Editing Psophometer

[[File:Psophometer IMG 1665.JPG|thumb|Psophometer]]

In [[telecommunications]], a '''psophometer''' is an instrument that measures the perceptible [[noise (signal processing)|noise]] of a telephone circuit.<ref name="Hickman, EW, 2001" />

The core of the meter is based on a [[true RMS voltmeter]], which measures the level of the noise signal. This was used for the first psophometers, in the 1930s.<ref name="IEEE, Psophometer" /> As the human-perceived level of noise is more important for telephony than their raw voltage, a modern psophometer incorporates a weighting network to represent this perception.<ref name="Hickman, EW, 2001" /><ref name="IEEE, Psophometer" /><ref name="CCITT, P53" /> The characteristics of the weighting network depend on the type of [[telecommunication circuit|circuit]] under investigation, such as whether the circuit is used to normal speech standards (300&nbsp;Hz&nbsp;–&nbsp;3.3&nbsp;kHz), or for [[high-fidelity]] [[broadcast-quality]] sound (50&nbsp;Hz&nbsp;–&nbsp;15&nbsp;kHz).<ref name="Hickman, EW, 2001" />

== Etymology ==
The name was coined in the 1930s, on a basis from {{langx|grc|ψόφος|psóphos|noise}}, itself derived from {{langx|grc|ψό||an exclamation of disgust}}.<ref name="OED, Psophometer" /> It is unrelated to {{langx|grc|σοφός|sóphos|wisdom}}.

The '-meter' suffix {{langx|grc|μέτρον|métron|tool for measuring}} was already widely used in English, but also derives originally from Greek.<ref name="OED, Psophometer" />

==See also==
*[[Psophometric voltage]]

==References==
{{Reflist|refs=

<ref name="Hickman, EW, 2001" >{{Cite magazine
  |magazine=[[Electronics World]]
  |date=March 2001
  |author=Ian Hickman
  |title=Balanced circuits
  |pages=190–191
}}</ref>

<ref name="CCITT, P53" >{{Cite book
  |title=Psophometer for use on telephone-type circuits
  |publisher=[[CCITT]]
  |id=Rec. P53 
  |year=1994
  |orig-year=1970
  |url=https://www.itu.int/rec/T-REC-P.53/en
}}</ref>

<ref name="IEEE, Psophometer" >{{Cite journal
  |last1=Harbottle |first1=H.R.
  |date=August 1938
  |title=The circuit noise-meter (psophometer) and its applications
  |journal=[[Journal of the Institution of Electrical Engineers]]
  |volume=83 |issue=500 |pages=261–274
  |doi=10.1049/jiee-1.1938.0142
}}</ref>

<ref name="OED, Psophometer" >{{Cite web
  |title=Psophometer
  |website=[[Oxford English Dictionary]]
  |url=https://en.oxforddictionaries.com/definition/psophometer
|archive-url=https://web.archive.org/web/20171214071552/https://en.oxforddictionaries.com/definition/psophometer
|url-status=dead
|archive-date=December 14, 2017
}}</ref>

}}
*{{FS1037C}}


{{Electrical and electronic measuring equipment}}

[[Category:Electronic test equipment]]
[[Category:Noise (electronics)]]
[[Category:Measuring instruments]]