6 1-48.   The process of heterodyning takes place in which of the following receiver circuits? 1.   Mixer 2.   Comparator 3.   Oscillator 4.   Second IF amplifier 1-49.   Of the following frequencies, which one is a typical value of IF for AM communications receivers? 1.   455 kilohertz 2.   554 kilohertz 3.   455 megahertz 4.   554 megahertz 1-50.   Two or more circuits within a receiver are varied by a single control through the use of which of the following processes? 1.   Ganged tuning 2.   Frequency synthesis 3.   Automatic gain control 4.   Automatic frequency control 1-51.   There are electrical differences between AM and fm receivers.  An fm receiver contains which of the following circuits? 1.   Comparator 2.   Discriminator 3.   Limiter 4.   Both 2 and 3 above 1-52.   An fm signal has which of the following characteristics when compared to an AM signal? 1.   More noise 2.   Less static 3.   A higher power output 4.   A lower operating frequency 1-53.   Ssb transmissions have which of the following characteristics when compared   to AM transmissions? 1.   Wide bandpass frequencies 2.   Concentrated power 3.   Less modulation 4.   High fidelity 1-54.   Single sideband receivers use a special oscillator.  The output of that oscillator is fed directly to the detector circuit.  What type of oscillator is used? 1.   Local 2.   High frequency 3.   Variable frequency 4.   Carrier reinsertion 1-55.   A transmitter has a suppressed carrier frequency of 4 megahertz and is radiating only an upper sideband signal.  When the intelligence is a 1-kilohertz tone, which of the following sideband frequencies will be transmitted? 1.   3,999 kilohertz 2.   4,000 kilohertz 3.   4,001 kilohertz 4.   Both 2 and 3 above 1-56.   Manual gain lets you adjust a receiver for maximum sensitivity and amplify weak input signals.  Which of the following internal sections of the receiver are varied by this control? 1.   Oscillator 2.   Audio frequency 3.   Radio frequency 4.   Intermediate frequency 1-57.   Manual volume control of a receiver internally varies the input to which of the following circuits? 1.   Detector 2.   Audio amplifier 3.   Frequency converter 4.   Radio frequency amplifier