra.
Fi,ura 4. Reaci2n se3a a ruido en FM con re/n0asis U!a r%$ $% 'r%(!)a*i* %* u! "/r# $% 'a*a a"/#* ?%* $%+ir u! $i)%r%!+ia$#r 0 u!a r%$ $% $%(!)a*i* %* u! "/r# $% 'a*a >a;#* ?u! i!/%gra$#r a 3
+#!/i!ua+i,! *% &u%*/ra "#* $iagra&a* %*:u%&8/i+#* 'ara u!a r%$ $% 'r%(!)a*i* a+/i7a 0 u!a r%$ $% $%(!)a*i* 'a*i7a.
Fi,ura 5. Circuito de un $re/n0asis 6 de/n0asis La )r%+u%!+ia $% +#r/% %* $#!$% *% %&'i%a %" 'r%(!)a*i* 0 "a $%%!)a*i* *% "# $%/%r&i!a +#! "a +#!*/a!/% $% /i%&'# RC # LR $% "a r%$. La $%!i+i,! &a/%&8/i+a $% "a )r%+u%!+ia $% :ui%>r% %*9 f b=
1
1
; f b= 2 π ∗ RC 2 π ∗ L / R
C# *% 'u%$% a'r%+iar %! "a gura a!/%ri#r %* u!a r%$ a+/i7a $% 'r%(!)a*i* 0 !# 'a*i7a '#r:u% u!a r%$ 'a*i7a $% 'r%(!)a*i* 'r#$u+% '%r$i$a* %! /#$a* "a* )r%+u%!+ia* 0 *% i!/r#$u+% &8* '%r$i$a* %! "a* )r%+u%!+ia* &%!#r%* $% "a *%-a" $u"a$#ra.
TEOREMA DE MUESTREO E" /%#r%&a $% &u%*/r%# $% N0:ui*/ %*/a>"%+% "a )r%+u%!+ia &5!i&a $% &u%*/r%# ( f s )
:u% *% 'u%$% u*ar %! $%/%r&i!a$# *i*/%&a. Para :u% u!a
&u%*/ra *% r%'r#$u+a +#! %=a+/i/u$ %! %" r%+%'/#r *% $%>% &u%*/r%ar +ua!$# &%!#* $#* 7%+%* +a$a +i+"# $% "a *%-a" a!a",gi+a $% %!/ra$a
( f a ) .
E! +#!*%+u%!+ia "a )r%+u%!+ia &5!i&a $% &u%*/r%# %* igua" a" $#>"% $% "a )r%+u%!+ia &8=i&a $% "a %!/ra$a $% au$i#. Si 'r#$u+ir8 $i*/#r*i,!.
f s %* &%!#r :u%
f a
*%
A %*/a $i*'#*i+i,! *% "a ""a&a $i*'#*i+i,! '#r a"ia* # '#r $#>"% $% i&ag%!. La )r%+u%!+ia $% &u%*/r%# &5!i&a $% N0:ui*/ %*9 f s f a
E! $,!$%H f s )r%+u%!+ia &5!i&a $% &u%*/r%# $% N0:ui*/ ?J f a &8=i&a )r%+u%!+ia :u% *% $%>% &u%*/r%ar ?J
E! %*%!+ia u! +ir+ui/# $% &u%*/r%# 0 r%/%!+i,! %* u! $u"a$#r $% AM. E" i!/%rru'/#r %* u! $i*'#*i/i7# !# "i!%a" :u% /i%!% $#* %!/ra$a*9 %" 'u"*# $% &u%*/r%# 0 "a *%-a" a!a",gi+a $% %!/ra$a. E! +#!*%+u%!+ia %!/r% %*a* $#* *%-a"%*
4
)u!$a&%!/a" $%" 'u"*# $% &u%*/r%# *u* )r%+u%!+ia* $% *u&a 0 $% $i)%r%!+ia ( f s ! f a ) /#$a* "a* ar&,!i+a* 0 *u* 'r#$u+/#* +rua$#*.
Fi,ura 7. Esectro de saida ara un circuito de !uestreo 6 retenci2n sin distorsi2n or aias
La g. 1 &u%*/ra %" r%*u"/a$# $% u!a )r%+u%!+ia a!a",gi+a $#!$% "a* )r%+u%!+ia* "a/%ra"%* $% u!a ar&,!i+a *% 'a*a! # $%*'"i%ga! a!$a "a/%ra" $% #/ra ar&,!i+a. La )r%+u%!+ia :u% *% 'a*a %* u! a"ia* # r%'r#$u++i,! $% "a *%-a" $% %!/ra$a ?$% a<5 %" !#&>r% $% K$i*/#r*i,! '#r a"ia*. Fi,ura +. Esectro de saida ara un circuito de !uestreo 6 retenci2n con distorsi2n or aias
#I#LIOGRAFIA9 SISTEMAS DE COMUNICACIONES ELECTRONICA CUARTA EDICIONTOMASI2423