Reference Instruction Manual

7.1.1 Link Parameterization
The basic continuous-time second-order element is a filter with a unity DC gain:
DCsEs
BAsEs
B
D
2
2
++
++
⋅
Note that this element is very general: It can be used, for example, as a notch filter, a
low-pass complex pole filter, a double-lead element or a single pole.
The equivalent discrete form is:
21
2
21
2
0
azaz
bzbzb
++
++
Order Parameter Description Comment
1
k
1
b
0
+ b
1
+ b
2
Float, represented by a long value
2
k
2
-(b
1
+ b
2
) Float, represented by a long value
3
k
3
-b
2
Float, represented by a long value
4
k
4
a
2
Float, represented by a long value
Table 7-6: Fixed Link Parameters
The parameter a
1
is obtained explicitly by a
1
= b
1
+ b
1
+ b
1
- a
1
- 1.
7.2. Examples of Filter Implementation
The following examples illustrate how the more common filter links can be
implemented. Each example calculates the parameters b
0
, b
1
, b
2
, a
1
and a
2
.
Note that the frequency response of a discrete-time filter depends on the sampling
time. In the following examples, you should use sampling time T=2×TT[1].
7.2.1 Low-pass (Complex Pole) Element
(Represented by Second-order Block)
The basic continuous-time complex pole element is:
22
2
2 ωω
ω
+⋅⋅⋅+
s
d
s
where:

f⋅=
π
ω 2
is the angular frequency.

f [Hz] is the pole frequency.
SimplIQ for Steppers Application Note Filters
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