Data Sheet

FFT filter

The FFT ﬁlter feature can be used to ﬁlter out speciﬁc

regions in the FFT spectrum. The FFT ﬁlter array (see

parameters A20…A27) consists of up to 8 indepen-

dent FFT ﬁlters. Further the ± width around these FFT

ﬁlters can be speciﬁed with the parameter D08.

For example: The commands $A20000A<CR>,

$A210032<CR> & $A220050<CR> deﬁne 3 FFT ﬁl-

ters at thebin positions 10, 50&80. The command

$D0802<CR> setsthe±width aroundthe ﬁlters to 2.

This feature allows easy ﬁltering out of un-

wanted constant movements like a ventilator.

Please note that other movements with the

same speed are also ﬁltered out.

Figure 12: FFT ﬁlter and FFT ﬁlter width example