A Cartesian-coordinate plot of phase shift as the dependent variable, versus frequency as the independent variable.
Note: The phase-frequency characteristic is linear if the phase shift introduced by a circuit or device is the same for all frequencies in the input signal.

Synonym phase distortion.

An electronic circuit that controls an oscillator so that it maintains a constant phase angle relative to a reference signal.
Note: Phase-locked loops are widely used in space communications for coherent carrier tracking and threshold extension, bit synchronization, and symbol synchronization.

1. In digital transmission, angle modulation in which the phase of the carrier is discretely varied in relation either to a reference phase or to the phase of the immediately preceding signal element, in accordance with data being transmitted.
2. In a communications system, the representing of characters, such as bits or quaternary digits, by a shift in the phase… (Read More →)

Synonym phase-shift keying.

A group of antennas in which the relative phases of the respective signals feeding the antennas are varied in such a way that the effective radiation pattern of the array is reinforced in a desired direction and suppressed in undesired directions.
Note 1: The relative amplitudes of--and constructive and destructive interference effects among--the signals radiated by the individual antennas determine… (Read More →)

In facsimile transmission and reception, the process by which the start of the scanning line or lines is made to correspond to one edge of the object being scanned.
Note: If there is no correspondence between the object being scanned and the scanning line or lines, distortion, often in the form of a split image, will occur in the received… (Read More →)

Per-Hop Behavior

In acoustics, a unit of subjective loudness level equal to the sound pressure level in dB compared to that of an equally loud standard sound.
Note: The accepted standard is a 1-kHz pure sine-wave tone or narrowband noise centered at 1 kHz. [From Weik '89]

1. Abbreviation for telephone, telephony.
2. Loosely, the voice-operation mode in radio communications.