SDA9410
Preliminary Data Sheet
Input signal processing
I²C Bus parameter
Sub address
Description
NOISEME
7Ah
Noise level of the input signal: 0 (no noise), ... , 30 (strong
noise) [31 (strong noise or measurement failed)]
NMSTATUS
7Ch
Signals a new value for NOISEME
1: a new value can be read
0: current noise measurement has not been updated
(compare chapter I²C Bus on page 117)
Table 27
5.4.5
Input read I²C Bus parameter
Letter box detection
The Figure 19 shows the display of a 4:3 letter box source on 16:9 tube. Black bars on
the top and bottom as well as on the right and on the left are visible. It is possible by
vertical and horizontal expansion to display the picture on the whole tube. Therefore only
the first line (Start Line of Active Area - SLAA) and the last line (End Line of Active Area
- ELAA) of the active area must be known. The letter box detection algorithm detects
SLAA and ELAA. Both I²C Bus parameters can be read out via I²C Bus. The µC of the
TV chassis can use both values to calculate the corresponding zoom factor for the
vertical expansion.
SLAA
Vertical and horizontal
expansion
ELAA
Figure 19
Principle of letter box detection
The Figure 20 shows the block diagram of the letter box detection. The letter box
algorithm processes only the luminance data. Each incoming field is processed. The
default value of SLAA is NALPFIPM+PD and of ELAA is 2*ALPFIPM+NALPFIPM+PD-1
(PD - Processing Delay), which means no letter box format source material.
46
Micronas
MICRONAS [ MICRONAS ]
