% FILENAME = N17.TXT % Receiver Operation % Release version 3, October 2001 % Q 23 modified 6 Mar 2012 %QUESTION: 1 #17.1 The frequency stability of a receiver is its ability to: stay tuned to the desired signal track the incoming signal as it drifts provide a frequency standard provide a digital readout % ans 1 %QUESTION: 2 #17.2 The sensitivity of a receiver specifies: the bandwidth of the RF preamplifier the stability of the oscillator its ability to receive weak signals its ability to reject strong signals % ans 3 %QUESTION: 3 #17.3 Of two receivers, the one capable of receiving the weakest signal will have: an RF gain control the least internally-generated noise the loudest audio output the greatest tuning range % ans 2 %QUESTION: 4 #17.4 The figure in a receiver's specifications which indicates its sensitivity is the: bandwidth of the IF in kilohertz audio output in watts signal plus noise to noise ratio number of RF amplifiers % ans 3 %QUESTION: 5 #17.5 If two receivers are compared, the more sensitive receiver will produce: more than one signal less signal and more noise more signal and less noise a steady oscillator drift % ans 3 %QUESTION: 6 #17.6 The ability of a receiver to separate signals close in frequency is called its: noise figure sensitivity bandwidth selectivity % ans 4 %QUESTION: 7 #17.7 A receiver with high selectivity has a: wide bandwidth wide tuning range narrow bandwidth narrow tuning range % ans 3 %QUESTION: 8 #17.8 The BFO in a superhet receiver operates on a frequency nearest to that of its: RF amplifier audio amplifier local oscillator IF amplifier % ans 4 %QUESTION: 9 #17.9 To receive Morse code signals, a BFO is employed in a superhet receiver to: produce IF signals beat with the local oscillator signal to produce sidebands produce an audio tone to beat with the IF signal beat with the IF signal to produce an audio tone % ans 4 %QUESTION: 10 #17.10 The following transmission mode is usually demodulated by a product detector: pulse modulation double sideband full carrier modulation frequency modulation single sideband suppressed carrier modulation % ans 4 %QUESTION: 11 #17.11 A superhet receiver for SSB reception has an insertion oscillator to: replace the suppressed carrier for detection phase out the unwanted sideband signal reduce the passband of the IF stages beat with the received carrier to produce the other sideband % ans 1 %QUESTION: 12 #17.12 A stage in a receiver with input and output circuits tuned to the received frequency is the: RF amplifier local oscillator audio frequency amplifier detector % ans 1 %QUESTION: 13 #17.13 An RF amplifier ahead of the mixer stage in a superhet receiver: enables the receiver to tune a greater frequency range means no BFO stage is needed makes it possible to receive SSB signals increases the sensitivity of the receiver % ans 4 %QUESTION: 14 #17.14 A communication receiver may have several IF filters of different bandwidths. The operator selects one to: improve the S-meter readings improve the receiver sensitivity improve the reception of different types of signal increase the noise received % ans 3 %QUESTION: 15 #17.15 The stage in a superhet receiver with a tuneable input and fixed tuned output is the: RF amplifier mixer stage IF amplifier local oscillator % ans 2 %QUESTION: 16 #17.16 The mixer stage of a superhet receiver: produces spurious signals produces an intermediate frequency signal acts as a buffer stage demodulates SSB signals % ans 2 %QUESTION: 17 #17.17 A 7 MHz signal and a 16 MHz oscillator are applied to a mixer stage. The output will contain the input frequencies and: 8 and 9 MHz 7 and 9 MHz 9 and 23 MHz 3.5 and 9 MHz % ans 3 %QUESTION: 18 #17.18 Selectivity in a superhet receiver is achieved primarily in the: RF amplifier Mixer IF amplifier Audio stage % ans 3 %QUESTION: 19 #17.19 The abbreviation AGC means: attenuating gain capacitor automatic gain control anode-grid capacitor amplified grid conductance % ans 2 %QUESTION: 20 #17.20 The AGC circuit in a receiver usually controls the: audio stage mixer stage power supply RF and IF stages % ans 4 %QUESTION: 21 #17.21 The tuning control of a superhet receiver changes the tuned frequency of the: audio amplifier IF amplifier local oscillator post-detector amplifier % ans 3 %QUESTION: 22 #17.22 A superhet receiver, with an IF at 500 kHz, is receiving a 14 MHz signal. The local oscillator frequency is: 14.5 MHz 19 MHz 500 kHz 28 MHz % ans 1 %QUESTION: 23 #17.23 An audio amplifier is necessary in an AM receiver because: signals leaving the detector are weak the carrier frequency must be replaced the signal requires demodulation RF signals are not heard by the human ear % ans 1 %QUESTION: 24 #17.24 The audio output transformer in a receiver is required to: step up the audio gain protect the loudspeaker from high currents improve the audio tone match the output impedance of the audio amplifier to the speaker % ans 4 %QUESTION: 25 #17.25 If the carrier insertion oscillator is counted, then a single conversion superhet receiver has: one oscillator two oscillators three oscillators four oscillators % ans 2 %QUESTION: 26 #17.26 A superhet receiver, with a 500 kHz IF, is receiving a signal at 21.0 MHz. A strong unwanted signal at 22 MHz is interfering. The cause is: insufficient IF selectivity the 22 MHz signal is out-of-band 22 MHz is the image frequency insufficient RF gain % ans 3 %QUESTION: 27 #17.27 A superhet receiver receives an incoming signal of 3540 kHz and the local oscillator produces a signal of 3995 kHz. The IF amplifier is tuned to: 455 kHz 3540 kHz 3995 kHz 7435 kHz % ans 1 %QUESTION: 28 #17.28 A double conversion receiver designed for SSB reception has a carrier insertion oscillator and: one IF stage and one local oscillator two IF stages and one local oscillator two IF stages and two local oscillators two IF stages and three local oscillators % ans 3 %QUESTION: 29 #17.29 An advantage of a double conversion receiver is that it: does not drift off frequency produces a louder audio signal has improved image rejection characteristics is a more sensitive receiver % ans 3 %QUESTION: 30 #17.30 A receiver squelch circuit: automatically keeps the audio output at maximum level silences the receiver speaker during periods of no received signal provides a noisy operating environment is not suitable for pocket-size receivers % ans 2