Return signal

Elastic scattering is also the basis for Hdar, in which a laser pulse is propagated into a telescope s field of view, and the return signal is collected for detection and in some cases spectral analysis (14,196). The azimuth and elevation of the scatterers (from the orientation of the telescope), their column density (from the intensity), range (from the temporal delay), and velocity (from Doppler shifts) can be deterrnined. Such accurate, rapid three-dimensional spatial information about target species is useful in monitoring air mass movements and plume transport, and for tracking aerosols and pollutants (197). 

In the second technique, the flowing liquid must contain scatters in the form of particles or bubbles that will reflect the sound waves. These scatters should be travehng at the velocity of the hquid. A Doppler method is applied by transmitting sound waves along the flow path and measuring the frequency shift in the returned signal from the scatters in the process fluid. This frequency shift is proportional to liquid velocity. 

The superposition principle allows us to assume just a single scatterer in the view of the radar. The transmitted signal hits this scatterer whose distance (we measure distance and time in the same units) from the (collocated) transmitter and receiver is r. Assume that the scatterer is stationary. The return signal will be a delayed version of the original, delayed by the total round trip time from the radar to the scatterer. Specifically the signal voltage at the antenna of the receiver is... 

In the receiver some noise is added ( receiver noise ), arising from thermal activity generated within the components of the receiver. For distant scatterers the return signal is often so weak that this thermal noise can become a significant issue. We write... 

Now we consider the possibility that the target is moving relative to the radar. The scattered waveform is modified by the Doppler effect. If this is done correctly it results in a time dilation of the return signal, so that, if the target has a radial velocity v, the return signal su(t) becomes... 

An operation is a subtype of an action operations are actions consisting of an invocation from a sender to a receiver, followed by an activity on the part of the receiver and possibly ending with a return signal to the sender. Operations are a one-sided view of the sender-receiver interaction. 

FMCW radar level gauges are the primary tank farm radar devices because of the inherent accuracy. Pulse transmitters are not suitable for tank farm inventory and custody transfer applications. The combination of foam and low-dielectric material can cause errors or provide an insufficient signal strength on the return signal. 

There may be other solutions of the problem at hand. The system thus asks whether we are satisfied with the solution just given or whether it should try to find alternate solutions. In some implementations the system poses the respective question explicitly, awaiting a specified response (generally yes or no). Other systems just wait for the user to act. The convention in these systems is often that a carriage return signals accepting the solution, where as input of a indicates that alternate solutions are to be found. In the present case, there are no other solutions. Thus, if we ask for more we get the answer no. Another interesting question may be... 

The Teramobile container also includes a Lidar detection chain based on a 40 cm receiving telescope, a high-resolution spectrometer equipped with a set of gratings and detectors allowing simultaneous temporal and spectral analysis of the return signal in a wavelength range between 190 nm and 2.5 pm. 

The backscattered signal from aerosol particles is attenuated by traveling (twice) through the air, and this attenuation must be considered in quantitative retrievals. As an optical technique, lidar relies on the optical properties of the aerosol particles, which are generally not known and must be assumed. The difficulty arises because the returned signal is proportional to the backscatter... 

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