Subelement C: Receiving Systems – 10 Key Topics – 10 Exam Questions – 4 Drawings— Topic 25: Sea Clutter - STC
Question 8-25C6
Element 8 (RADAR)The sensitivity time control (STC) circuit:
Explanation
The Sensitivity Time Control (STC) circuit, often used in radar systems, manages the receiver's gain immediately after a pulse transmission. Its primary function is to prevent the receiver from being overloaded by very strong echoes from nearby objects. By temporarily *decreasing* the receiver's sensitivity (gain) right after the transmit pulse, STC effectively attenuates strong returns from close-range targets. The sensitivity then gradually increases over time, allowing weaker echoes from more distant objects to be detected without being masked by the strong close-in signals. Therefore, it decreases sensitivity for close objects.
Options B and C are incorrect because STC reduces, not increases, sensitivity for close objects, and while it *enables* detection of distant objects, its fundamental control action is the initial decrease in sensitivity. Option D is incorrect because STC controls the *receiver's* sensitivity, not the transmitter's.
Related Questions
8-25C4 Sea clutter on the RADAR scope cannot be effectively reduced using front panel controls. What circuit would you suspect is faulty?8-25C5 What circuit controls the suppression of sea clutter?8-26C1 Prior to making “power-on” measurements on a switching power supply, you should be familiar with the supply because of the following:8-26C2 A constant frequency switching power supply regulator with an input voltage of 165 volts DC, and a switching frequency of 20 kHz, has an “ON” time of 27 microseconds when supplying 1 ampere to its load. What is the output voltage across the load?8-26C3 The circuit shown in Fig. 8C10 is the output of a switching power supply. Measuring from the junction of CR6, CR7 and L1 to ground with an oscilloscope, what waveform would you expect to see?