Modern Electronic Communication by Gary Miller Chapter 6 with Answers

Chapter 6: Frequency Modulation Reception

1	A difference between AM and FM receiver block diagrams is that the FM version includes a
	a. Limiter
	b. Discriminator
	c. Deemphasis network
	d. All the above
2	An FM receiver rarely works satisfactorily without an RF amplifier because
	a. FM receivers typically work with smaller input signal levels due to thei noise     characteristics
	b. FM receivers have a narrower bandwidth.
	c. FM receivers do not have very much gain in their IF amplifier stages.
	d. FM receivers need RF amplifier stages to be able to decode stereo signals.
3	A certain FM receiver provides a voltage gain of 113 dB prior to its limiter. The limiter's quieting voltage is 400 mV. Its sensitivity is approximately
	a.
	b.
	c.
	d.
4	The use of dual-gate MOSFETs in RF amplifier stages
	a. Offers increased dynamic range over those of JFETs
	b. Produces higher-frequency responses than do JFETs
	c. Produces higher values of voltage gain than do JFETs
	d. Is not compatible with AGC
5	The Foster-Seely detector design is superior to the ratio detector in that it
	a. Does not respond to any undesired amplitude variations
	b. Also provides an output AGC signal
	c. Offers superior linear response to wideband FM deviations
	d. Does not need a limiter stage
6	Local oscillator reradiation refers to radiation through the
	a. Receiver's wiring
	b. IF transformer
	c. Antenna
	d. All the above
7	Which is not one of the three stages in which a PLL can be operated?
	a. Free-running
	b. Capture
	c. Locked/tracking
	d. Searching
8	A PLL is set up so that its VCO free-runs at 8.9 Mhz. The VCO does not change frequency unless its input is within 75 kHz of 8.9 Mhz. After it does lock, the input frequency can be adjusted within 120 kHz of 8.9 Mhz without having the PLL start to free-run again. The capture range of the PLL is
	a. 75 kHz
	b. 120 kHz
	c. 150 kHz
	d. 240 kHz
9	Slope detection is seldom used due to
	a. Nonlinearity
	b. Attenuation
	c. Complexity
	d. All the above
10	In an FM stereo receiver, what is the purpose of the 23–53-kHz filter?
	a. To filter out the SCA signal at the output of the discriminator
	b. To filter out the L – R signal at the output of the discriminator
	c. To filter out the L + R signal at the output of the discriminator
	d. To produce separate L and R signals from the L + R and L – signals
11	A dual audio amplifier is rated to provide 65 dB of channel separation. If the right channel has 4 W of output power, how much of this power could be due to the left channel intelligence?
	a. 4 W
	b. 79 nW
	c. 1.26 W
	d. 2.25 mW
12	The hold-in range for a PLL concerns the
	a. Range of frequencies in which it will remain locked
	b. Allowable range of dc voltage
	c. Allowable range of ac input voltage
	d. Satisfactory range of operating temperatures
13	The input signal into a PLL is at the
	a. VCO
	b. Low-pass filter
	c. Comparator
	d. Phase detector
14	The square-law relationship of the FETs input versus output
	a. Allows for greater sensitivity in an FM receiver
	b. Provides improved noise performance
	c. Reduces shot noise
	d. Minimizes cross-modulation
15	When troubleshooting a stereo demodulator, the input signal should be abouto
	a.
	b.
	c. 1 mV rms d. 100 mV rms

Answers:

D

A

C

A

C

C

D

C

A

B

C

A

D

D

D