Fine dust

A significant disadvantage of velocity sensors (Geophone) provided by the manufacturers of most of the other SBR-vibration meters used is their resonance peak (= own opslinger frequency of the mass-spring system) of about 6 to 12 Hz. This is precisely where vibrations occur in the environment and can cause many problems. The standards for these low frequencies are too strict, and they use a phase rotation, instead of the signal. Some manufacturers claim the resonant rise and phase distortion electronically compensate through the installation of an electronic "signature" in each Geophone. In practice, however, this is not electronically accurate, and delivers an inaccurate solution to the problem.

Another disadvantage of the Geophone is its sensitivity, which can lead to problems in accuracy if it falls or is dropped. Such an impact can change the response of the Geophone. This fact is rarely detected in the field.

In addition to the (mostly unknown) measurement error of the sensor / Geophone, according to a study of different instruments, it has also detected a measuring range of about 25% where the accuracy is another 10%. (See collaborative study of the province of North Brabant http://www.abcgeluid.nl/trillingsmeter-sbr.)

The measurement inaccuracy is considerable. This spread, in combination with a variety of other systematic errors that occur, by definition, in the measurements and the above-mentioned problems in the use of Geophones, ensure that the probability of drawing a false conclusion (in the field) is high.

The AuroVibe has  resolved these problems by using a modern tri-axial planarhear piezoelectric accelerometers with temperature monitoring. This sensor is completely sealed in stainless steel housing and protected against bumps, drops and throwing to 200 g (12.4 cubic foot). The high-quality ceramics of this sensor provides a pure, stable measurement for many years, with a completely flat frequency response in range without electronic corrections and annoying phase distortions.

Figure 1: Typical response of the acceleration sensor.

typical low frequency response, AuroVibe

typical low frequency response, aurovibe