zl10036 Zarlink Semiconductor, zl10036 Datasheet - Page 28

• Manufacturer Part Number: zl10036
• Description: Digital Satellite Tuner With Rf Bypass
• Manufacturer: Zarlink Semiconductor

4.3.4
Example 1, conditions:
Because
This result should be rounded down to 17 to ensure that the result is not below the 575 kHz limit. Using this value
for BR, equation 4 can be evaluated:
The result can be rounded to the nearest value, i.e., BF = 18.
Example 2, conditions:
In this case,
Using equation 4, this time with the rounded-down value of 14 for BR:
Rounding to the nearest integer thus gives a value of 59 for BF.
4.4
BR
BF
BR
BF
a. Byte 6: Set RSD = 0 to re-enable baseband filter resistor switching.
b. Byte 7: Set BF6:1 to the value derived in 4.3.3.2, “Calculating the Value of BF“ on page 27.
c. Byte 6: Set RSD = 1 to disable baseband filter resistor switching. This must happen no sooner than a
=
=
=
=
Programming Sequence for Filter Bandwidth Changes
certain time after (b.). This minimum time equals BR/(32 * f
byte BR and f
§
©
------------------- -
575kHz
f
------- -
§
©
f
xtal
------- -
f
f
bw
------- -
f
f
xtal
Filter Bandwidth Programming Examples
bw
xtal
bw
f
f
xtal
bw
×
×
×
(
f
is below 28.2MHz, the value of BR can be evaluated with equation 2:
BR
bw
63
BR
=
)
is above 28.2MHz so using equation 3 to solve for BR:
×
×
×
10.111MHz
----------------------------- -
K
--- -
K
1
K
575kHz
·
¹
xtal
·
¹
=
–
–
1
1
10.111MHz
----------------------------- -
is the reference crystal frequency.
f
f
34.6MHz
xtal
=
xtal
=
§
©
§
©
= 10.111MHz,
-------------------------- -
10.11MHz
= 10.111MHz,
-------------------------- -
10.11MHz
34.6MHz
=
9MHz
17.583
×
(
63
×
×
)
17
14
×
f
f
bw
bw
-------------- -
1.257
×
×
Zarlink Semiconductor Inc.
1
1.257
= 9MHz
= 34.6MHz
1.257
ZL10036
=
·
¹
·
¹
14.647
–
–
28
1
1
=
=
18.02285
59.227
xtal
) seconds, where BR is the decimal value of
Data Sheet