9 2-9.   Which of the following characteristics is NOT a requirement of a basic radar system timing circuit? 1.     It must be free-funning 2.     Frequency must be variable 3.     It must develop random frequencies 4.     It should provide a stable frequency 2-10.   Which of the following circuits converts square waves to positive and negative triggers? 1.     A negative limiter 2.     A positive limiter 3.     A long-time-constant RC differentiator 4.     A short-time-constant RC differentiator 2-11.   Which of the following circuits is used to remove either the negative or positive triggers from the output of a sine-wave oscillator? 1.     A clipper 2.     A limiter 3.     An LC network 4.     A differentiator 2-12.   When the master oscillator in a multivibrator timer is asymmetrical, the output of the master oscillator is in the form of 1.     rectangular waves 2.     negative pulses 3.     square waves 4.     sine waves 2-13.   The positive and negative output pulses of the astable multivibrator are sent to the indicator for which of the following purposes? 1.     To intensify the crt beam 2.     To gate the range-marker generator 3.     Both 1 and 2 above 4.     To gate the transmitter output 2-14.   Which of the following oscillators generates sharp trigger pulses without additional circuitry? 1.     Sine-wave oscillator 2.     Wien-bridge oscillator 3.     One-shot multivibrator 4.     Single-swing blocking oscillator 2-15.   A radar transmitter is triggered directly by high voltage pulses from what unit? 1.     The timer 2.     The antenna 3.     The indicator 4.     The modulator 2-16.   The peak power of a transmitted rf pulse depends on which of the following factors? 1.    Width of the modulator pulse 2.    Amplitude of the modulator pulse 3.    Prf of trigger pulses from the timer 4.    Delay time between trigger and modulator pulse outputs 2-17.   The transmitter range timing circuit must be triggered at the instant the transmitted pulse leaves the transmitter.  For which of the following reasons is this timing so important? 1.     To ensure accurate range 2.     The ensure long range targets are detected 3.     To ensure that the target is "painted" on the crt by each transmitted pulse 4.     To keep the magnetron oscillating at a fixed frequency 2-18.   For proper operation of the magnetron, the modulator pulse must have which of the following characteristics? 1.     A flat top 2.     A steep leading edge 3.     A steep trailing edge 4.     All of the above