Program and System Information Protocol

Abbreviation for phase-shift keying.

1. public switched network,
2. packet-switching networks.

An instrument that provides a visual indication of the audible effects of disturbing voltages of various frequencies.
Note: A psophometer usually incorporates a weighting network. The characteristics of the weighting network depend on the type of circuit under investigation, such as whether the circuit is used for high-fidelity music or for normal speech.

Circuit noise voltage measured with a psophometer that includes a CCIF-1951 weighting network.
Note 1: "Psophometric voltage" should not be confused with "psophometric emf," i.e., the emf in a generator or line with 600 internal resistance. For practical purposes, the psophometric emf is twice the corresponding psophometric voltage.
Note 2: Psophometric voltage readings, V, in millivolts, are commonly converted to… (Read More →)

A noise weighting established by the International Consultative Committee for Telephony (CCIF, which became CCITT and, more recently, ITU-T), designated as CCIF-1951 weighting, for use in a noise measuring set or psophometer.
Note: The shape of this characteristic is virtually identical to that of F1A weighting. The psophometer is, however, calibrated with a tone of 800 Hz, 0 dBm, so… (Read More →)

See dBm(psoph), dBm0p.

public switched telephone network

Provider Testing Acceptance

Abbreviation for patch and test facility.