Block Diagram of Pulsed Radar System – Explanation | New Topic

In this note, we are going to learn about the block diagram of pulsed radar system. We have explained each block of the diagram. Welcome to Poly Notes Hub, a leading destination for engineering notes for diploma and degree engineering students.

Author Name: Arun Paul.

What is Pulsed Radar System?

A Pulsed Radar System is a form of radar that sends high-power radio frequency (RF) pulses toward a target and then listens for echoes bounced back from objects in its path. It works in a time-sharing mode, transmitting briefly before receiving during the time gap between pulses.

Applications of Pulsed Radar System

• Used in Air traffic surveillance
• Used in Ship and aircraft navigation
• Used in Military tracking and missile guidance
• Used in Weather forecasting (storm tracking)
• Used in Speed detection (police radar guns)

Block Diagram of Pulsed Radar System with Explanation

Here is the pulsed radar system block diagram, along with an explanation of each block.

• Trigger Source: The trigger source generates a timing signal, which starts the full radar operation. This pulse synchronizes the transmitter and reception parts. It determines pulse repetition frequency and radar pulse timing.
• Modulator: The modulator shapes the pulse and feeds it into the microwave oscillator. It controls pulse width and timing, allowing for short, high-energy bursts. This enables the effective transmission of signals across great distances with precision.
• Microwave Oscillator: The microwave oscillator (also known as a magnetron or klystron) generates the high-frequency radio waves required for radar transmission. It converts the modulator’s electrical pulses to RF signals before sending them to the duplexer for transmission.
• Duplexer: The duplexer is a vital switch that toggles radar functioning between broadcast and receive modes. It enables a single antenna to transmit and receive signals while protecting the receiver from high-power pulses.
• Antenna: The antenna sends the sent pulse into space and receives echo signals reflected by objects. It serves a dual purpose by delivering and receiving electromagnetic waves with great directional precision and negligible losses.
• Mixer: The mixer adds the received echo signal to the signal from the local oscillator. This generates an intermediate frequency (IF) signal. The IF signal is easier to amplify and process than the original high-frequency wave.
• Local Oscillator: The local oscillator generates a stable frequency used for converting the received echo signal to an intermediate frequency. It helps improve radar resolution, enhances signal clarity, and aids in Doppler shift and target velocity measurement.
• IF Amplifier: The intermediate frequency amplifier boosts the power of the IF signal without distorting it. It amplifies weak received signals, increasing the signal-to-noise ratio and allowing for greater target recognition and resolution at extended distances.
• Detector: The detector extracts the modulation from the amplified IF signal, converting it to a baseband video signal. This is the stage where useful information like target range and strength is separated from the carrier wave.
• Video Amplifier: The video amplifier amplifies the baseband signal retrieved by the detector. It improves the visibility of the target echo by amplifying tiny signals before sending them to the display unit for observation and analysis.
• Indicator: The indicator is usually a visual display (like CRT, LCD, or digital monitor) that presents information about the detected target—distance, speed, and direction. It helps operators analyze data and make real-time decisions based on radar output.