zl10038 ETC-unknow, zl10038 Datasheet - Page 17

• Manufacturer Part Number: zl10038
• Description: Advanced Modulation Dvb-s2 Compliant Satellite Tuner With Bypass
• Manufacturer: ETC-unknow

The -3 dB bandwidth of the filter (Hz) is given by the following expression:
Where:
f
f
K = 1.257 (constant).
BF = Decimal value of the register bits BF6:BF1, range 0 - 62.
BR = Decimal value of the bits BR4:BR0 (baseband filter reference divider ratio), range 4 - 27.
Methods for determining the values of BR and BF are given in the section on software, please see sect. 4.3 on
page 30.
2.5
The LO on the ZL10038 is fully integrated and consists of three oscillator stages, each with 16 sub-bands. These
are arranged such that the regions of operation for optimum phase noise are continuous over the required tuning
range of 950 to 2150 MHz and over the specified operating ambient conditions and process spread.
The local oscillators operate at a harmonic of the required frequency and are divided down to the required LO
conversion frequency. For each of the three oscillators, the LO prescaler ratio (N
divider ratio is automatically selected by the LO control logic, hence programming of the required conversion
frequency across the oscillator bands is automatic and requires no intervention by the user.
f
---------
BR
-3dB
xtal
xtal
= Crystal oscillator reference frequency (Hz).
= 575 kHz to 2.5 MHz.
= Baseband filter –3 dB bandwidth (Hz) which should be within the range
Local Oscillator
Figure 10 - Normalized Filter Transfer Characteristic (setting 20 MHz)
Zarlink Semiconductor Inc.
ZL10038
17
f
-3dB
8MHz
=
LP
f
--------- -
BR
) is set to ÷4 or ÷2. The required
xtal
≤
×
f
–
(
3dB
BF
≤
+
35MHz
1
)
×
--- -
K
1
Data sheet
.