saa4997h NXP Semiconductors, saa4997h Datasheet - Page 8

• Manufacturer Part Number: saa4997h
• Description: Vertical Reconstruction Ic Veric For Palplus
• Manufacturer: NXP Semiconductors

Philips Semiconductors
FUNCTIONAL DESCRIPTION
Introduction
As shown in Fig.2 the PALplus module consists of two
special integrated circuits:
and four field memories TMS4C2970.
The MACPACIC and the VERIC are intended to generate
digitally decoded 50 Hz YUV signals. The MACPACIC
performs the decompanding function for the helper lines
and the motion adaptive luminance/chrominance
separation. Furthermore, PALplus system controlling,
memory controlling and clock generation are carried out in
this circuit.
The function of the VERIC is to reconstruct the separated
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576 lines frame according the PALplus system description
“REV 2.0” . Chrominance is converted from 430 lines to
576 lines using a vertical sample rate converter.
The data of the VERIC are clocked out with 16 MHz.
The Y : U : V bandwidth ratio is 4 : 1 : 1.
The functional block diagram of the VERIC is shown in
Fig.1. The device consists of 3 main parts:
The input data are delivered by the field memories FM2
and FM3, which include multiplexed first and second field
data processed by the MACPACIC. The luminance and
chrominance input data of the VERIC are clocked with
32 MHz (CLK_32B3). Internally the device operates at
32 or 16 MHz clock frequency.
Luminance processing
In the PALplus encoder the luminance signal is separated
vertically into two sub-bands by a special Quadrature
Mirror Filter (QMF).
A vertical low-pass sub-band consists of the 430 main
letter box lines per frame, and a vertical high-pass
sub-band includes the 144 helper lines per frame.
The used QMF technique has two advantages:
1996 Oct 24
Motion Adaptive Colour Plus And Control IC
(MACPACIC)
VErtical Reconstruction IC (VERIC)
Luminance processing
Chrominance processing
Controlling.
Essentially loss-free data processing
Cancellation of alias components in the main and helper
signal in the decoder.
VErtical Reconstruction IC (VERIC) for
PALplus
72 helper lines and the 430 main lines into a standard
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The luminance vertical conversion process in the decoder
is complementary to that of the encoder.
In the decoder the inverse QMF function is implemented to
recombine the two separated sub-bands and to generate
the original video signal with 576 active lines per frame.
Each output line is calculated from up to seven input lines
stored in line memories containing main or helper
information. The various lines are multiplied by switched
coefficients, changing every line within a sequence of four
lines, depending on the specific mode (CAMERA or FILM).
In case of standard PAL reception, the VERIC is switched
to bypass mode controlled by the signal INTPOL.
For multi-PIP processing the VERIC is also switched to
bypass mode, but controlling of FM2/3 is different (see
Fig.6). The total signal delay between the MACPACIC
input and the VERIC output is one line for this mode.
FM2/3 are driven with 32 MHz clock frequency.
The non-multiplexed input data are clocked out with
16 MHz.
Chrominance processing
The chrominance processing is carried out by the vertical
interpolation filter (poly phase filter).
In CAMERA and FILM mode, intra-field vertical sample
rate conversion is carried out.
One output line is calculated out of three or four lines in
CAMERA or FILM mode using different coefficients or
passed through in bypass mode.
Control functions
The VERIC controller generates the necessary internal
control signals for the line memories, formatters,
reformatters, the selector signals for the multiplexers and
the read signals for the field memories FM2/3.
The system control input signals EVEN_FIELD, INTPOL
and FILM are derived from the control part of the
MACPACIC. The field selection information EVEN_FIELD
is related to the input data of the MACPACIC and is
adapted in the VERIC to its input data.
The control functions are described in Tables 1 and 2.
Table 1 EVEN_FIELD
EVEN_FIELD = 1
EVEN_FIELD = 0
VALUE
even field selected
odd field selected
Preliminary specification
SAA4997H
STATUS