Pulse Radar system block diagram

 Pulse radar system has a rectangular pulse of high power which is used in detection and other functions. 

Following are the major parts of pulse radar system.-

• Trigger source - The trigger source makes the pulse available to the modulator.  The radar prefers a flat off rectangular pulse.  Because it adjusts the amplitude, time period and repeat rate.  Which is the factor required to specify and calculate the performance of the radar system.
• Modulator - The modulator provides a rectangular voltage pulse to the output tube with the help of the supply voltage.  This voltage provider also has an on / off switch which we can use as per our requirement.  Mainly two types of modulators are used which are as follows -

1. Line pulsing modulator - is also called hard tube modulator. The advantage of this modulator is that it is simple, compact, inexpensive, and useful, but the pulse changes when different lengths of pulses are required. This modulator is not used in radar systems, but radar requires variable pulse width.
2. Active Switch Modulator - This system provides high-level modulation to the output tube. This system is less useful and more bulky than a line modulator, but this system easily achieves variable width pulse widths. This modulator is mostly used in practice

• Output tube -  This output tube is a magnetron oscillator or amplifier such as a klystron, traveling wave tube or cross field amplifier.  Selection of any of these depends on the specific requirement of the system.  If the radar is of low power, then IMPATT, gun oscillator or TRAPATT amplifier are used. The radar transmitter consists of an output tube, trigger source and a modulator. The main function of this transmitter is to generate a low frequency frequency in high power. It uses less power transmitters than the C-band.
• ATR switch, TR Switch, DUPLEXER - It controls the transmitting and receiving signals.  This system connects the receiver to the antenna at a suitable time.  This protects the receiver from high power transmitters.  Which is possible with the help of a duplexer.  The duplexer has a fast functioning radio frequency switch.  Called the transmitter receiver (TR) switch and an anti-transmitter receiver (ATR) switch which is used by the power of the transmitted pulse and these switches protect the delicate, sensitive and radar receiver from the high power pulses of the transmitter .  The ATR switch is a TR switch that does not have output leads.  A. R. T.  The switch acts as a short circuit load impedance or open circuit load impedance.
• Receiver - The receiver of the radar is a UHF or microwave receiver of high sensitivity with noise figure is the lowest and the band width is very high.  It usually uses a super heterodyne type receiver that can also detect 10–12 watts of micro power.  It detects the designer echo signal in the presence of receiver noise interference and clutter.  Pulse radar system receiver includes mixer, local oscillator, I. F.  Amplifier, detector and video amplifier are included.  Whose functions are as follows - 

1. Mixer and Local Oscillator - The mixer which is present with the local oscillator is R.  F .  The signal is received from the reflective target and in  F .  Reduce signal to frequency  F converts into signals that are called intermediate frequency (IF) signals.  In the mixer stage, career frequency decreases.  Received I.F .  Signal, I.F.  Are fed into the amplifier.
2. Detector - It is a shoty ramp diode that extrudes pulse modulation to the IF amplifier output.  The output of the detector is fed into the upcoming (next stage video amplifier).
3. Video amplifier - The video amplifier amplifies the output of the detector to a level that is helpful to drive the display device (CRT).

• Indicatior or Radar Display - The receiver's output is often fed into the input of the indicator.  Which displays the output on the cathode ray tube (CRT) in such a way that it shows a clear difference between the pulses going and the returning echoes.  C. for this work  R. T.  The K voltage is synchronized with the transmit pulses.