GS1881-CDA Gennum Corporation, GS1881-CDA Datasheet - Page 14

• Manufacturer Part Number: GS1881-CDA
• Description: Monolithic Video SYNC Separators
• Manufacturer: Gennum Corporation

VERTICAL SYNC OUTPUT
520 - 23 - 03
VERTICAL SYNC OUTPUT
HORIZONTAL OUTPUT
Gennum Corporation assumes no responsibility for the use of any circuits described herein and makes no representations that they are free from patent infringement.
(3) Deriving Odd/Even Using the GS4981
Odd/even field information can be derived using the vertical
and horizontal outputs from the GS4981 along with an external
positive edge D flip/flop. The horizontal output is used
as the D input and the vertical output as the clock, as
shown in Figure 27.
REVISION NOTES
The only change from 520-23-02 to 520-23-03 is that the document has been
upgraded to a full DATA SHEET. It is no longer Preliminary.
ODD/EVEN OUTPUT
ODD/EVEN OUTPUT
VIDEO INPUT
COMPOSITE
HORIZONTAL
VIDEO INPUT
COMPOSITE
GS4981
GS4981
GS4981
GS4981
START OF ODD FIELD
START OF EVEN FIELD
SYNC OUTPUT
SYNC OUTPUT
VIDEO INPUT
COMPOSITE
COMPOSITE
VERTICAL
525
263
1
264
0.1µF
2
Fig. 27 Derivation of Odd/Even with GS4981
2
3
4
1
Fig. 28 Timing Diagram
265
GS4981
3
8
6
5
7
266
14
680k
0.1µF
© Copyright March 1991 Gennum Corporation.
At the start of an odd field the vertical output ends in the middle
of the horizontal line and a high will be latched. At the start of
an even field, the vertical output ends near the beginning of
the horizontal line and since the horizontal output is low, a low
will be latched. This timing sequence is shown in Figure 28.
4
267
HORIZONTAL
BACK PORCH
V
R SET
OUTPUT
CC
5
DOCUMENT
IDENTIFICATION
PRODUCT PROPOSAL
This data has been compiled for market investigation purposes
only, and does not constitute an offer for sale.
ADVANCE INFORMATION NOTE
This product is in development phase and specifications are
subject to change without notice. Gennum reserves the right to
remove the product at any time. Listing the product does not
constitute an offer for sale.
PRELIMINARY
The product is in a preproduction phase and specifications are
subject to change without notice.
DATA SHEET
The product is in production. Gennum reserves the right to
make changes at any time to improve reliability, function or
design, in order to provide the best product possible.
5 - 12V
268
6
269
D FLIP/FLOP
All rights reserved.
D
CLK
7
Q
Q
270
ODD/EVEN
OUTPUT
Printed in Canada.
8