psophometer
A psophometer is a noise voltmeter. Psophometric measurements can be performed without filters, in which case the measured noise level refers to the entire frequency range.
For the evaluation of noise perception, there are special weighting filters with wider and narrower bandwidths with which the noise in telephone systems, broadcasting, acoustic systems or other communication systems can be measured, evaluated and weighted. The CCIR and the ITU-T have specified corresponding weighting filters.
The RMS voltage of the noise is measured and displayed on a pointer instrument or on a digital display in decibels. Since psophometers are used in various communication systems, they have switchable impedances for optimal matching.
Measurement and weighting with a psophometer is in decibels( dB) and is denoted by dBm(psoph). The reference level is dBm0p.