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Do You Know What a Psophometer Is?

Psophometer used in telecommunication

What is a psophometer?

The term psophometer finds its origin in ancient Greece. There, the word “psóphos” meant as much as noise. Therefore, the synonym – circuit noise-meter – becomes obvious.

With the help of a psophometer, it becomes possible to record and quantitatively evaluate the noise and vibration of electrical or acoustic signals. For the evaluation of noise perception, special signal filters with larger and narrower bandwidths find use. Thus, they enable a weighting of the measured signals.

However, psophometric measurements without a filter exist as well. The measured noise level then refers to the entire frequency range.

The application

The initial challenge that led to the development of a psophometer was to measure the disturbing influence of power induction on telephone calls. Until today, the field of application has hardly changed and so the telecommunications sector still benefits from its invention. The measurement of noise in telephone systems, in broadcasting, in acoustic systems or in other communication systems are typical application examples.

The psophometer plugin from DEWETRON’s OXYGEN

Every OXYGEN installation, starting with version 3.5.1 (here you can find a free trial version of OXYGEN), already includes the psophometer plugin. Please note that an extra license is required for the calculations if you are not using the trial version.

In OXYGEN, psophometer analyses work via online channels (so-called “math channels”). You can simply select any channel (with a sample rate of at least 20 kHz). An additional window allows you to use different frequency weightings. Your measurements can be unweighted or based on weighting options like c-message or flat-filter. In addition to that, a weighting according to the standards from ITU-T O.41 is available as well.

The calculation is based on FFT (you can read more about FFT with DEWETRON’s OXYGEN here). Depending on the sampling rate of the input, the FFT block size is chosen to be 2^N samples while the time window stays between 75 and 125 ms, to ensure passing the detector circuitry tests.


DEWETRON is an Austrian manufacturer of high precision test and measurement technology. In addition to a variety of data acquisition products, DEWETRON also develops its own measurement software called OXYGEN. Apart from psophometer calculations, the analysis software includes numerous other functions such as order analysis, power analysis, FFT and much more.

If you would like to find out more about us, please visit our DEWETRON website. You can also follow our latest updates (e.g. video tutorials, whitepapers and webinars) via LinkedIn and YouTube.


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