Sekotech ST-300 SPIDER, Руководство по эксплуатации, Страница: 19 / 68

OPERATING MANUAL
17
2.5
“
LOW FREQUENCY AMPLIFIER
”
MODE
The “ LOW FREQUENCY AMPLIFIER
”
( “ LFA
”
) mode is intended for the detection of,
– low-frequency signals from hard-wired eavesdropping electronics connected to low-current lines;
– acousto-electric conversion ( “ microphone effect”) involving devices that are connected to low current
circuits in the inspected room.
In the “ LFA
”
mode, signals can be monitored:
– by their graphical representation on the screen (oscillogram or spectrogram);
– by sound (through headphones or speaker).
2.5.1. Main Screen of the “ LFA
”
Mode
The “ LFA
”
mode only becomes available upon connecting the Main Unit with the Electronic Switch.
The mode is accessible from the Start Menu (Fig.18), or from the “ SWITCH
”
mode.
To enter the “ LFA
”
mode from the Start Menum, choose “ LOW FREQUENCY AMPLIFIER
”
using the
and keys, and press “ ENTER”. In the “ LFA
”
mode, two ways of data representation are
implemented, i.e., oscilloscope (Fig.21) and spectrum analyzer (Fig.22). On entering the “ LFA
”
mode, it
is “ OSCILLOSCOPE
”
(Fig.21) by default. To toggle between the two forms of representation, press “ F4
”
.
A spectrogram will appear on the screen. Fig.
22 shows the spectrum analyzer in the ultra low
frequency mode.
In Fig. 22:
1 – current mode
2 – data representation form
3 – frequency marked by the cursor
4 – hairline cursor
5 – signal amplitude at the selected frequency
6 – spectrum analyzer screen
7 – selected gain value
8 – selected bias voltage
9 – hotkey assignment
Fig.22
In Fig. 21:
1 – current mode
2 – data representation form
3 – time scale value (in µs or ms)
4 – measured signal amplitude
5 – vertical scaling of the oscillogram
6 – oscilloscopic screen
7 – selected gain
8 – selected bias voltage
9 – hotkey assignment
The oscillogram can be scaled horizontally with the and keys, and vertically with the
and keys.
To change data representation to “SPECTRUM ANALYZER
”
, press “F4
”
.
The displayed spectrogram (Fig.22) does not scale and spans over the whole range (0-25kHz). It can
be navigated by moving the hairline cursor (4, Fig.22) with the and keys. The current frequency
is always shown numerically above the cursor (3, Fig.22).
To change data representation to (“OSCILLOSCOPE
”
), press “F4
”
.
Fig.21