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SAA4970T/V2

Economical video processing IC (ECOBENDIC)

Philips Electronics 

Philips Semiconductors

Economical video processing IC

(ECOBENDIC)

Preliminary specification

SAA4970T

16

handbook, halfpage

14

IH_PeakingI

(dB) 12

10

8

6

4

2

0

0

(1) β = 1⁄2.

(2) β = 1⁄4.

(3) β = 1⁄8.

(4) β = 0.

MGE099

(1)

(2)

(3)

(4)

1/4fs

1/2fs

Fig.9 Peaking transfer function with variation of β

(α = 1⁄2).

12

handbook, halfpage

10

IH_PeakingI

(dB)

8

6

4

2

0

0

MGE100

(1)

(2)

(3)

1/4fs

1/2fs

(1) β = 1⁄2.

(2) β = 1⁄4.

(3) β = 1⁄8.

Fig.10 Peaking transfer function with variation of β

(α = 0).

PHASE COMPENSATION

handbook, h0alfpage

Φnlp

(1)

(2)

(f/fs)

(3)

(4)

−1/2π

MGE101

−π

0

(1) λ = 0.

(2) λ = 1⁄8.

(3) λ = 1⁄4.

(4) λ = 1⁄2.

0.125

0.25

0.375 f/fs 0.5

Fig.11 Phase spectrum of NLP filter transfer

function.

To compensate for a non-linear phase characteristic

before the A/D converter, this filter will compensate such

behaviour with a pulse response of [−λ, 1 + λ]. λ can be

programmed for the values 0, 1⁄8, 1⁄4 and 1⁄2.

An 8-bit word width is re-obtained by means of clipping at

0 and 255.

FRAMING AND BLANKING

Blanking is done with switching Y to value 16 and UV to

value 0 (in twos complement) on command of the BL

signal.

Framing is done by switching Y and the higher nibble of U

and V to certain programmable values (frame Y and

frame UV) on command of the signal KAD.

If the pixel repetition function is chosen the last values from

the video remain repeated instead of the fixed values.

The range of the output signal YO can be selected between

8 and 9 bits. In case of 8 bits for the nominal signal there

is room left for under and overshoot (adding up to a total of

9 bits); in case of selecting all 9 bits of the luminance D/A

converter for the nominal signal any under or overshoot

will be clipped.

1996 Oct 25

10

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