"Valiz" <deva8601@uidaho.edu> wrote in message
news:eb2f895.0403230743.4dc19dc@posting.google.com ...[color=blue]
> "Raoul Watson" <WatsonR@IntelligenCIA.com> wrote in message[/color]
news:<TfO7c.520$7F.214@nwrdny03.gnilink.net>...[color=blue][color=green]
> > "Valiz" <deva8601@uidaho.edu> wrote in message
> > news:eb2f895.0403220700.f65cde2@posting.google.com ...[color=darkred]
> > > "Raoul Watson" <WatsonR@IntelligenCIA.com> wrote in message[/color]
> > news:<asP6c.472$GT2.373@nwrdny01.gnilink.net>...[color=darkred]
> > > > "Valiz" <deva8601@uidaho.edu> wrote in message
> > > > news:eb2f895.0403190724.4773fc41@posting.google.co m...
> > > > > "Raoul Watson" <WatsonR@IntelligenCIA.com> wrote in message[/color]
> > news:<app6c.30689$Eg3.17482@nwrdny01.gnilink.net>. ..[color=darkred]
> > > > > > "Valiz" <deva8601@uidaho.edu> wrote in message
> > > > > > news:eb2f895.0403181042.712cad98@posting.google.co m...
> > > > > > > Hi,
> > > > > > > I am updating system time with IRIG time source which sends[/color]
> > irregular[color=darkred]
> > > > > > > pulses as shown below
> > > > > > > 11000011111100111111111111111111....(1-IRIG present and 0-IRIG[/color][/color][/color]
not[color=blue][color=green][color=darkred]
> > > > > > > present)
> > > > > > > I need to update system time when I find a steady pulse or a[/color]
> > series of[color=darkred]
> > > > > > > 1's say for a span of 10-15 seconds. Is there a way to[/color][/color][/color]
implement[color=blue][color=green]
> > this[color=darkred]
> > > > > > > in VB6?
> > > > > > > Thanks in advance.
> > > > > > > Valiz.
> > > > > >
> > > > > > Of course it is doable.
> > > > > > How are you getting the info (serial I/O, WAN. etc.) and which[/color][/color][/color]
IRIG[color=blue][color=green][color=darkred]
> > > > > > (A,B,E,H)?
> > > > >
> > > > > I am using Serial - Com port 17 - Using SaxComm8 OCX and the[/color][/color][/color]
signal is[color=blue][color=green]
> > IRIG-B.[color=darkred]
> > > > > Valiz.
> > > >
> > > > OK.. I wasn't sure, your description certainly does not describe[/color][/color][/color]
IRIG B[color=blue][color=green][color=darkred]
> > > > since the "IRIG present" is merely a flag in the sixth group[/color][/color][/color]
(status)[color=blue][color=green]
> > and[color=darkred]
> > > > it's the opposite of what you have ( 0 = present, 1= not present).
> > > >
> > > > I am not familiar with SaxComm8 ocx but if it can handle the speed[/color]
> > required[color=darkred]
> > > > (IRIG B pulse code consist of one frame with 100 elements.and it all[/color]
> > comes[color=darkred]
> > > > within one second per frame with 10 ms for each element.)
> > > >
> > > > Basically I would read it from the buffer and decode it (first[/color][/color][/color]
element[color=blue][color=green]
> > is[color=darkred]
> > > > seconds, second is minutes, third is hours, fourth is days, etc.[/color][/color][/color]
etc.)[color=blue][color=green][color=darkred]
> > > >
> > > > If you're interested, I have some docs outlining the detail of IRIG[/color]
> > packets.[color=darkred]
> > > > If you want just send me your e-mail address and I'll send it your[/color][/color][/color]
way.[color=blue][color=green][color=darkred]
> > >
> > > Thanks for getting back. At this point I am able to decode the signal
> > > and get the required data but the point is I would like to make sure
> > > it is a series of 1's at the time when I decode. Say, if I want to
> > > update the clock every 10 minutes or say even 10 seconds. I want to
> > > make sure I don't fall on a "0" every time I hit 10 seconds. Any
> > > ideas?
> > > Thanks,
> > > Valiz.[/color]
> >
> > A time code frame begins with a reference marker (this should be your[/color][/color]
goal).[color=blue][color=green]
> > When you need a time reference I suggest you poll for at least 10[/color][/color]
seconds[color=blue][color=green]
> > looking for reference marker. You can also look for a known variable,[/color][/color]
for[color=blue][color=green]
> > example the days or days * 100. When you find this bit combination, do a
> > validation check by checking the previous or next word to ensure that it[/color][/color]
is[color=blue][color=green]
> > not by chance the bit combination exist. If you're polling satellite,[/color][/color]
you[color=blue][color=green]
> > need to make sure you have the receiver locked to at least one satellite
> > (status "0").
> >
> > I'm not sure about the question, if the question is how do you test a
> > certain bit, here is a function that will help you do that:
> >
> > ' Test bit position "bit" in the value "InByte"
> > ' returns true / false
> >
> > Private Function TestBit(ByVal InByte As Byte, ByVal bit As Integer) As
> > Boolean
> > If bit >= 0 And bit <= 7 Then
> > TestBit = ((InByte And (2 ^ bit)) > 0)
> > End If
> > End Function[/color]
>
> Thanks for the info. I am sorry for not being clear with the question.
> I am looking at the Time Quality bit (every second) in the IRIG-B
> signal and it shuffles or toggles back and forth (0 and 1)randomly and
> there's no regularity whatsoever. If it is a "1", an embedded
> microcontroller (Atmel) takes in the signal and from there I update my
> system clock. And, if it is a "0" I need to write system time to the
> microcontroller (which serves as clock for some other serially
> connected devices). My primary concern is that every time I use a
> timer say for 10 seconds to update the system clock, I do not want to
> hit a "0" for every cycle. Although it does not hit every time, there
> is certainly a possibility that I might hit "0". Hence, am looking for
> a method to eliminate that possibility, like for example a sliding
> window that keeps checking for the Time Quality bit status or
> something like that.
> Thanks again for the info.
> Valiz.[/color]
I am afraid I will have to retreat. In all my years I have never heard an
IRIG-B "Time Quality" bit. I am assuming there is something proprietary
about this data so I don't dare to even guess or suggest what you should do.
However, examining the buffer and testing for certain bits as I have outline
in previous e-mail certainly can be used. Good luck.
