Zonge GDP-32 - Page 293

NATURAL SOURCE MAGNETOTELLURICS
Section 13, Page 25 May 2002
Medium Frequency Band
Sample Rate = 256 Hz
Decimation Base Frequency Frequencies
Levels Frequency Interval Obtained
5 .5 Hz 3 - 64 Hz 48, 64 Hz
24, 32
12, 16
6, 8
3, 4
High Frequency Band
Sample Rate = 4096 Hz
Decimation Base Frequency Frequencies
Levels Frequency Interval Obtained
5 8.0 Hz 48 - 1024 Hz 768, 1024 Hz
384, 512
192, 256
96, 128
48, 64
Very High Frequency Band
Sample Rate = 32768 Hz
Decimation Base Frequency Frequencies
Levels Frequency Interval Obtained
5 64 Hz 384 - 8192 Hz 6144, 8192 Hz
3072, 4096
1536, 2048
768, 1024
384, 512
A 5-point digital, low-pass filter is used on the time series for each level of decimation. The
coefficients for this filter are as follows:
a
0
= a
4
= 1.0
a
1
= a
3
= 3.41421356
a
2
= 4.87100924
(From Wight, D.E. and Bostick, F.X., 1980 Proceedings IEEE International Conference on
Acoustic Speech and Signal Processing, April 9-11, 1980, Denver CO. pp 626-629.