NR-900S
Operation Manual
8
4. FUNCTION
NR-900S
represents a portable tool that consists of antenna system,
transmitter and two receivers adjusted for double and triple frequency
of the transmitter’s signal.
Two operational modes are available: SEARCH and LISTEN.
In a SEARCH mode the probing signal is converted into a poly-
harmonic one on the radiated nonlinear elements (semi-conductive
items or corroded metal-oxide-metal junction) and retransmitted,
better say – scattered into ambient space.
Retransmitted 2
nd
& 3
rd
harmonics of the probing signal are received
and processed by receivers. Signals strength is indicated by LED bar-
graph display: scales
2
and
3
accordingly. Moreover, it is reproduced
via headphones in the form of interrupted beep-beep audio signal: 1
kHz for the 2
-nd
harmonic and 1.5 kHz for the 3
-rd
one. The audio signal
volume is proportional to the received harmonic signal level.
The receiver inputs switching as well as headphones volume control
is available from the device control panel.
NR-900S
has three output levels for radiated probing signal with 6 dB
step and four levels of the receiver input signal attenuation each of 10
dB. The probing signal output level and receiver input signals
attenuation can be switched over by Control panel buttons. This info
is confirmed by LED display.
An auxiliary
LISTEN
mode is intended for the 2
nd
& 3
rd
harmonic
signals investigation for possible modulation imposed by internal
processes in some active electronic circuits irradiated by the probing
signal generated by NR-900S transmitter.
At that, ‘active’ means the
circuit is in an operational mode carrying out its particular function.
Moreover, this can be done against the existing interference
environment.
It should be noted that Operator should be skilled enough to recognize
such features of retransmitted signals and be familiar with possible
reply of certain targets (electronic & electro-mechanical timers, clocks
or voltage transducers).
