Convert 15KHz to 30KHz?

["Bryan Parkoff" <bryan.nospam.parkoff@nospam.com>]

    I have seen that someone tried to convert 15KHz horizontial sync to
30KHz horizontial sync from Apple IIgs' RGB to VGA monitor.  The trick is to
add blanking sync.  First line is displayed, second line is blanking, third
line is displayed, four line is blanking, and so forth until it reaches 400
lines.  It is like that displaying is odd and blanking is even.
    The convertor device receives 15KHz from Apple IIgs' RGB before it adds
another 15KHz as blanking.  It equals to 30KHz before it starts to display
on VGA monitor.  I am sure that mixing odd and even lines do not look good.
Someone did try to duplicate odd lines into even lines that is called double
line per single line.  It may be a clever trick, but it is very rare that no
one is doing a test yet.
    Did you test to work with LCD that supports 15KHz?

-- 
Bryan Parkoff