Begginer's Radar Class

[zavis2003]

Mon ami the poster is one man or kid for that matter. I understood your post to be directed toward us all. There are others out there who do understand the field very well. Yes, admittedly I have yet to encounter many people on this forum with that knowledge. But then, most of them now( and truly MOST) are just overzealous fellows fed with the false superiority that our primary education entails and tend to scrape information from wikipedia and present it without knowing anything behind the words and data.
Which is why I carry a bag load of sarcasm to bring them down from their high perch. Call me for my services if you wish.

atleast i am ready for any debate on the radar sys it would be pleasure for me about this discussion of radar to understand something from u and also teach u few words i understood during my engineering life

 

[zavis2003]

http://www.freebookspot.in/Books-Radar%20Handbook,%20Third%20Edition.htm

a good book link is above

 

[SQ8]

atleast i am ready for any debate on the radar sys it would be pleasure for me about this discussion of radar to understand something from u and also teach u few words i understood during my engineering life

Would love to, currently though Ive had enough of radars and a little too busy with embedded systems.

 

[eagle20054]

i simply put a question in front of you though i am known to this

why we used AGC in a monopulse tracking radars ???

i think this may help u....


Gain control is necessary to adjust the receiver sensitivity for the best reception of signals of widely varying amplitudes. A complex form of automatic gain control (agc) or instantaneous automatic gain control (iagc) is used during normal operation. The simplest type of agc adjusts the IF amplifier bias (and gain) according to the average level of the received signal. With agc, gain is controlled by the largest received signals. When several radar signals are being received simultaneously, the weakest signal may be of greatest interest. Iagc is used more frequently because it adjusts receiver gain for each signal.
The agc circuit is essentially a wide-band, dc amplifier. It instantaneously controls the gain of the IF amplifier as the radar return signal changes in amplitude. The effect of iagc is to allow full amplification of weak signals and to decrease the amplification of strong signals. The range of iagc is limited, however, by the number of IF stages in which gain is controlled. When only one IF stage is controlled, the range of iagc is limited to approximately 20 dB. When more than one IF stage is controlled, iagc range can be increased to approximately 40 dB.

 

[gambit]

why we used AGC in a monopulse tracking radars ???

Gain control is necessary to adjust the receiver sensitivity for the best reception of signals of widely varying amplitudes. A complex form of automatic gain control (agc) or instantaneous automatic gain control (iagc) is used during normal operation. The simplest type of agc adjusts the IF amplifier bias (and gain) according to the average level of the received signal. With agc, gain is controlled by the largest received signals. When several radar signals are being received simultaneously, the weakest signal may be of greatest interest. Iagc is used more frequently because it adjusts receiver gain for each signal.
The agc circuit is essentially a wide-band, dc amplifier. It instantaneously controls the gain of the IF amplifier as the radar return signal changes in amplitude. The effect of iagc is to allow full amplification of weak signals and to decrease the amplification of strong signals. The range of iagc is limited, however, by the number of IF stages in which gain is controlled. When only one IF stage is controlled, the range of iagc is limited to approximately 20 dB. When more than one IF stage is controlled, iagc range can be increased to approximately 40 dB.

For the readers, this is basic monopulse radar operation relevant to the highlighted above...



The radar problem of beam dispersion, or widening, with increasing distance make target data processing problematic when the system is making constant adjustment to keep the target inside that little dark area. The system is basically seeing four distinct target returns. Gain control is necessary, especially if there are ECM attempts against one of those four return signals. If the ECM tactic is successful, the system will be forced to constantly recalibrate itself. Gain control can help, not guarantee, to reduce the efficacy of such monopulse jamming tactic. The more sophisticated ECM system will be able to distinguish the four from each other and will jump from signal to signal, complicating the radar's attempt to null out the target. The radar's response would be frequency agility, then the ECM would attempt to track and counter. And so on...

 

[zavis2003]

ok if you are right than tell me that if we apply agc than how we extracts the info from the monopulse radar`s amplitude differences of received signal

 

[SQ8]

Summed Auto correlations??
Spectrum filters doing Auto correlations on signals?