Psophometer

Psophometer

In telecommunications, a psophometer is an instrument that measures the perceptible noise of a telephone circuit.[1]

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.[2] 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.[1][2][3] The characteristics of the weighting network depend on the type of circuit under investigation, such as whether the circuit is used to normal speech standards (300Hz-3.3kHz), or for high-fidelity broadcast-quality sound (50Hz-15kHz).[1]

Etymology

The name was coined in the 1930s, on a basis from Ancient Greek: ψόφος, translit. psóphos, lit. 'noise', itself derived from Ancient Greek: ψό, lit. 'an exclamation of disgust'.[4] It is unrelated to Ancient Greek: σοφός, translit. sóphos, lit. 'wisdom'.

The '-meter' suffix Ancient Greek: μέτρον, translit. métron, lit. 'tool for measuring' was already widely used in English, but also derives originally from Greek.[4]

See also

References

  1. 1 2 3 Ian Hickman (March 2001). "Balanced circuits". Electronics World. pp. 190–191.
  2. 1 2 "The circuit noise-meter (psophometer) and its applications". J. Inst. Electr. Eng. 83 (500): 261–274. August 1938. doi:10.1049/jiee-1.1938.0142.
  3. ↑ Psophometer for use on telephone-type circuits. CCITT. 1994 [1970]. Rec. P53.
  4. 1 2 "Psophometer". Oxford English Dictionary.


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