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TDA8295_09 Datasheet, PDF (24/83 Pages) NXP Semiconductors – Digital global standard low IF demodulator for analog TV and FM radio | |||
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NXP Semiconductors
TDA8295
Digital global standard low IF demodulator for analog TV and FM radio
9.3.2 Diverse functions (includes tuner IF AGC Pin mode)
Table 14. DIV_FUNC register (address 02h) bit description
Legend: * = default value.
Bit
Symbol Access Value Description
7
AGC_SEL R/W
It determines the tuner IF AGC output Pin mode. The
open-drain output can be used in special applications in
need of a higher control voltage.
0*
Normal mode
1
Open-drain mode
6
AGC_TRI R/W
When AGC_TRI is set to logic 1 the tuner IF AGC output
pin is in 3-state mode. This mode is useful for paralleling a
channel decoder for instance.
0*
Normal mode
1
3-state mode
5 and 4 -
R/W -
not used
3
-
R/W 0
reserved, must be set to logic 0
2
POL_DET R/W
The polarity detector ensures the proper polarity of the
video signal. So, the sync impulses of the video output are
near ground level.
0
polarity detector off
1*
polarity detector on
1
VID_MOD R/W
Selects video modulation. The only standards with positive
video modulation are L and L-accent.
0*
negative video modulation
1
positive video modulation
0
IF_SWAP R/W
When HIGH, the demodulator expects a swapped IF
spectrum. This is the case in L-accent standard. This option
is also built in for flexibility reasons.
0*
normal IF spectrum expected
1
swapped IF spectrum expected
9.3.3 ADC headroom
Table 15. ADC_HEADR register (address 03h) bit description
Legend: * = default value.
Bit Symbol
Access Value Description
7 to 4 -
R/W -
not used
3 to 0 ADC_HEADR[3:0] R/W
ADC_HEADR adjusts the needed headroom for the
wanted channelâs own sound carriers and the N â 1
adjacent sound carriers (PC in L-accent standard).
The ADC headroom is related to the sum of all
signals. This function is built in for debugging
purposes.
0001* ADC headroom 3 dB
0010 ADC headroom 6 dB
0100 ADC headroom 9 dB
1000 ADC headroom 12 dB
TDA8295_C2_2
Product data sheet
Rev. 02 â 27 November 2009
© NXP B.V. 2009. All rights reserved.
24 of 83
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