Electronics 3rd quarter

• Radar (Radio Detection and Ranging) is a device or system consisting usually of a synchronized radio transmitter and receiver that emits radio waves and processes their reflections for display and is used especially for detecting and locating objects or surface features.
• In modern radar systems, we transmit the waves in "beams" using an antenna which focuses the radar energy onto a parabolic reflector.
• The signal processor is that part of the system which separates targets from clutter on the basis of Doppler content and amplitude characteristics.
• In modern radar sets, the conversion of radar signals to digital form is typically accomplished after IF amplification and phase sensitive detection.
• Radar is the use of radio waves to detect and monitor various objects by emitting a concentrated radio wave and listening for any echo.
• If there is an object in the path of the radio wave, it will reflect some of the electromagnetic energy, and the radio wave will bounce back to the radar device.
• Radar detectors measure how much the speed and frequency of the returned radio waves have changed.
• More cars come with radar-emitting devices, and many of those devices operate on police frequency bands.
• Laser radars (or ladar - laser detection and range) are an extension of conventional microwave radar to shorter wavelengths covering from the ultraviolet to visible and infrared.
• Today, radar is used to detect and track aircraft, spacecraft, and ships at sea as well as insects and birds in the atmosphere; measure the speed of automobiles; map the surface of the earth from space; and measure properties of the atmosphere and oceans.
• Detection range can be as low as 100 feet or less to over a mile.
• A radar system consists of a transmitter producing electromagnetic waves in the radio or microwaves domain, a transmitting antenna, a receiving antenna (often the same antenna is used for transmitting and receiving) and a receiver and processor to determine properties of the object(s).
• Radar works in the rain, but the range of the radar beam is partly diffused by rain or fog, so the object in the beam must be closer so that more of the beam can contact the surface of the moving object to reflect back to the radar unit.
• Laser (Light Amplification Through Stimulated Emission of Radiation) is a device that transmits an audio signal from the “boom box” at left to the auxiliary input of the receiver at right, and you hear it through the speaker.
• The receiver amplifies this signal and plays it through the speaker.
• As communication travels, the waves spread out.
• The infrared light used for laser communications differs from radio waves because the infrared light packs the data into significantly tighter waves, meaning ground stations can receive more data at once.
• From the earliest days of laser development, researchers realized that light could outperform radio in terms of information speed and density.
• Light wavelengths are packed much more tightly than sound waves, and they transmit more information per second, and with a stronger signal.