Radar Systems - Pulse Radar

The Radar, which operates with pulse signal for detecting stationary targets is called Basic Pulse Radar or simply, Pulse Radar. In this chapter, let us discuss the working of Pulse Radar.

Block Diagram of Pulse Radar

Pulse Radar uses single Antenna for both transmitting and receiving of signals with the help of Duplexer. Following is the block diagram of Pulse Radar −

Let us now see the function of each block of Pulse Radar −

Pulse Modulator − It produces a pulse-modulated signal and it is appped to the Transmitter.

Transmitter − It transmits the pulse-modulated signal, which is a train of repetitive pulses.

Duplexer − It is a microwave switch, which connects the Antenna to both transmitter section and receiver section alternately. Antenna transmits the pulse-modulated signal, when the duplexer connects the Antenna to the transmitter. Similarly, the signal, which is received by Antenna will be given to Low Noise RF Amppfier, when the duplexer connects the Antenna to Low Noise RF Amppfier.

Low Noise RF Amppfier − It amppfies the weak RF signal, which is received by Antenna. The output of this amppfier is connected to Mixer.

Local Oscillator − It produces a signal having stable frequency. The output of Local Oscillator is connected to Mixer.

Mixer − We know that Mixer can produce both sum and difference of the frequencies that are appped to it. Among which, the difference of the frequencies will be of Intermediate Frequency (IF) type.

IF Amppfier − IF amppfier amppfies the Intermediate Frequency (IF) signal. The IF amppfier shown in the figure allows only the Intermediate Frequency, which is obtained from Mixer and amppfies it. It improves the Signal to Noise Ratio at output.

Detector − It demodulates the signal, which is obtained at the output of the IF Amppfier.

Video Amppfier − As the name suggests, it amppfies the video signal, which is obtained at the output of detector.

Display − In general, it displays the amppfied video signal on CRT screen.

In this chapter, we discussed how the Pulse Radar works and how it is useful for detecting stationary targets. In our subsequent chapters, we will discuss the Radars, which are useful for detecting non-stationary targets.