ULTRA HIGH FREQUENCY

Radio frequency of 300 to 3,000 megahertz.

ultra_high_frequency radio frequency

Related Terms

DIRECTIVITY FACTOR

The ratio of radiated sound intensity at a remote point on the principal axis of a loudspeaker or other transducer, to the average intensity of the sound transmitted through a sphere passing through the remote point and concentric with the transducer; the frequency must be stated.
The ratio of the square of the voltage produced by sound waves arriving parallel to the principal axis of a microphone or other receiving transducer, to the mean square of the voltage that would be produced if sound waves having the same frequency and mean-square pressure were arriving simultaneously from all directions with random phase; the frequency must be stated.

sound square ratio point principal average sphere pressure directivity_factor frequency voltage mean parallel axis

A frequency domain stability test for systems consisting of a linear component described by a transfer function preceded by a nonlinear component characterized by an input-output function), with a unity gain feedback loop surrounding the series connection.

popov's_stability_criterion test feedback_loop gain loop frequency frequency_domain stability transfer domain linear

POLE-ZERO CONFIGURATION

A plot of the poles and zeros of a transfer function in the complex plane; used to study the stability of a system, its natural motion, its frequency response, and its transient response.

pole-zero_configuration plot frequency study stability transfer

PIEZOELECTRIC ELEMENT

A piezoelectric crystal used in an electric circuit, for example, as a transducer to convert mechanical or acoustical piezoelectric element piezoelectric gage signals to electric signals, or to control the frequency of a crystal oscillator.

piezoelectric_element transducer electric piezoelectric_element frequency mechanical piezoelectric_gage element crystal

PHOTOELECTRIC CONSTANT

The ratio of the frequency of radiation causing emission of photoelectrons to the voltage corresponding to the energy absorbed by a photoelectron; equal to Planck's constant divided by the electron charge.

photoelectric_constant constant frequency ratio electron radiation emission voltage energy

PENDULUM ANEMOMETER

A pressure-plate anemometer consisting of a plate which is free to swing about a horizontal axis in its own plane above its center of gravity; the angular deflection of the plate is a function of the wind speed; this instrument is not used for station measurements because of the false reading which results when the frequency of the wind gusts and the natural frequency of the swinging plate coincide.

pendulum_anemometer plate deflection horizontal station plane wind natural_frequency axis frequency anemometer center swing

PASSBAND

A frequency band in which the attenuation of a filter is essentially zero.

passband filter frequency attenuation frequency_band band

PARAMETRIC EQUALIZER

[ENG ACOUS] A device that allows control over the center frequencies, bandwidths, and amplitudes (parameters) of band-pass filters that determine the frequency response of audio equipment.

parametric_equalizer frequency_response frequency center device control

OVERTONE

One of the normal modes of vibration of a vibrating system whose frequency is greater than that of the fundamental mode.

overtone frequency system vibration normal

OPTICALLY PUMPED MAGNETOMETER

A type of magnetometer that measures total magnetic field intensity by observation of the precession frequency of magnetic atoms, usually gaseous rubidium, cesium, or helium, which are magnetized by irradiation with circularly polarized light of a suitable wavelength.

optically_pumped_magnetometer magnetic magnetic_field frequency irradiation field total light precession magnetometer