What is a digital doppler?
Digital Doppler is a signal processing technique that uses a doppler effect to calculate object speed. Originally, the army developed digital doppler techniques for radars used to monitor, search and light targets. As the cost of digital computer technology has decreased, civilian doppler radar applications have become common, such as the basic role of the Puls-Doppler in the weather forecast. Doppler digital display techniques are also increasingly used in different medical fields.
The Doppler effect is essentially a change in the frequency of the reflection of a reflected goal in motion. The frequency of signal reflected by an object facing an observer will be higher than the frequency of the original signal. The frequency of signal reflected by an object leaving the observer will be lower than the frequency of the original signal. This phenomenon of Doppler shift can be seen how the signal frequency increases or decreases in relation to the original signal over time. Subsequent frequency changes are used forcalculating the speed of the object in relation to the observer.
Computers are used to digitize the collected information because each signal is emitted, reflected and accepted. In its simplest form, Doppler's radar emits an electromagnetic wave to the target. When contacting, the wave is scattered and part of the wave is reflected back to the radar. A computer with a digital doppler receiver sample the reflected wool and calculates the phase shift from the emitted wool and determines the frequency change. The speed of the object can be calculated from the frequency changes, although the range and bearing of the target cannot be determined.
As the speed and size of the computer has improved, it also has the ability to process more information available from the doppler shifts. For example, faster calculations can manage information derived from a quick emissions of microwave pulses instead of a simple signal of a continuous wave. Can be calculated by a pulse delay that bounces the singingt from the target, as well as the strength of the returned signal. This allows you to determine the position and density of the target in conjunction with its relative speed. Typically, these Pulse-Doppler radars scan 360 degrees around the radar at different heights and digital Doppler computers make the assembled data composed.
Weather Doppler uses radar pulse-doppler to study storms and intensity of precipitation. Electromagnetic waves reflect water droplets in the clouds and clotting. Digital Doppler processing can therefore be used to determine the speed and intensity of the upcoming storm system from the speed of cloud movement. The waves reflecting from the thick hail or heavy rain will be strong, while snow and drizzle act more as a sieve, attenuation and Dnarous waves and results in weaker signals. Using an analysis of the pulse time delay, the precise location of the storm and the type of precipitation can be determined.
Computers present information in two types of doppler maps. On the reflectivity map, the colored clotting information is coded by the intensity andThey overlap on a geographical map that indicates a location. The second Doppler map shows the radial speed of the storm that can be used to determine the wind direction. Strong weather systems such as hurricanes, thunderstorms and tornadoes leave signatures on doppler maps, allowing forecasts to issue serious weather warnings.
Innovation of civilian Doppler manufacturer has made their technology practical in the field of medical field. One such application is echocardiographers that test the vascular flow of blood. Similarly, 3D Doppler fetal sonograms gain popularity because they enable parents and doctors to visualize images with a high -resolution moving inside the womb.