Products | Systems Division


UEP and ELFE sensors & amplifiers

The Polyamp Carbon Fiber Electrodes sensor is very sensitive. The mechanical robustness, handling and longevity of carbon fiber technology sensors make it much more versatile for underwater UEP / ELFE applications compared to electrode type of sensors.  Compared to AgAgCl sensors the stabilisation of sensitivity at deployment is much faster than electrode type of sensors. Making them especially suitable for fast deployable systems (Mines, ROV, signature check before entering mine affacted areas).

Carbon fiber sensor is in fact very sensitive and its noise is lower than the very low noise PA3004 amplifier.  1 nV/m(RoothHz) (5 mHz to 5 kHz)(1). 

In differential versus low-ohmic measurements, the property of sensor is capacitive, which means a virtual DC voltage will occur. For this reason, the amplifier is equipped with a high pass filter (HP 5 mHz) to provide a stable zero level. This HP filter also protects from amplifier saturation, due to DC noise, which is the most common cause of saturation on all types of highly sensitive amplifiers. Therefore, this HP filter is also particularly relevant to the AgAgCl system.

(1) ULF actually 0 - 3 Hz by definition. Our CF-sensor is not usable for passive geological applications, although Earth quakes can be detected.

UEP Sensor Data
Sensor type



Length 125±5 mm 58 mm
Diameter 50 mm 55 mm
Weight in Air 150 g 130 g
Weight in Water 10 g 10 g
Standard cable  100 cm 100 cm
Optional cable 1 pole ILM1M connector 1 pole ILM1M connector
Optional cable length Up to TBD meter Up to TBD meter

The very low noise differential amplifier PA3004

The PA3004 amplifier meets the demand for underwater platform integration with flexibility for different type of measurements. PA3004 is optimized for both our carbon fiber type sensors and AgAgCl electrodes. The very wide bandwidth meets the definition ELFE frequency of 0-3000 Hz. However, even in the case of measurements near the field, very rarely usable frequencies above 500 Hz are detected. It emphasizes for signal analysis, that is actually sensitivity and noise levels at frequencies below 500 Hz that are used.

Important functions of the amplifier
  • Optimized input for Carbon fiber or AgAgCl sensors by switch setting
  • Particularly useful for integration into an underwater platform
  • Very low noise with +80 / 86 dB gain
  • Signal level 1 nV RootHz @ 1 to 3000 Hz
  • Linearity <1% 1 to 5000 Hz
  • Selectable +80/+60 dB gain with relay (-15V)
  • Insulation amplifiers provide excellent signal separation and common mode noise suppression
  • Up to 4 km analog signal transmission with a line driver.