FACT SHEET: LASER BASED
LISTENING SYSTEM (LBLS)
When access is not possible, The solution to the problem is our Laser Based
Listening System (LBLS).
This system allows the operator to carry out an undetectable surveillance
operation from outside the building (off-premises). As no installation is
required, you will not even need to enter a building or a room. Normal
conversations within a room create minute vibrations on exterior windows which
act much like the diaphragm of a microphone oscillating with sound waves.
Within a line-of-sight path, the system's tripod-mounted transmitter directs
an invisible beam onto the window, collecting modulated vibrations. This beam
bounces back to an optical receiver which converts the modulated beam into
audio signals. These signals are then filtered, amplified and turned back into
clear conversation. The resulting conversation can be monitored through
headphones and simultaneously recorded for later review.
Successful monitoring requires stable mounting and precise alignment of the
optical receiver. The LBLS is supplied complete with tripod-mounted
transmitter and optical receiver, tape recorder and headphones in a protective
carrying case.
Our LBLS Consists of Three Parts:
* Laser Transmitter
* Laser Receiver
* Amplifier Unit with Audio-Recorder
This system is operated by transmitting an invisible IR-beam to
the window of the target room. The window pane is slightly vibrating in
accordance to the sound waves emanating from speech. The beam is reflected from
the window pane according to the law of optics, ie. the angle of incidence is
equal to the angle of reflection. The receiver picks up the reflected beam that
is modulated by the window pane vibrations, and the optical signals are
automatically converted into electronic signals.
Both the transmitter and the receiver are built into standard single lens reflex
cameras, allowing for perfect concealment.
The complete system is supplied in a camera case incorporating amplifier,
filters and recorder
TRANSMITS/RECORDS:
Sound wave vibrations which reflect off smooth-surface glass
(single or double glass thermo pane). Transmitter laser's angle of incidence
equals the angle of reflection to the receiver. Rippled or grained glass
will not provide a suitable reflecting surface from which to record.
FILTERS OUT:
Acoustic interference cause by interior and exterior sound wave
reflections may be filtered and modulated by the LBMS's receiving system.
The transmission may be fine-tuned by means of a modulated search tone or by
adjusting the placement of the receiver. Tape recordings may be further
edited at the user's option. |
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