Le58QL022

Data Sheet

47

Zarlink Semiconductor Inc.

84/85h Write/Read Z Filter Coefficients (FIR and IIR)

R/W = 0: Write

R/W = 1: Read

This command writes and reads both the FIR and IIR filter sections simultaneously.

Cxy

= 0 or 1 in the command above corresponds to Cxy = +1 or −1, respectively, in the equation below.

The Z-transform equation for the Z filter is defined as:

Sample rate = 32 kHz

For i = 0 to 5 and 7

Power Up and Hardware Reset (RST) Values = 0190 0190 0190 0190 0190 0190 01 0190 (Hex)

(Hz(z) = 0)

See note under Command 80/81h on page 46.

Note:

Z6 is used for IIR filter scaling only. Its value is typically greater than zero but less than or equal to one. The input to the IIR filter section is first

increased by a gain of 1/Z6, improving dynamic range and avoiding truncation limitations through processing within this filter. The IIR filter output

is then multiplied by Z6 to normalize the overall gain. Z5 is the actual IIR filter gain value defined by the programmed coefficients, but it also in-

cludes the initial 1/Z6 gain. The theoretical effective IIR gain, without the Z6 gain and normalization, is actually Z5/Z6.

D7

D6

D5

D4

D3

D2

D1

D0

Command

1000010

R/W

I/O Data Byte 1

C40

m40

C30

m30

I/O Data Byte 2

C20

m20

C10

m10

I/O Data Byte 3

C41

m41

C31

m31

I/O Data Byte 4

C21

m21

C11

m11

I/O Data Byte 5

C42

m42

C32

m32

I/O Data Byte 6

C22

m22

C12

m12

I/O Data Byte 7

C43

m43

C33

m33

I/O Data Byte 8

C23

m23

C13

m13

I/O Data Byte 9

C44

m44

C34

m34

I/O Data Byte 10

C24

m24

C14

m14

I/O Data Byte 11

C45

m45

C35

m35

I/O Data Byte 12

C25

m25

C15

m15

I/O Data Byte 13

C26

m26

C16

m16

I/O Data Byte 14

C47

m47

C37

m37

I/O Data Byte 15

C27

m27

C17

m17

H

z z

()

z

0

z

1

z

1

–

•

z

2

z

2

–

•

z

3

z

3

–

•

z

4

z

4

–

z

5

z

6

•

z

7

z

1

–

•

•

1z

7

z

•

1

–

–

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

+

•

++

++

=

z

i

C1i

2

m1i

–

•

1C2i

2

m2i

–

1C3i

2

m3i

–

•

1C4i

2

m4i

–

•

+

()

+

[]

•

+

{}

=

z

6

C16

2

m16

–

•

1C26

2

m26

–

•

+

{}

=