Experimental Log: Roger Bland, November 25, 2001
Matched Filtering for RAFOS Sources (continuing()
( logbook | ifremer on RAFOS |Garfield at NPS )
Today I hope to determine the correct function to fit the RAFOS signals. I am working with one signal which is large enough to determine some details of its shape. The signal is SS1 from day 245, starting at about 4:34:58Z and ending at 4:36:17Z. The files involved are:

Now I will make a special file with the same 90-sec bite of data, but without mixing or downsampling: s1245b.dat. The start time will be 4:34:50Z = 0.190856481 d, or point number 599319. The segment selected is thus idat(599319:689318). The file contains: npt (long) = 90,000, yd(npt) (double), websig(npt) (float).

I have finished a good attack on this problem. I found a good match to the data with a linear sweep based on the following parameters (see program):

The equation used to calculate the replica is
r(t) = sin f(t), t1 < t < t1+T
r(t) = 0 otherwise
w(t) = w1 + W/T * (t - t1)
f(t) = f1 + w1 t + 1/2 (W/T) (t-t1)2