SYNC WARNING FLAG OPERATION
Each time HSYNC is not correctly detected, the Sync
Warning Flag output (pin 3 ) will go HIGH. The RC network
connected to the Sync Warning Control input (pin 15) sets
the number of sync errors that will cause the SWF pin to go
HIGH. The component values of the RC network shown in
Figure 12 set the SWF error rate to approximately one
HSYNC error in 10 lines. These component values are
chosen for optimum performance of the SWF pin, and
should not be adjusted.
Typically, HSYNC errors become visible on a monitor before
the SWF provides an indication of HSYNC errors. As a
result, the SWF function can be used in applications where
the detection of significant signal degradation is desired.
A high SWF goes low when the input error rate decreases
below the set rate. A small amount of hysteris in the
comparator ensures noise immunity.
V
DD
COMPARATOR
15
SYNC
WARNING
FLAG
-
3
V
DD
SYNC
WARNING
CONTROL
6k8
+
(SWF)
SYNC
ERROR
Fig. 12 Sync Warning Flag Circuit
CAUTION
ELECTROSTATIC
SENSITIVE DEVICES
DO NOT OPEN PACKAGES OR HANDLE
EXCEPT AT A STATIC-FREE WORKSTATION
DOCUMENT IDENTIFICATION
PRELIMINARY DATA SHEET
The product is in a preproduction phase and specifications
are subject to change without notice.
REVISION NOTES:
Added lead-free and green information.
GENNUM JAPAN CORPORATION
Shinjuku Green Tower Building 27F 6-14-1, Nishi Shinjuku Shinjuku-ku,
Tokyo 160-0023 Japan
GENNUM CORPORATION
MAILING ADDRESS:
P.O. Box 489, Stn. A, Burlington, Ontario, Canada L7R 3Y3
Tel. +1 (905) 632-2996 Fax. +1 (905) 632-5946
Tel: +81 (03) 3349-5501 Fax: +81 (03) 3349-5505
GENNUM UK LIMITED
SHIPPING ADDRESS:
970 Fraser Drive, Burlington, Ontario, Canada L7L 5P5
25 Long Garden Walk, Farnham, Surrey, England GU9 7HX
Tel. +44 (0)1252 747 000 Fax +44 (0)1252 726 523
Gennum Corporation assumes no responsibility for the use of any circuits described herein and makes no representations that they are free from patent infringement.
© Copyright May 2000 Gennum Corporation. All rights reserved. Printed in Canada.
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