TDA8295 Datasheet, PDF (23/77 Pages) NXP Semiconductors – Digital global standard low IF demodulator for analog TV and FM radio

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 channel’s own sound carriers and the N − 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_1
Product data sheet
Rev. 01 — 4 February 2008
© NXP B.V. 2008. All rights reserved.
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