Explanation :

The Block diagram of high power Pulsed RADAR set is shown in fig. Above.

Trigger Source: It Provides pulses for the modulator.

Pulse Modulator: This Modulator provides rectangular voltage pulses which act as the supply voltage to the output tube, thus switching ON & OFF as required.

Output tube: It may be an oscillator tube such as a magnetron oscillator or an amplifier such as klystron, TWT or crossed field amplifier. If an amplifier is used, a source of microwave is also required. The pulse modulated sine wave carrier then travels via duplexer to the antenna where it is radiated into space. A single antenna is generally used for both transmission & reception. Usually parabolic reflectors with center feed arrangements is used.

Duplexer: The duplexer channelize the returned echo signal to the receiver and not to the transmitter. The duplexer consists of gas-discharge tubes, one known as TR tube and other as ATR. The TR tube protects the receiver during transmission and the ATR helps in directing the received echo signals to the receiver.

Receiver: The receiver is usually of superheterodyne type whose function is to detect the desired echo signals in the presence of noise, interference & Clutter. The receiver in Pulsed RADAR consists of the RF amplifier, mixer, local oscillator, IF amplifier, Detector, Video Amplifier & RADAR display.

Low Noise RF amplifier: It is the first stage of the receiver. It is a low noise transmitter amplifier or parametric amplifier or TWT amplifier.

Mixer & Local Oscillator: These converts RF signal output from RF amplifier to comparatively lower frequency levels (IF). Thus, in a mixer stage, the Carrier frequency is reduced.

IF amplifier: This amplifier consists of a cascade of tuned amplifier & Provides the main receiver gain. It should be designed as a matched filter to get maximum peak signal to mean noise power ratio at the output.

Detector: The Detector is often is a schottky-barrier diode which extracts the pulse modulation from the IF amplifier output. The detector output is the amplified by the video amplifier to a level where it can be properly displayed usually on CRT directly or via computer processing and enhancing. Sync pulses are applied by the trigger source to the display devices or the display indicator.