3. What is anti Aliasing filter?
Ans:An anti-aliasing filter (AAF) is a filter used before a signal sampler to restrict the bandwidth of
a signal to satisfy the Nyquist–Shannon sampling theorem over the band of interest.
6ystem. Moths-2
Control System
is
ot
type
Control System
Openloop
o n the
4Openloop
Cothol
a
n
input
dependS
System
othe
the
Outpu
hieh
but h e
înput
or
otne
the Controllon 1s îndependent
Syötem
system.This
the
Output op
feedback loop omd thus
also Knoon as
mon
any
feed baak
eontrolled
S6tem
/
do not eontain
eontrollet
Siqna
Rrocess
/e
rage N.
Damgun
8Dlh
Avs
hamplhold pioss
Sanple aad holdalso nounas_alloa cut is
am analg douica that samples Copluns V ualtage
aLontnubualy Laxyingq analeg signal and holds AX ualis
at a cohwtat auul
Wwe
aaeeáai inisaumAexd
hey _aselupicaty LAndm_anala-tn-dialta/
ConuwloxA
enat uaualions m wpu gna
hat cau Loxup
he ConuxALo2 0oLsA.
5 marks
QI llustrate feedback control system (advantages and disadvantages)
FEEDBACK cONTROLL sYSTEM
The feedback is an electric signal which is transferred from the output to the
controller, so the controller would be able to calculate how the output is
different from the required value. The controller would know the past state of
the system output with the help of this feedback signal. The controller would
calculate the error and it would vary the system input to get the required
Output. The closed-loop system is also caled a feedback system because it
fed back the output into the input so that the errors can be cleared and the
required output quality can be maintained. The feedback control is to remove
the measured disturbances. The feedback controls are automated and it
should do the sensing, calculating, and manipulating to be performed by the
equipment, and that each element must communicate with the other
elements in the control system.
Home furnace control system must control the temperature in the room and
kept it constant. As in open loop system a timer is used to switch on the furnace
for some time and then switch it off, accuracy is not obtained.
ADVANTAGES AND
DISADVANTAGE
OF
FEEDBACK CONTROL
SYSTEM
The following
advantages are the fundamental reasons for using feedback.
1. Many unnecessary disturbances and noise signals from
outside the
system
can
be
rejected.
2. The change in the performance of the system due to
parameter variations is reduced.
3. The steady-state error of the system can be relatively small.
4. The transient behavior of the process can be
easily
manipulated.
5. The feedback is compared with the desired state in order to
take corrective measures.
On the other hand, using feedback can have several
disadvantages:
1. The system is
complicated by the increased number of
components, such as sensors and error detectors.
2. The overall gain of the system is reduced and must
be
compensated for in the design.
3. The system may not be stable
(it may oscillate
or
depart
greatly from the desired output), even though the comparable
open-loop system is stable.
4. The error detector is
necessary in order to compare two
states.
5. If there is
a
change
in
an
Output,
it will affect the
system input.
th gm)
NB
p(
uph vetoad watk -leoels
tb tuhla amol.
unskuhk Cd,
Pankiv
9 Deruhe judbatk Cmtral wth a uutab e lncmpk
A
A dbe tk
CnEhol
e
Adtom
blot ugatm
be
om
Jolliw ima
apouaserudeol btha.
SUPo
Omtuole
tomTYP
eedbo-k
Sc Poin ives
C) ave nol
olewucl o/ eKathunl P 0t
ytlm
suumnna
m obn
at the load sid
50RPM.
Gutdlosd o/p Secl omob
Now, le ot on wtomt otvmewe t
peOc
l000RM whioh
ano
(il oto/P)
o valc
e thom fuolsiUc /e.
SPecc
tte volu
o
[000RMqu
d
ean (ovun (doietdlg)-(oetuelojr qe
bo set povml
Ond
the sct Pemt Csleulates tha
r 0 l h e r e U N = b0 0 KY). has dvu
i
nal )
s n t bo the
uadub
Cordbydl b
DU0N Cm
te.
Hma
(uene, tve enoh
SCpountd oomtnoler
he m obo?
9uwrs akbha olp of tho
Cmk dlo
hergr
Crg
1n5 RPM b
o/p
Cvnkol
his
d c to
(00-1250)
O
p
cek pöumt & sek
punes v e s t t
9h0 RPM whith
Cm CntnoU ecln@es the
pnu l s wul be
opeolool unkil K
olanrec 0/elwre 1500 KPM) DA
woless
accn qeen
on
we aeE n....
nkl A nles seE
oerUron
Acouo,
we wnt
t
we meCc ehomge
b
Chouce
vnt,
Ouw denoudl
Dwr
d
aontinaussysfem.Stte5 diftene.
18. Detine disereteand
and
=>sceter
Rortinoos
Discretesystem
Indiscretesystems,both nput and ottPutsimabone
The coiasle
diserete
signals.
inthe diseretesystems
o system the changesa
ime. In this tPe
The
ste od volalsl
One predominontlydiscottrnuoUs
ane
d
set of
in diereatesystem chonge only at ca discvete
vcoy
wit
points in
time.
Diserete
system_
continuOUSSYStem
Ce
ROo
eontinuoUS
Systems
those tpes ot systemsin
which inputand outputsignal
coe the same at
both he ends.In this tpe of system,vcoicuble
changes
with ime and
any pe oVeanicdhionis not toundi
+he input andoutput
Tn responseto
signol.
imput
a
Uous sysfem
an
Signo, contin
3enerater
output
signa
s
he
Diserete
system
continOUssy sten
)The stutevasiiableehange) The
ony ot a discrekseto
)Diserete
model
is
stotevamiables
ehange
Aime. eonttnvously
oen time.
n
appropmcte
Continuousmodelis
appropiate system
with a eontinU
nUs tute
Fr
sYstem havingdiserete
Stocte an d chonger odt
a
Paoticulan
tnepointond
thatchangex
fr
remains in thotrstute
Over
Sene time.
+ime
emtinuous(y
i)
)
Most disevetetime system
mo st eoinuovstime
sents
houw
discrete
SYStem
repre
representhot
one
a
signa
trunsfumme
d
Contin
vovssiqnol ane transter
rd
a diffeertial
dfferenceequahions.
iv)Adiserete
simulation
medelidA
is
C
not
alnays sed
disCreteystem
Instant
sote change
syste
hat
diven-ue oe
o hodel
eqvatios
corrtinuau
s mo del
VJed fu mo dela
not
aulwcuy
As
CcntinvOUs SyStevm
in a
v
siu
Continuous
lotion sutabk
-stue
tinite
aitendijeret
systers
that
actiite
Change
aroventime.
s
aliead
reeactit tur
Cmstanty