The ratio of the power output of an electro-acoustic transducer, under specified conditions, to the power output of an ideal electro-acoustic transducer.

Related Terms


The ratio of the output power delivered to a specified load by an amplifier to the power absorbed by its input circuit.


The ratio of output voltage, current, or power to input voltage, current, or power in electronic instruments


A measure of the power loss of a transducer in transmitting signals, expressed as the ratio of its input power to its output power.


Ratio in a transducer of total output noise power to the portion thereof attributable to thermal noise in the input termination, the total noise being summed over frequencies from zero to infinity, and the noise temperature of the input termination being standard (290 K).


  1. A satellite which contains power source to augment the output signal (i.e., reflected only) as contrasted with ACTIVE SATELLITE; a satellite which is a passive reflector. 2. As defined by the International Telecommunications Union (ITU), an earth satellite intended to transmit radio communication signals by reflection.


An expression of radiation effectiveness, it is the ratio of the power required at the input of a reference antenna to the power supplied to the input of the given antenna to produce, in a given direction, the same field at the same distance. When not specified otherwise, the figure expressing the gain of an antenna refers to the gain in the direction of the radiation main lobe. In services using scattering modes of propagation, the full gain of an antenna may not be realizable in practice and the apparent gain may vary with time.


A device which enables an input signal to control power from a source independent of the signal and thus be capable of delivering an output which is greater than the input signal.


The maximum continuous rated power output as specified on the nameplate and in the technical file of the engine.


  1. An increase in signal magnitude from one point to another, or the process causing this increase. 2. Of a transducer, the scalar ratio of the signal output to the signal input


Equal to the sound power level/heat release. A value used to characterize the amount of combustion noise emitted from a flame. Defined as the ratio of the acoustical power emitted from the flame to the total heat release of the flame. Approximately equal to 1 X 10-6 for premixed and turbulent flames and equal to 1 X 10-9 for diffusion and laminar flames.

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