Bilateral comparison of a piezoelectric charge amplifier transfer function inthe range 1 to 10000 Hz

- Piezoelectric transducers used as reference standards are generally of the kind which requires the connection to an high quality charge-amplifier to obtain, from this so called measuring chain, the most stable output signal to be sent to the measuring instrumentation.

- The absolute calibration of the piezoelectric transducer alone (by itself) requires obviuosly calibrating also the charge-amplifier in conditions simulating the connection to the transducer.

- Indirect data on charge amplifier calibration as extracted from previous piezoelectric transducer comparison campaigns often shows rather unjustified amplification scattering which could be due either to poor calibration or to instability of the circulating instrument.

- The proposed comparison will allow to check directly calibration and uncertainties agreement between the two laboratories and to confirm stability of the specific instrument employed.

- The comparison could be extended to other laboratories, using a very stable amplifier, to ascertain their calibration capabilitites and avoiding circulating such an instrumznt in future piezoelectric transducer calibration.

- The calibration technique employs a few standard capacitors (from 1 pF to 1000 pF), connected to the charge-amplifier input, by measuring its output/input voltage ratio and phases when supllying the capacitor with a suitable sinusoidal voltage.

Acoustics, Ultrasound and Vibration (AUV)
Sergio Baggia, INRIM (Italy)
Coordinating Institute
INRIM (Italy)
Participating Partners
PTB (Germany)