Rudner raised an objection that would find multiple echoes in the literature: if a work such as Beethoven's Fifth Symphony is an abstract entity, this would have "as a counter-intuitive consequence a denial that Beethoven created the Fifth Symphony" (1950, 385).
Vocal phrases were repeated and subjected to multiple echoes, panned across the stereophonic sound outlets.
But in short distance ranging applications especially in the space-limited fields, there usually exists strong multiple echoes which will decline the distance measurement accuracy seriously.
Multiple echoes recorded on ionograms are the signature of these irregularities in the ionograms, usually called Spread-F.
LiDAR manufacturers have attempted to reduce this influence with multi-return and waveform LiDAR, which are capable of either identifying multiple echoes per laser pulse, or recording the entire waveform that may be post-processed to the same effect.
However, when the distance between the transmitter and receiver is limited, the received signal can be polluted by strong multiple echoes, which can significantly degrade temperature accuracy.
The improvement in bandwidth is largely due to progress in signal-processing software, which is capable of coping, for example, with multiple echoes of a signal from a choppy surface.
The return signal detected by a fish finder is a combination of multiple echoes.
In addition the difficulties with various intense noise fields, there difficulties with multi-path and multiple echoes.
In general, these applications do not require high resolution performance, but it is necessary to assure high system reliability also within critical scenarios, as in the case of partially transparent atmosphere or environment in presence of multiple objects (implying multiple echoes having different delay times).
