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 10 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 will become visible on a monitor
before the SWF will provide 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 will go low as soon as the input error rate
decreases below the set rate. This response time is
determined by C, as mentioned earlier. A small amount of
hysteris in the comparator ensures noise immunity.
V
DD
15
SYNC
WARNING
CONTROL
COMPARATOR
-
V
DD
6k8
3
+
SYNC
WARNING
FLAG
(SWF)
GS9000C
SYNC
ERROR
Fig. 10 Sync Warning Flag Circuit
CAUTION
ELECTROSTATIC
SENSITIVE DEVICES
DO NOT OPEN PACKAGES OR HANDLE
EXCEPT AT A STATIC-FREE WORKSTATION
REVISION NOTES
DOCUMENT IDENTIFICATION:
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.
Updated values in Electrical Characteristics tables and added test levels
with legend; Updated Figure 8 (Test Set-Up); Changed document from
preliminary data sheet to data sheet; Standardized artwork.
For the latest product information, visit www.gennum.com.
GENNUM JAPAN CORPORATION
C-101, Miyamae Village, 2-10-42 Miyamae, Suginami-ku, Tokyo 168-0081, Japan
Tel. +81 (3) 3334-7700 Fax: +81 (3) 3247-8839
GENNUM UK LIMITED
25 Long Garden Walk, Farnham, Surrey, England GU9 7HX
Tel. +44 (0) 1252 747000 Fax +44 (0) 1252 726523
GENNUM CORPORATION
MAILING ADDRESS:
P.O. Box 489, Stn. A, Burlington, Ontario, Canada L7R 3Y3
Tel. +1 (905) 632-2996 Fax +1 (905) 632-2814
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970 Fraser Drive, Burlington, Ontario, Canada L7L 5P5
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 August 1999 Gennum Corporation.
All rights reserved.
Printed in Canada.
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