OPERATING MANUAL
32
2.5. Listening (AUDIO mode)
The AUDIO mode is primarily intended for analysing target responses by listening to the
demodulated signal output. This should give the operator ample information to identify the
response type.
To switch from SEARCH to AUDIO, press
. The SEARCH led (5, Fig. 4) on the antenna
head will then go off, and AUDIO led will light up (6, Fig. 4).
When the AUDIO mode is on, the device status will be displayed on the antenna module as
described in Table 2 below.
Table 2
*Upon switching to AUDIO, none of the TUNING bar segments are lit, which corresponds
to #0 frequency combination.
The ST 40
2
Cayman NLJD makes it possible to listen to demodulated signals while probing
with six different frequency combinations. Each combination, indicated by LEDs on the TUNING
bar, is suited to deal with a particular category of nonlinear objects. Upon activation of the AUDIO
mode, frequency combination #0 is set by default; it is meant for probing semiconductor content
and, as a rule, gives good results in identifying active radio-transmitting and sound-recording
devices.
Frequency combination #1 is used to analyse return signals from MOM (metal/oxide/metal)
structures.
The remaining four combinations are auxiliary. Their use is advised when responses have been
observed in the SEARCH mode on the red INPUT LEVEL bar, yet probing with combination #0
has rendered no definitive findings.
Table 3 shows correspondence between frequency combinations and responses observed in
the SEARCH mode.
legend
colour
light indication
meaning
POWER
red
continuous
The antenna module is powered properly.
blinking
The battery is discharged and needs to be
replaced.
TUNING
yellow
continuous*
The 5-segment bar displays the selected
probing frequency combination.
AUDIO
yellow
continuous
AUDIO mode on.
INPUT
LEVEL 3
white
varying numbers of
lit LEDs
The 16-segment bar displays the levels
of returned signals. Note: in the AUDIO
mode this gauge bar shows a sum total of
responses, regardless of their type.
