2 Functional Description
2.1 Analog Processing and A/D Converters
Figure 2−1 shows a functional diagram of the analog processors and ADCs. This block provides the analog interface
to all video inputs. It accepts up to 10 inputs and performs source selection, video clamping, video amplification, A/D
conversion, and gain and offset adjustments to center the digitized video signal.
TVP5146 Analog Front End
VI_1_A
VI_1_B
VI_1_C
M
U
X
Clamp
PGA
10-Bit
ADC
CH1 A/D
VI_2_A
VI_2_B
VI_2_C
M
U
X
Clamp
PGA
10-Bit
ADC
CH2 A/D
Line-Locked Sampling Clock
VI_3_A
VI_3_B
VI_3_C
M
U
X
Clamp
PGA
10-Bit
ADC
CH3 A/D
VI_4_A
Clamp
PGA
10-Bit
ADC
CH4 A/D
Figure 2−1. Analog Processors and A/D Converters
2.1.1
Video Input Switch Control
The TVP5146 decoder has 4 analog channels that accept up to 10 video inputs. The user can configure the internal
analog video switches via I
2
C. The 10 analog video inputs can be used for different input configurations, some of
which are:
•
•
•
•
Up to 10 selectable individual composite video inputs
Up to four selectable S-video inputs
Up to three selectable analog YPbPr/RGB video inputs and one CVBS input
Up to two selectable analog YPbPr/RGB video inputs, two S-video inputs, and two CVBS inputs
The input selection is performed by the input select register at I
2
C subaddress 00h (see Section 2.11.1).
2−1
TI [ TEXAS INSTRUMENTS ]
