User manual

Code: ENIGMA III User Manual
Edition: 1 Revision: 4
Date: 19/12/2008
Page: 25/97
Terminology:
• N represents the width, in samples, of a discrete-time window function. Typically it is an integer
power-of-2, such as 2
10
= 1024.
• n is an integer, with values 0<=n<=N-1. So these are the time-shifted forms of the windows:
w(n)=w
0
(n-(N-1)/2)
,
where w(n) is maximum at n=0.
• Some of these forms have an overall width of N−1, which makes them zero-valued at n=0 and
n=N−1. That sacrifices two data samples for no apparent gain, if the DFT size is N. When that
happens, an alternative approach is to replace N−1 with N in the formula.
• Each figure label includes the corresponding noise equivalent bandwidth metric (B), in units of
DFT bins. As a guideline, windows are divided into two groups on the basis of B. One group
comprises 1<=B<=1.8 , and the other group comprises B>=1.98 . The Gauss and Kaiser windows
are families that span both groups, though only one or two examples of each are shown.
Parameter: ClutterFilter, MaxFilterRange, FFTWindow and InterpolationMode
GAMIC Proprietary