This product is listed in: Audio Surveillance Equipment

Laser Microphone

Product number: PKI 3000

  • PKI-3000-Laser-Microphone

    PKI 3000 Laser Microphone

The PKI 3000 Laser Microphone opens up an entirely new dimension of audio surveillance. Our Laser Monitoring System PKI 3100 offers the same opportunity, however, you are always dependent on the laser reflection from the windows to be intercepted as regards the respective angle, i.e. the angle of incidence equals the angle of reflection. Our new PKI 3000 Laser Microphone ensures a considerable independence from angles. The invisible laser beam detects minimum vibrations of objects being induced by people’s conversations. The voice information is transmitted as a frequency modulation of the invisible laser. The surface vibrations are detected in the direction of the laser beam even through a closed window. Noise outside the laser beam does not interfere with the desired monitoring signal so that excellent results are achieved. The audio quality mainly depends on the vibration characteristics of the selected object and on the distance. The detection point is induced to vibrate by the sound waves of the person to be intercepted.

The vibrations generate a Doppler frequency shift in the backscattered laser. This signal is converted into an audio signal by an interferometer with integrated photo detectors and demodulation technology. PKI 3000 is a so-called optical microphone and in contrast to a directional microphone it penetrates almost all glass panes and thus records the conversations of persons to be intercepted in the immediate vicinity. As the laser beam only measures a few millimeters in diameter, target-oriented operation is ensured. PKI 3000 consists of the laser source of protection class 1 and the necessary IR lens with manual fine adjustment. This way, the measuring distance can be chosen between 5 m and max. 150 m. In case of incorrect use, the protection class 1 laser does not provoke eye injuries. The monitor unit converts the optical signal into an audio signal, i.e. the built-in inverter processes the digital data stream into an analog signal for the headset. This is combined with the professional application of a high-quality amplifier with equalizer, dynamic compressor and recording option. Additional dynamic fillers provide for a good intelligibility.

The internal video camera is indispensable for laser beam targeting. As an accessory, video glasses can also be connected. Moreover, the scope of supply includes a stable tripod with fine pan/tilt adjustment. The combination of the visual and acoustic signal allows to quickly select and evaluate suitable objects such as bottles, furniture, vases, TV sets. If the target with optimum acoustic properties is found within a few minutes, nothing then should stand in the way of the desired audio surveillance operation. The used highly sensitive interferometric technology with the invisible laser in the 1550 nm range of course also has its disadvantages and this is the price for the high-tech device PKI 3000. The authority that wants to buy our PKI 3000 should be aware that PKI 3100 and PKI 3200 provide better quality audio signals and PKI 3000 should really only be used where no other audio surveillance possibilities exist.

The PKI 3000 device incorporates the transmitter and receiver as an optical unit, making it easy to set up and target with the integrated, parallax-free camera.

The speech information is extracted from the frequency shift in the backscattered laser light and therefore not dependent on the sureface properties or the intensity of the laser.

PKI 3000 is indispensable for a variety of agencies that rely on high performance surveillance, especially since often extremely delicate conditions make this necessary.

PKI 3000 opens up a completely new field of day and night remote audio surveillance using invisible, eye-safe lasers up to a distance of 300m.

Laser unit
Laser power<10 mW, laser safety IEC/EN60825-1 class 1, eye-safe
Wave length1.550 nm, invisible for the human eye
Characteristics of the detection surfaceAll technical surfaces incl. glass and other solid bodies;
The results depend on the backscatter properties
Current consumptionApprox. 75 W
Supply voltage100 V - 240 VAC +/- 10%, 50/60 Hz, or external 12 V inverter
Measuring distanceFrom 5 m up to 150 m adjustable by manual focusing
TargetingWith built-in low-light 0.1 Lux PAL CCD colour camera with target
Marking with 460 TV lines and 765 x 582 pixels and acoustic
Information via headset
Temperature range+5°C up to +40°C operation
-10°C up to +65°C storage
Protection classIP -40
Weight6 kg
Dimensions400 x 165 x 100 mm incl. objective
Bandwidth settingsWIDE 150 Hz - 7 kHz
BP wide 150 Hz - 3.5 kHz
BP narrow 350 Hz - 3.5 kHz
Off 0 - 7 kHz
Monitor unit
Dimensions225 x 360 x 135 mm
Weight6 kg
SensitivityHigh, medium, low
Display4 lines with backlight
Volume controlVia +/- keys
OutputsLine out: RCA/Cinch filtered audio signal with dynamic compression
Phone3.5 mm TRS filtered audio signal with dynamic compression
Output: 3.5 mm TRS connection (4-pin, audio/video for video glasses (special accessory))
Rear side outputs
S/P-DIF electrical
RCA/Cinch, 48 kSa/s, filtered signal without compression on left and right channel
S/P DIF optical
TOSLINK, 48 kSa/s, filtered signal without compression on left and right channel Velocity
BNC, +/- 5V, raw signal, unfiltered Video BNC, composite video CVBS, 1 Vp-p/75 Ω

Scope of supply:

  • Laser unit
  • Monitor unit with connecting cable, Tripod with gear head
  • 12V / 230V inverter
  • IR inverter board to visualize the laser beam, Carrying case
  • Operating instructions