% FILENAME = N25.TXT % Receiver Block Diagrams % Release version 3, October 2001 % Q 15 and 19 changed 6 Mar 2012 %Question: 1 #16.1 In the block diagram of the receiver shown, the "RF amplifier":

decreases random fluctuation noise is a restoring filter amplifier increases the incoming signal level changes the signal frequency % ans 3 %Question: 2 #16.2 In the block diagram of the receiver shown, the "mixer":

combines signals at two different frequencies to produce one at an intermediate frequency combines sidebands to produce a stronger signal discriminates against SSB and AM signals inserts a carrier wave to produce a true FM signal % ans 1 %Question: 3 #16.3 In the block diagram of the receiver shown, the output frequency of the "oscillator" is:

the same as that of the incoming received signal the same as that of the IF frequency different from both the incoming signal and IF frequencies at a low audio frequency % ans 3 %Question: 4 #16.4 In the block diagram of the receiver shown, the "filter" rejects:

AM and RTTY signals unwanted mixer outputs noise bursts broadcast band signals % ans 2 %Question: 5 #16.5 In the block diagram of the receiver shown, the "IF amplifier" is an:

isolation frequency amplifier intelligence frequency amplifier indeterminate frequency amplifier intermediate frequency amplifier % ans 4 %Question: 6 #16.6 In the block diagram of the receiver shown, the "product detector":

produces an 800 Hz beat note separates CW and SSB signals rejects AM signals translates signals to audio frequencies % ans 4 %Question: 7 #16.7 In the block diagram of the receiver shown, the "AF amplifier":

rejects AM and RTTY signals amplifies audio frequency signals has a very narrow passband restores ambiance to the audio % ans 2 %Question: 8 #16.8 In the block diagram of the receiver shown, the "BFO" stands for:

bad frequency obscurer basic frequency oscillator beat frequency oscillator band filter oscillator % ans 3 %Question: 9 #16.9 In the block diagram of the receiver shown, most of the receiver gain is in the:

RF amplifier IF amplifier AF amplifier mixer % ans 2 %Question: 10 #16.10 In the block diagram of the receiver shown, the "RF amplifier":

decreases random fluctuation noise masks strong noise should produce little internal noise changes the signal frequency % ans 3 %Question: 11 #16.11 In the block diagram of the receiver shown, the "mixer":

changes the signal frequency rejects SSB and CW signals protects against receiver overload limits the noise on the signal % ans 1 %Question: 12 #16.12 In the receiver shown, when receiving a signal, the output frequency of the "oscillator" is:

the same as that of the signal the same as that of the IF amplifier of constant amplitude and frequency passed through the following filter % ans 3 %Question: 13 #16.13 In the block diagram of the receiver shown, the "limiter":

limits the signal to a constant amplitude rejects SSB and CW signals limits the frequency shift of the signal limits the phase shift of the signal % ans 1 %Question: 14 #16.14 In the block diagram of the receiver shown, the "frequency demodulator" could be implemented with a:

product detector phase-locked loop full-wave rectifier low-pass filter % ans 2 %Question: 15 #16.15 In the block diagram of the receiver shown, the "AF amplifier":

amplifies stereo signals amplifies speech frequencies is an all frequency amplifier must be fitted with a tone control % ans 2 %Question: 16 #16.16 In this receiver, an audio frequency gain control would be associated with the block labelled:

AF amplifier frequency demodulator speaker, phones IF amplifier % ans 1 %Question: 17 #16.17 In the block diagram of the receiver shown, the selectivity would be set by the:

AF amplifier mixer limiter filter % ans 4 %Question: 18 #16.18 In the FM communications receiver shown in the block diagram, the "filter" bandwidth is typically:

3 kHz 10 kHz 64 kHz 128 kHz % ans 2 %Question: 19 #16.19 In the block diagram of the receiver shown, an automatic gain control (AGC) circuit would be associated with the:

Speaker IF amplifier RF filter Oscillator % ans 2 %Question: 20 #16.20 In the block diagram of the receiver shown, the waveform produced by the "oscillator" would ideally be a:

square wave pulsed wave sinewave hybrid frequency wave % ans 3