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pulsed oscillator for car speed measurement

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lalukhait

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hi,
I am doing a project of maesuring the car speed and range and using the range,take its sanapshot.Now i m stuck with at creating an oscillator of S-band which produces a pulsed signal for detecting the range as well as measure speed using doppler shift.Any input from you people would be highly appreciated
 

What you should look for is "FMCW" radar system; this can detect both the range and speed, not by pulses, but by swept frequency. Using the pulsed system is also possible but over a short range like in your case, it will be technically difficult.
 

Swept frequency: how would that work? Wouldn't it confuse measuring the doppler shift?
 

From your questions I can see that you never read any radar basics. Start reading a radar textbook, then you can understand.

In short, a CW signal allows to measure the Doppler shift, or, target relative speed. The swept signal allows to detect the target distance. Heard about altimeters?
 

I added radar endorsement to my First Phone 35 years ago.

I can see from your answer that you didn't read the original question. He wants to measure not only distance, but speed as well. You could obtain both with a pulsed CW signal, but I have no idea how, or if, you would do it with a swept signal. Please enlighten me.
 
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The pulsed radar seems to be easy but not over a short range like detecting cars over 20-50 meters.
Try to read how a radar altimeter operates (in airplanes): a swept signal is correlated with the return, an audio (video) beat frequency then corresponds to a distance.
Typical car radars now being introduced alternate FM and CW operation, to get the relative speed as well as the distance.
All radar textbooks describe both systems in detail.
 
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    wa1kij

    wa1kij

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That clears up the mystery. Thank you.
 

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