ADV7189BKSTZ Analog Devices Inc, ADV7189BKSTZ Datasheet - Page 34

• Manufacturer Part Number: ADV7189BKSTZ
• Description: IC DECODER VIDEO W/ADC 80LQFP
• Manufacturer: Analog Devices Inc
• Type: Video Decoderr

Specifications of ADV7189BKSTZ

• Applications: Set-Top Boxes, Video Players, Recorders
• Voltage - Supply, Analog: 3.15 V ~ 3.45 V
• Voltage - Supply, Digital: 1.65 V ~ 2 V
• Mounting Type: Surface Mount
• Package / Case: 80-LQFP
• Resolution (bits): 12bit
• Input Format: Analog
• Output Format: Digital
• Adc Sample Rate: 54MSPS
• Power Dissipation Pd: 450mW
• No. Of Input Channels: 12
• Supply Voltage Range: 3V To 3.6V
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

ADV7189B
CHROMA TRANSIENT IMPROVEMENT (CTI)
The signal bandwidth allocated for chroma is typically much
smaller than that of luminance. In the past, this was a valid
way to fit a color video signal into a given overall bandwidth
because the human eye is less sensitive to chrominance than
to luminance.
The uneven bandwidth, however, can lead to visual artifacts in
sharp color transitions. At the border of two bars of color, both
components (luma and chroma) change at the same time (see
F igure 18). Due to the higher bandwidth, the signal transition
1 9 4 H
of the luma component is usually a lot sharper than that of the
chroma component. The color edge is not sharp but is blurred,
in the worst case, over several pixels.
The chroma transient improvement block examines the input
video data. It detects transitions of chroma, and can be pro-
grammed to “steepen” the chroma edges in an attempt to
artificially restore lost color bandwidth. The CTI block,
however, operates only on edges above a certain threshold
to ensure that noise is not emphasized. Care has also been
taken to ensure that edge ringing and undesirable saturation
or hue distortion are avoided.
Chroma transient improvements are needed primarily for sig-
nals that experienced severe chroma bandwidth limitation. For
those types of signals, it is strongly recommended to enable the
CTI block via CTI_EN.
CTI_EN Chroma Transient Improvement Enable,
Address 0x4D[0]
The CTI_EN bit enables the CTI function. If set to 0, the CTI
block is inactive and the chroma transients are left untouched.
Setting CTI_EN to 0 disables the CTI block.
Setting CTI_EN to 1 (default) enables the CTI block.
CTI_AB_EN Chroma Transient Improvement
Alpha Blend Enable, Address 0x4D[1]
The CTI_AB_EN bit enables an alpha-blend function within
the CTI block. If set to 1, the alpha blender mixes the transient
improved chroma with the original signal. The sharpness of the
alpha blending can be configured via the CTI_AB[1:0] bits.
DEMODULATED
CHROMA
SIGNAL
SIGNAL
LUMA
Figure 18. CTI Luma/Chroma Transition
SHARPENED CHROMA
TRANSITION AT THE
OUTPUT OF CTI
LUMA SIGNAL WITH A
TRANSITION, ACCOMPANIED
BY A CHROMA TRANSITION
ORIGINAL, "SLOW" CHROMA
TRANSITION PRIOR TO CTI
Rev. B | Page 34 of 104
For the alpha blender to be active, the CTI block must be
enabled via the CTI_EN bit.
Setting CTI_AB_EN to 0 disables the CTI alpha blender.
Setting CTI_AB_EN to 1 (default) enables the CTI alpha-blend
mixing function.
CTI_AB[1:0] Chroma Transient Improvement Alpha
Blend, Address 0x4D[3:2]
The CTI_AB[1:0] controls the behavior of alpha-blend circuitry
that mixes the sharpened chroma signal with the original one. It
thereby controls the visual impact of CTI on the output data.
For CTI_AB[1:0] to become active, the CTI block must be
enabled via the CTI_EN bit, and the alpha blender must be
switched on via CTI_AB_EN.
Sharp blending maximizes the effect of CTI on the picture, but
can also increase the visual impact of small amplitude, high
frequency chroma noise.
Table 43. CTI_AB Function
CTI_AB[1:0]
00
01
10
11 (default)
CTI_C_TH[7:0] CTI Chroma Threshold, Address
0x4E[7:0]
The CTI_C_TH[7:0] value is an unsigned, 8-bit number speci-
fying how big the amplitude step in a chroma transition is to be
steepened by the CTI block. Programming a small value into
this register causes even smaller edges to be steepened by the
CTI block. Making CTI_C_TH[7:0] a large value causes the
block to only improve large transitions.
The default value for CTI_C_TH[7:0] is 0x08, indicating
the threshold for the chroma edges prior to CTI.
DIGITAL NOISE REDUCTION (DNR)
Digital noise reduction is based on the assumption that high
frequency signals with low amplitude are probably noise and
their removal, therefore, improves picture quality.
DNR_EN Digital Noise Reduction Enable, Address
0x4D[5]
The DNR_EN bit enables the DNR block or bypasses it.
Setting DNR_EN to 0 bypasses DNR (disables it).
Setting DNR_EN to 1 (default) enables digital noise reduction
on the luma data.
Description
Sharpest mixing between sharpened and original
chroma signal.
Sharp mixing.
Smooth mixing.
Smoothest alpha blend function.