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Continuous-wave radar (CW radar) is a type of radar system where a known stable frequency continuous wave radio energy is transmitted and then received from any reflecting objects. [1] Individual objects can be detected using the Doppler effect , which causes the received signal to have a different frequency from the transmitted signal ...
Doppler spectrum. Deliberately no units given (but could be dBu and MHz for example). This is an issue only with a particular type of system; the pulse-Doppler radar, which uses the Doppler effect to resolve velocity from the apparent change in frequency caused by targets that have net radial velocities compared to the radar device. Examination ...
The major advantage of pulsed wave Doppler (PW Doppler) over continuous wave (CW Doppler) is that distance information is obtained (time between transmitted and received pulses multiplied by sound velocity equals distance) and gain correction is applied. The disadvantage of pulsed Doppler is that the measurements can suffer from aliasing.
A pulse-Doppler radar is a radar system that determines the range to a target using pulse-timing techniques, and uses the Doppler effect of the returned signal to determine the target object's velocity. It combines the features of pulse radars and continuous-wave radars, which were formerly separate due to the complexity of the electronics.
Pulse-Doppler signal processing begins with samples taken between multiple transmit pulses. Sample strategy expanded for one transmit pulse is shown. Pulse-Doppler begins with coherent pulses transmitted through an antenna or transducer. There is no modulation on the transmit pulse. Each pulse is a perfectly clean slice of a perfect coherent tone.
CW Doppler radar only provides a velocity output as the received signal from the target is compared in frequency with the original signal. Early Doppler radars included CW, but these quickly led to the development of frequency modulated continuous wave radar, which sweeps the transmitter frequency to encode and determine range.
Medium PRF is used with Pulse-Doppler radar, which is required for look-down/shoot-down capability in military systems. Doppler radar return is generally not ambiguous until velocity exceeds the speed of sound. A technique called ambiguity resolution is required to identify true range and speed. Doppler signals fall between 1.5 kHz, and 15 kHz ...
In laser physics and engineering, "continuous wave" or "CW" refers to a laser that produces a continuous output beam, sometimes referred to as "free-running," as opposed to a q-switched, gain-switched or modelocked laser, which has a pulsed output beam. The continuous wave semiconductor laser was invented by Japanese physicist Izuo Hayashi in 1970.