© 1993 Microchip Technology Inc.

DS00540B-page 15

Implementing IIR Digital Filters

4

01D0 0C12

data

3090

; -A21

01D1 9C1C

data

-25572

; -A22

01D2 56DE

data

22238

; B20

01D3 C1D0

data

-15920

; B21

01D4 56DE

data

22238

; B22

;

;*******************************************************************

;

;*******************************************************************

;

Band Pass Filter Co-efficients

;

;

;

ELLIPTIC

BANDPASS FILTER

;

;

FILTER ORDER =

4

;

Sampling frequency =

2.000

KiloHertz

;

;

BAND

1

BAND

2

BAND

3

;

;

; LOWER BAND EDGE

.00000

.30000

.90000

; UPPER BAND EDGE

.10000

.70000

1.00000

; NOMINAL GAIN

.00000

1.00000

.00000

; NOMINAL RIPPLE

.05000

.05000

.05000

; MAXIMUM RIPPLE

.03644

.03867

.03641

; RIPPLE IN dB

-28.76779

.32956

-28.77647

;

;

;

I

A(I,1)

A(I,2)

B(I,0)

B(I,1)

B(I,2)

;

;

1

-.936676

.550568

.444000

-.865173

.444000

;

2

.936707

.550568

.615540

1.199402

.615540

;

_coeff_bpass

; co-efficients for 1st Cascade section

01D5 3BF2

data

30693/2

; -A11

01D6 DCC4

data

-18041/2

; -A12

01D7 1C6A

data

14549/2

; B10

01D8 C8A1

data

-28350/2

; B11

01D9 1C6A

data

14549/2

; B12

;

; co-efficients for 2nd Cascade section

01DA C40D

data

-30694/2

; -A21

01DB DCC4

data

-18041/2

; -A22

01DC 2765

data

20170/2

; B20

01DD 4CC3

data

39302/2

; B21

01DE 2765

data

20170/2

; B22

;

;*******************************************************************

;

;*******************************************************************

;

Band Stop Filter Co-efficients

;

;

;

ELLIPTIC

BANDSTOP FILTER

;

;

FILTER ORDER =

4

;

Sampling frequency =

2.000

KiloHertz

;

;

BAND

1

BAND

2

BAND

3

;

;

;LOWER BAND EDGE

.00000

.45000

.70000

;UPPER BAND EDGE

.30000

.55000

1.00000

;NOMINAL GAIN

1.00000

.00000

1.00000

;NOMINAL RIPPLE

.05000

.05000

.05000

;MAXIMUM RIPPLE

.03516

.03241

.03517

;RIPPLE IN dB

.30015

-29.78523

.30027

;

;

4-143