direct wave

direct wave

[də¦rekt ′wāv]
(communications)
A radio wave that is propagated directly through space from transmitter to receiver without being refracted by the ionosphere.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.

direct wave

direct wave
Direct and indirect waves.
An electromagnetic wave that travels directly from a transmitting antenna to the receiving antenna along a straight line. Direct waves are responsible for part, but not all, of the signal propagation between two antennae when a sight line connecting the antennae lies above the ground. The surface (ground) wave and the reflected wave also contribute to the overall signal at the receiving antenna. Also called a line-of-sight wave or a space wave, it is prevalent in frequencies above 30 MHz.
An Illustrated Dictionary of Aviation Copyright © 2005 by The McGraw-Hill Companies, Inc. All rights reserved
References in periodicals archive ?
Their so-called correlation wavefield method looks at the similarities between the signals at two receivers after a major earthquake, rather than the direct wave arrivals.
In Figures 11-14, [S.sub.d] refers to the direct wave signal and [S.sub.r] is the reflected wave signal from the rebar-concrete interface.
By analyzing Figure 3, it is clear that a direct wave can produce scattered waves when it interacts with a hazardous mass different from the dam material.
The pressure of direct wave was measured by PCB pressure sensors in acoustic axis at a distance of 0.877 m from the discharge electrode.
After compensation, the direct wave parts match well and the later reflection parts are different.
This figure shows the case of receiving only a direct wave. When timing synchronization is perfect, their positions are the same of those of data blocks, not overlapping with GIs.
As the amplitude of direct wave [U.sub.0.sup.D] at the generator's node is identical for both the lossless and the lossy case, for a direct comparison with the former case, it is assumed to be equal with [U.sub.0] as in (3).
These spans can be susceptible to failure through fatigue and, as span length increases, the risk of fatigue damage due to direct wave loading or vortex-induced vibrations (VIV) also increases."
The distortion of signals because of the arrival time differences of the direct wave and the reflected wave decreases DF accuracy.
Alternatively, the company has relied on the direct wave receiver that vibrates the entire handset to produce sound.