Hello Folks;

Please bear with me here I know you do not like to hear this
but it will help me decide how to finish my program.

I am rewriting my recording and display programs
to use 12 bits instead of 8 to avoid saturation problems.
In my display program I create a PSN4 file to be able to
read times in winquake and share with the rest of you.
I am having problems getting WINQUAKE to properly
show the time of the very first sample since
MY first sample can be something OTHER than
an exact second and usually has a fraction.

There are two Items in the header that affect time readings
And I'm wondering how to properly use them.

WINQUAKE TYPE4 HEADER DATA
GIVEN: FIRST SAMPLE TIME 00:00:35.151
       Hour?    == 00  byte value 0 to 23
       Minute?  == 00  byte value 0 to 59
       Seconds? == 35  byte value 0 to 59
       SPACE HOLDER?   byte value 0
       NANOseconds&    LONG signed integer value 4 bytes low endean
       0 to 999,999,999
       OFFSETseconds#  DOUBLE floating point value  8 bytes IEEE


Find: What is the proper way to indicate
      the fractional value which remains ?

A. Put the fraction 0.151 into the nanoseconds variable times one billion
B. Put the fraction 0.151 into the offset area following the nanoseconds area
C. CROP the recorded DATA to start at an exact second
D. THERE IS NO WAY TO GET THE FIRST SAMPLE TO SHOW THE PROPER FRACTIONAL VALUE

What's the best answer here ?

I know if I crop the file to an exact cal mark second
I get pretty good fractional times. I am guessing
this may be the best way to go since I may be using
WQ in ways it was not designed to be used.
This will mean saving 4 minutes of modulo history
instead of three. I do not want to do this
unless absolutely necessary.

When I look at my own data I will assign
discreet date-times UTC to each sample
relative to a given calibration mark
and not guess between samples.
The cal sample happens at the transition
between second 59 and second zero the first
sample after this event and I call that the
exact second and calculate all other sample times
from that one reference point.
WINQUAKE works different, possibly better,
I just need to understand it better.
The times I use are in the WINQUAKE "?"
type relating to synchronization with WWV
radio broadcast.

Thanks for answers,
geoff

ps, I have found lots of errors in my older program
leading to not so good time readings in the past.
Every time I do this, the results seem better
than before.
But now I'm reaching the point of diminishing returns.


__________________________________________________________

Public Seismic Network Mailing List (PSN-L)