TDA8296 Datasheet, PDF (41/87 Pages) NXP Semiconductors – Digital global standard low IF demodulator for analog TV and FM radio

NXP Semiconductors
TDA8296
Digital global standard low IF demodulator for analog TV and FM radio
Table 39. AFC register (address 25h) bit description
Bit Symbol
Access Value Description
7 to 0 AFC[7:0]
R
-
This is the readout for AFC. AFC contains the
frequency deviation from nominal IF picture carrier.
The format is twos complement, 13.2 kHz steps are
done per LSB. See Table 40 for details. The frequency
deviation could also be given by the following formula:
f_IF – f_nom
=
–----A_---F_----C_------×_----6_-----7_---5_---0_-
512
(kHz)
. For a frequency
deviation from the nominal IF picture carrier greater
than the FPLL pull-in capability (−830.6 kHz to
+843.8 kHz or −1 674.3 kHz to +1 687.5 kHz), the
output reading is undefined. The AFC lock indication
can be taken from the N_H_LOCK information from the
H-sync PLL. The lock occurs inside a frequency
window, which is determined by the pull-in capability of
the FPLL.
Table 40. Calculation of frequency deviation from AFC value
Deviation from nominal AFC[7] AFC[6] AFC[5] AFC[4] AFC[3] AFC[2] AFC[1] AFC[0]
IF frequency^[1]
f_IF = f_nom − 1674.3 kHz 0
1
1
1
1
1
1
1
f_IF = f_nom − 1661.1 kHz 0
1
1
1
1
1
1
0
:
:
:
:
:
:
:
:
:
f_IF = f_nom − 830.6 kHz
0
0
1
1
1
1
1
1
f_IF = f_nom − 817.4 kHz
0
0
1
1
1
1
1
0
:
:
:
:
:
:
:
:
:
f_IF = f_nom − 13.2 kHz
0
0
0
0
0
0
0
1
f_IF = f_nom
0
0
0
0
0
0
0
0
f_IF = f_nom + 13.2 kHz
1
1
1
1
1
1
1
1
:
:
:
:
:
:
:
:
:
f_IF = f_nom + 830.6 kHz
1
1
0
0
0
0
0
1
f_IF = f_nom + 843.8 kHz
1
1
0
0
0
0
0
0
:
:
:
:
:
:
:
:
:
f_IF = f_nom + 1674.3 kHz 1
0
0
0
0
0
0
1
f_IF = f_nom + 1687.5 kHz 1
0
0
0
0
0
0
0
[1] See Section 12 for nominal IF frequencies.
TDA8296
Product data sheet
All information provided in this document is subject to legal disclaimers.
Rev. 1 — 3 March 2011
© NXP B.V. 2011. All rights reserved.
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