AK8853XQ Datasheet, PDF (17/70 Pages) Asahi Kasei Microsystems – NTSC/PAL/SECAM Digital Video Decoder

[AK8853XQ/ VN]
7. Functional description
7.1 Analog interface
The AK8853 accepts composite video signal (CVBS) input, with 4 input pins available for this purpose.
The decode signal is selected via the register.
INSEL[1:0]-bits
[00]
[01]
[10]
[11]
Input channel selection
AIN1
AIN2
AIN3
AIN4
Notes
7.2 Analog band limiting filter and analog clamp circuit
7.2.1 Analog band limiting filter
The characteristics of the AK8853 internal analog band limiting filter (anti-aliasing), which is in front of
the AD converter input, are as follows:
±1dB (~6MHz )
−22dB (27MHz)….Typical value
7.2.2 Analog clamp circuit
The analog circuit of the AK8853 clamps the input signal to the sync tip (analog sync tip clamp). The
clamp timing pulse, with its origin at the falling edge of the internally synchronized and separated sync
signal, is generated at approximately the central position of the sync signal. Its digital circuit clamps the
digitized input data to the pedestal level (digital pedestal clamp), as described in Sec. 7.20 below.
7.3 Input video signal categorization
The AK8853 can decode the following video signals, in accordance with the register setting.
NTSC-M,J
NTSC-4.43
PAL-B,D,G,H,I,N
PAL-Nc
PAL-M
PAL-60
SECAM
In auto detection mode, it automatically recognizes the input signal category, from among the above.
Rev-E-00
17
2008/01