training course on weather radar systems - RTC, Regional Training ...
training course on weather radar systems - RTC, Regional Training ...
training course on weather radar systems - RTC, Regional Training ...
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MODULE A- INTRODUCTION TO RADAR<br />
The parts of this block diagram in Figure-2.14. are described below:<br />
Master Clock/Computer: In older <strong>radar</strong>s, this device was called the master clock. It would<br />
generate all of the appropriate signals and send them to the appropriate comp<strong>on</strong>ents of the <strong>radar</strong>.<br />
In modern <strong>radar</strong>s, the functi<strong>on</strong> of the master clock has been taken over by the ubiquitous<br />
computer. Computers now c<strong>on</strong>trol <strong>radar</strong>s just as they c<strong>on</strong>trol many other parts of modern<br />
technology.<br />
Transmitter: The source of the EM radiati<strong>on</strong> emitted by a <strong>radar</strong> is the transmitter. It generates<br />
the high frequency signal which leaves the <strong>radar</strong>’s antenna and goes out into the atmosphere. The<br />
transmitter generates powerful pulses of electromagnetic energy at precise intervals. The<br />
required power is obtained by using a high-power microwave oscillator (such as a magnetr<strong>on</strong>) or<br />
a microwave amplifier (such as a klystr<strong>on</strong>) that is supplied by a low- power RF source.<br />
Modulator: The purpose of modulator is to switch the transmitter <strong>on</strong> and off and to provide the<br />
correct waveform for the transmitted pulse. That is, the modulator tells the transmitter when to<br />
transmit and for what durati<strong>on</strong>.<br />
Waveguide: Figure 1.2.6 shows that the c<strong>on</strong>necting the transmitter and the antenna is<br />
waveguide. This is usually a hollow, rectangular, metal c<strong>on</strong>ductor whose interior dimensi<strong>on</strong>s<br />
depend up<strong>on</strong> the wavelength of the signals being carried. Waveguide is put together much like<br />
the copper plumbing in a house. L<strong>on</strong>g piece of waveguide are c<strong>on</strong>nected together by special<br />
joints to c<strong>on</strong>nect the transmitter/receiver and the antenna.<br />
Antenna: The antennas are the device which sends the <strong>radar</strong>’s signal into atmosphere. Most<br />
antennas used with <strong>radar</strong>s are directi<strong>on</strong>al; that is, they focus the energy into a particular directi<strong>on</strong><br />
and not other directi<strong>on</strong>s. An antenna that sends radiati<strong>on</strong> equally in all directi<strong>on</strong>s is called<br />
isotropic antenna.<br />
Receiver: The receiver is designed to detect and amplify the very weak signals received by<br />
antenna. Radar receivers must be of very high quality because the signals that are detected are<br />
often very weak.<br />
24<br />
TURKEY RADAR TRAINING 1.0 / ALANYA 2005