Operating instructions HLE 500/5000
15
MAN_HLE500_HLE5000_eng_02
HYDROLUX
®
1800 –
4000 Hz
Fig 13 :
Adjusting the lower filter cut-off frequency
The upper cut-off frequency is adjusted in a similar way,
using the two soft key buttons to the right, underneath
(see fig. 14).
HYDROLUX
®
0 –
70
Hz
Fig 14 :
Adjusting the upper filter cut-off frequency
For the two cut-off frequencies, you can set the 9 frequencies
specified above and can thus easily set the special filter
range for every measurement.
After the filter range has been correctly set, use the soft key
button “ESC” to return to the main menu.
3.6
Filter selection in practice
The decision about the filter settings has to be made by the
user. In general, one can say that, for measurements with
ground microphones, lower frequency ranges should be
chosen. For measurements directly on the pipe or valve
using the sensor rod, higher frequency ranges should be
