4.
A combination of a resistor and capacitor is commonly used to reduce
electrical noise.
This combination of components will usually be found
connected across
a. movable parts of shielding.
b. radio receiver to ground leads.
c. telegraph relay keying contacts.
d. commutators of motors and generators.
5.
Peak limiters improve S/N in terminal equipment that demodulates an
FM-type signal. However, peak limiters cannot be used on AM signals because
limiters
a. distort the quality of the signals.
b. limit the bandpass and prevent passage of all signal elements.
c.
balance out the carrier, leaving only the sidebands to heterodyne
and create distortion.
d. remove selected noise components and in the process remove desired
signal components.
6.
When two adjacent AM signals are received, the carriers sometimes
interact and cause heterodyning. This condition usually causes
a. an audio beat frequency within the bandpass of the radio receiver
output signal.
b. the receiver to pick up the stronger of the two signals, to the
detriment of the weaker.
c. an increase in the background noise due to the reduction of AGC
voltage.
d. the peak limiters to react, thus improving the S/N by clipping the
heterodyning noise.
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