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Figure 7. Open Loop Frequency Response

CLOSED-LOOP SYSTEM STEP RESPONSE

a) Small - signals analysis.

The transfer function (3) can be written as follows:

(7)

where wo =

is the cutoff frequency

is the dumping factor

By choosing the

ξ value, it is possible to determine the system response to an input step signal.

Examples :

1)

ξ = 1 from which t

2)

ξ =

from which

I

M

V

I

----- s

()

0.044

R

s

---------------

1

s

2

ξω

o

--------------

+

1

2

ξss

2

+

ω

2

----------------------

+

--------------------------------

=

G

R

----------------------------

ξ

R

4R

---------------------------------------

=

I

()

0.044

R

S

---------------

1e

t

2R

-------------------

–

1

t

4R

-------------------

+





–

V

i

⋅









=

1

2

-------

I

()

0.044

R

s

--------------- 1

t

2R

------------------- e

t

2R

-------------------

–

cos

–









V

i

=