TVP6000CPFP datasheet(18/57 Pages) TI

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2–6

Vertical and horizontal over-scan compensation ratios are independently controlled by two pairs of registers.

The VDTAH and VDTAL register pair define the vertical scaling ratio and the HDTAH and HDTAL register

pair define the horizontal scaling ratio. The scaling ratio equations are given in the register description

section. An over-scan compensation ratio up to 12.5% in both vertical and horizontal directions is supported.

When enabled, three modes of vertical scaling and two modes of horizontal scaling are provided for optimal

performance of the target application. For computer graphics and text intensive static images, mode 2

vertical scaling (VSC[1:0] = 2) should be used for maximum flicker reduction. For DVD playback, mode 3

(VSC[1:0] =3) should be used for sharpness. The nearest neighbor mode is provided only for comparison

and diagnostic purposes, and should not be used for normal applications.

Finally, the scaled image can be placed on the TV screen at a location defined by the VOFS and HOFS

registers. VOFS and HOFS define the location of the upper left corner of the output image. See the

definitions of the VOFS and HOFS registers for details.

Note that the SWPF bit is provided for test and diagnostic purposes. For normal applications, this bit must

be set to 0 at all times.

2.5

Video Encoder

2.5.1

Luminance Encoding

Programmable gain is first applied to the luminance data output from the data manger or scaling processor

depending on whether the TVP6000 is in regular or scan-conversion mode. The luminance gain is defined

by the GAIN_Y register at subaddresses 5F and 60. The horizontal sync, vertical sync, and setup insertion

are then performed. Both black level and blank level are programmable through the BLACK_LEVEL and

BLANK_LEVEL registers at subaddresses 5D and 5E, respectively.

All of the transition edges of the luminance signal such as the sync edges and active video edges are

properly shaped and filtered to limit the bandwidth within the standards.

2.5.2

Luminance Low-Pass and Interpolation Filter

After all of the necessary components of the luminance signal have been added, the resultant signal is

low-passed and interpolated to a 2x pixel rate. This 2x interpolation simplifies the external analog

reconstruction filter design and improves the signal-to-noise ratio. Refer to Figure 2–6 for the filter frequency

response.

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