AK8856VN Datasheet, PDF (17/98 Pages) Asahi Kasei Microsystems – NTSC/PAL Video Decoder

ASAHI KASEI
[AK8856VN]
Functional Outline
(1) Clock
Connect a 27MHz crystal or a 27MHz clock source.
Internal operating clock rates are:
24.5454 MHz for VGA / QVGA / rotated QVGA size / rotated CIF size outputs
27 MHz
for 601 pixel mode, CIF / QCIF
24.5454 MHz clock is generated by an internal PLL.
Although the clock is asynchronous with the input signal, vertical position is aligned since the Digital Pixel
Interpolator is integrated.
(2) Analog Interface
The AK8856 accepts composite video signals.
(3) Input Signal
NTSC-M, PAL-B, -D, -G, -H, -I compatible composite video signals are accepted as input signals.
(4) Analog Input Signal Processing
An anti-aliasing filter is integrated.
PGA
0 dB ~ 12 dB (approximately 0.1 dB / step)
ADC
operates at either 24.5454 MHz or 27.00 MHz
(5) Clamp Processing
Sync-tip clamping is processed in the analog block and digital pedestal clamping is processed in the digital
signal processing block.
(6) Adaptive AGC Function
Based on the difference between the sync-tip level and the pedestal level, the input signal value is corrected
to a proper level.
A video signal level gain adjust function is applied if only the video signal is larger.
(7) ACC Function
Based on the color burst level, the input color signal level is corrected to a proper level.
(8) Y / C Separation Function
Choice of either primary Y / C separation or two dimensional Y / C separation is available.
Mode setting of Y / C separation is done through register settings.
(9) Pixel Interpolator
The AK8856 has an integrated Digital Pixel Interpolator to align the output pixels’ vertical position. No
line-synchronized clock is required.
(10) Picture Quality Adjustment Function
Adjustments of contrast, brightness, color hue and color saturation levels are available.
(11) Output Interface
Outputs are ITU-R BT.601 compatible signal levels (with limit ON / OFF)
Output formats include:
- Camera interface
- ITU-R BT.656-like output*
- Active video region is indicated by HD / VD (FIELD) / DVALID
* With SAV/EAV, 27MHz The number of clocks from EAV to SAV becomes irregular.
MS0522-E-00
17
2006/Dec