What is frequency modulation in radar?
Frequency-Modulated Continuous-Wave Radar (FMCW Radar) FMCW radar (Frequency-Modulated Continuous Wave radar = FMCW radar) is a special type of radar sensor which radiates continuous transmission power like a simple continuous wave radar (CW-Radar).
What is the principle of FM radar?
The radar principle used is FMCW (Frequency Modulated Continuous Wave). The FMCW-radar transmits a high frequency signal whose frequency increases linearly during the measurement phase (called the frequency sweep). The signal is emitted, reflected from the measuring surface and received with a time delay, t.
What is FSK radar?
What is FSK Radar? FSK stands for Frequency Shift Keying. FSK allows distance measurements (ranging) of moving objects. FSK allows a better resolution than FMCW and uses less bandwidth. FSK uses switching between two discrete carrier frequencies fa and fb, while FMCW uses linear ramps.
Why do we need frequency modulation?
Frequency modulation (FM) Because the frequency of a radio wave is less vulnerable to noise than the amplitude, FM was originally introduced to reduce noise and improve the quality of radio reception. In order to accomplish this, FM radio signals have bandwidth several times that of AM signals.
How is frequency modulation done?
To generate a frequency modulated signal, the frequency of the radio carrier is changed in line with the amplitude of the incoming audio signal. When the audio signal is modulated onto the radio frequency carrier, the new radio frequency signal moves up and down in frequency.
Why pulse compression is used in radar?
Pulse compression allows a radar system to transmit a pulse of relatively long duration and low peak power to attain the range resolution and detection performance of a short-pulse, high-peak power system.
Why FM is preferred over PM?
Answer: FM has higher bandwidth, due to which it is less affected by noise interference. Hence, the signal quality of FM is better than PM.
Why do we use frequency modulation?
What is the difference between pulse radar and CW radar?
Pulsed signals remain powered for short periods of time, working with and without some form of modulation, such as amplitude, frequency, or phase modulation. CW signals remain on constantly and may be modulated to function as radars or in communications systems.
What are the disadvantages of CW radar?
Disadvantages of CW Doppler Radar The maximum range of CW Doppler radar is limited by the power that radar can radiate. The target range cannot be calculated by CW Doppler radar. There is possibility of ambiguous results when number of targets are more.
Why do radars use chirps?
The chirp pulse compression process transforms a long duration frequency-coded pulse into a narrow pulse of greatly increased amplitude. It is a technique used in radar and sonar systems because it is a method whereby a narrow pulse with high peak power can be derived from a long duration pulse with low peak power.
Why is it called pulse compression?
this signal is designed so that after matched filtering, the width of the intercorrelated signals is smaller than the width obtained by the standard sinusoidal pulse, as explained above (hence the name of the technique: pulse compression).
What type of modulation is used in radar?
In simple ranging radars, the carrier will be pulse modulated and in continuous wave systems, such as Doppler radar, modulation may not be required. Most systems use pulse modulation, with or without other supplementary modulating signals.
What is AGC in radar?
In the past, radar AGC was electronically controlled and affected the gain of the entire radar receiver. As radars evolved, AGC became computer-software controlled and affected the gain with greater granularity in specific detection cells. Radar multipath echoes from a target cause ghosts to appear.
What is the maximum Doppler frequency of a radar set?
In this frequency band of these radar sets ( X-Band mostly), the expected maximum Doppler frequency is 666 Hz If the radar signal processing uses a resolution in the kilohertz range per meter, this Doppler frequency is negligible.
What is frequency modulation?
Such a time reference for measuring the distance of stationary objects, but can be generated using of frequency modulation of the transmitted signal. In this method, a signal is transmitted, which increases or decreases in the frequency periodically.