Previous Page  26 / 30 Next Page
Basic version Information
Show Menu
Previous Page 26 / 30 Next Page
Page Background

178

CAPITOLO 6

Ampli!catori

S

in

S

u

S

u

S

f

S

f

ε

S

in

ε

+

+

A

(

s

)

F

(

s

)

A

(

s

)

F

(

s

)

Fig. 6.7

Sistema reazionato negativamente (sopra) e positivamente (sotto).

6L FDSLVFH TXLQGL FKH LQ XQ VLVWHPD UHD]LRQDWR SRVLWLYDPHQWH DQFKH XQ SLFFROR GLVWXUER

LQ LQJUHVVR SRWUHEEH LQQHVFDUH OD GLYHUJHQ]D GHO VHJQDOH FLUFRODQWH QHO VLVWHPD VWHVVR LQIDWWL

HVVR FRQWLQXHUHEEH DG DXPHQWDUH SRUWDQGR LQHYLWDELOPHQWH O¶XVFLWD D GLYHUJHUH LQVWDELOLWj

3UREDELOPHQWH L YDUL FRPSRQHQWL QRQ VL GDQQHJJHUHEEHUR SHUFKp XVFHQGR GDOOD ORUR ]RQD GL

OLQHDULWj VDWXUHUHEEHUR O¶RVFLOOD]LRQH LQVWDXUDWDVL 1HL VLVWHPL UHD]LRQDWL QHJDWLYDPHQWH FLz

QRQ DYYLHQH H OD VWDELOLWj q FRQVHJXHQWHPHQWH JDUDQWLWD

6LD L FLUFXLWL UHD]LRQDWL QHJDWLYDPHQWH FKH TXHOOL UHD]LRQDWL SRVLWLYDPHQWH WURYDQR DS

-

SOLFD]LRQH QHL VLVWHPL HOHWWURQLFL $OOD SULPD FDWHJRULD DSSDUWHQJRQR DG HVHPSLR JOL DPSOL

-

¿FDWRUL L IRUPDWRUL HG L ¿OWUL DOOD VHFRQGD JOL RVFLOODWRUL HG L JHQHUDWRUL GL FORFN ,Q VHJXLWR

FL OLPLWHUHPR D FRQVLGHUDUH VROR FLUFXLWL UHD]LRQDWL QHJDWLYDPHQWH D PHQR FKH QRQ YHQJD

VSHFL¿FDWR GLYHUVDPHQWH

,QWURGRWWD OD WRSRORJLD GHL VLVWHPL UHWURD]LRQDWL H OD ORUR FODVVL¿FD]LRQH q SRVVLELOH RUD

YDOXWDUH TXDQWLWDWLYDPHQWH OD ULSURGXFLELOLWj GHOOD IXQ]LRQH GL WUDVIHULPHQWR GL XQ DPSOL¿FD

-

WRUH UHDOL]]DWR VHFRQGR OR VFKHPD GL + 6 %ODFN 'LIIHUHQ]LDQGR OD (T ULVSHWWR DG

A

si

RWWLHQH

1

1

dG

G

dA

A G

loop

=

Eq. 6.10

6H LO JXDGDJQR GL DQHOOR q QHJDWLYR HG LO PRGXOR PDJJLRUH GHOO¶XQLWj OD YDULD]LRQH SHU

-

FHQWXDOH GHO WUDVIHULPHQWR GL DQGDWD

A s

LQÀXHQ]D SRFR R LQ PDQLHUD WUDVFXUDELOH LO WUDVIHUL

-

mento G all’interno del sistema.

,Q GH¿QLWLYD LQ XQ VLVWHPD UHD]LRQDWR QHJDWLYDPHQWH OD ULGX]LRQH GHO JXDGDJQR GL XQ

IDWWRUH SDUL DG ±

G

loop

ULVSHWWR D TXHOOR GHO EORFFR GL DQGDWD FRQVHQWH GL UHQGHUH LO FLUFXLWR

PHQR VHQVLELOH DOOH YDULD]LRQL GL $ SURSULR LQ UDJLRQH GHOOR VWHVVR IDWWRUH 3HU XQ FLUFXL

-

WR UHD]LRQDWR SRVLWLYDPHQWH H VWDELOH

G

loop

VL KD LQYHFH XQ WUDVIHULPHQWR PDJJLRUH

GHOO¶DQGDWD PD DQFKH VHQVLELOH DOOH YDULD]LRQL GL $ LQ UDJLRQH GHO VROLWR IDWWRUH ±

G

loop

4XHVWH FRQVLGHUD]LRQL KDQQR XQD LPPHGLDWD DSSOLFD]LRQH SUDWLFD 6XSSRQLDPR LQIDWWL GL

GRYHU UHDOL]]DUH XQ DPSOL¿FDWRUH HOHWWURQLFR FRQ XQ¶HOHYDWD VWDELOLWj GHO JXDGDJQR YDULD

-

]LRQH GHO

±

1RQ VL SRWUHEEH SHQVDUH GL UHDOL]]DUH XQ VLPLOH DPSOL¿FDWRUH DG DQHOOR