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Resonance:
Reinforcement and prolongation of a sound or musical tone by reflection
or by sympathetic vibration of other bodies.
Superheterodyne
Receiver :
Donating a device or method of radio reception in which beats
are produced by superimposing a locally generated radio wave on
an incoming wave. In the superheterodyne receiver the intermediate
frequency is amplified and demodulated.
Tone
Burst Generators In Research
Tone burst generators are often used in high power ultrasonic
applications. Modern computer controlled ultrasonic instrumentation,
such as Ritec's RAM 10000, is a complete advanced measurement
system designed to satisfy the needs of the acoustic researcher
in materials science or advanced NDE. Its purpose is to transmit
bursts of acoustic energy into a test piece, receive signals from
the piece following this burst, then manipulate and analyze these
received signals in various ways. Extreme versatility is achieved
through a modular approach allowing an instrument to be configured
for unique applications not previously encountered. Unwanted modules
need not be purchased and in many cases special modules can be
designed and constructed.
The high power radio frequency (RF) burst capability allows researchers
to work with difficult, highly attenuative materials or inefficient
transducers such as EMATs.
A computer interface makes it possible for the system to make
high speed complex measurements, such as those involving multiple
frequencies. Many of these measurements are very limited or impossible
with manually controlled instruments. A Windows or DOS based personal
computer controls and acquires data from the system. Software
is supplied with each RAM-10000 suitable for a wide variety of
applications including those involving EMATs, acoustic resonance,
velocity, relative velocity, and attenuation measurements. In
addition, the source code for this software is made available
so that it may be modified to include new applications or changes
in technique.
The unique automatic tracking superheterodyne
receiver, quadrature phase sensitive detection circuits and
gated integrators offer superb analog signal processing capability.
Both the real and imaginary parts of the value of the Fourier
transform at the driving frequency are obtained. This increases
the dynamic range of the instrumentation and allows phase and
amplitude information at the driving frequency to be extracted
from noise and out-of-band spurious signals more efficiently than
using Fast Fourier Transform (FFT) techniques.
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