Question 1

Noise is usually clipped by:

Accepted Answer

A)  limiter circuits 
B)  phase detectors 
C)  ARC circuits 
D)  amplifiers. 
A)  limiter circuits 
B)  phase detectors 
C)  ARC circuits 
D)  amplifiers.

Question 2

If the S/N of the input signal is 4 and the intelligence signal is 10 kHz, determine the deviation

Accepted Answer

A)  200 kHz 
B)  100 kHz 
C)  145 kHz 
D)  160 kHz 
A)  200 kHz 
B)  100 kHz 
C)  145 kHz 
D)  160 kHz

Question 3

De-emphasis is:

Accepted Answer

A)  increasing the relative strength of high frequency components before being fed into the modulator of an FM transmitter. 
B)  increasing the relative strength of low-frequency components before being fed into the modulator of an FM transmitter. 
C)  decreasing the relative strength of low-frequency components of the output signal of an FM detector of an FM receiver. 
D)  decreasing the relative strength of high-frequency components of the output signal of an FM detector in an FM receiver. 
A)  increasing the relative strength of high frequency components before being fed into the modulator of an FM transmitter. 
B)  increasing the relative strength of low-frequency components before being fed into the modulator of an FM transmitter. 
C)  decreasing the relative strength of low-frequency components of the output signal of an FM detector of an FM receiver. 
D)  decreasing the relative strength of high-frequency components of the output signal of an FM detector in an FM receiver.

Question 4

In this modulator, FM is created by having the intelligence signal cause a change in the transconductance of a JFET, which causes a change in the JFET amplifier's input capacitance, which shifts the resonant frequency of a tank circuit:

Accepted Answer

A)  PLL modulator 
B)  VCO modulator 
C)  reactance modulator 
D)  varactor diode modulator 
A)  PLL modulator 
B)  VCO modulator 
C)  reactance modulator 
D)  varactor diode modulator

Question 5

Pre-emphasis is:

Accepted Answer

A)  increasing the relative strength of low-frequency components before being fed into the modulator of an FM transmitter. 
B)  decreasing the relative strength of high-frequency components at the output signal of an FM detector in an FM receiver 
C)  decreasing the relative strength of low-frequency components of the output signal of an FM detector in an FM receiver. 
D)  increasing the relative strength of high-frequency components before being fed into the modulator of an FM transmitter. 
A)  increasing the relative strength of low-frequency components before being fed into the modulator of an FM transmitter. 
B)  decreasing the relative strength of high-frequency components at the output signal of an FM detector in an FM receiver 
C)  decreasing the relative strength of low-frequency components of the output signal of an FM detector in an FM receiver. 
D)  increasing the relative strength of high-frequency components before being fed into the modulator of an FM transmitter.

Question 6

The noise characteristics of an FM communication system are mainly due to:

Accepted Answer

A)  its limiter and detector stages 
B)  its narrow bandwidth characteristics 
C)  its low level of modulation index 
D)  its modulator stage 
A)  its limiter and detector stages 
B)  its narrow bandwidth characteristics 
C)  its low level of modulation index 
D)  its modulator stage

Question 7

Viewing an FM signal on a spectrum analyzer, if the carrier frequency component is zero and there are four or five sidebands on either side of the carrier frequency, the index of modulation is:

Accepted Answer

A)  0 
B)  5.5 
C)  2.2 
D)  8.65 
A)  0 
B)  5.5 
C)  2.2 
D)  8.65

Question 8

To solve for the frequency components of an FM signal, what high-level mathematical tool is used?

Accepted Answer

A)  Fourier transforms 
B)  LaPlace transforms 
C)  Bessel functions 
D)  Calculus 
A)  Fourier transforms 
B)  LaPlace transforms 
C)  Bessel functions 
D)  Calculus

Question 9

In an FM stereo transmitter, the L+R audio signal applied to the FM modulator stage

Accepted Answer

A)  extends only from 23 kHz to 38 kHz 
B)  extends from 23 kHz to 53 kHz 
C)  extends from 0 to 15 kHz 
D)  extends only from 38 kHz to 53 kHz 
A)  extends only from 23 kHz to 38 kHz 
B)  extends from 23 kHz to 53 kHz 
C)  extends from 0 to 15 kHz 
D)  extends only from 38 kHz to 53 kHz

Question 10

An FM signal has a center frequency of 154.5 MHz but is swinging between 154.45 MHz and 154.55 MHz at a frequency of 500 times per second. Its input carrier frequency is:

Accepted Answer

A)  154.5 MHz 
B)  100 kHz 
C)  500 Hz 
D)  50 kHz. 
A)  154.5 MHz 
B)  100 kHz 
C)  500 Hz 
D)  50 kHz.

Question 11

An FM signal has a center frequency of 154.5 MHz but is swinging between 154.45 MHz and 154.55 MHz at a rate of 500 times per second. Its index of modulation is:

Accepted Answer

A)  100,000. 
B)  500 
C)  50,000 
D)  100. 
A)  100,000. 
B)  500 
C)  50,000 
D)  100.

Question 12

An FM signal has a center frequency of 154.5 MHz, but is swinging between 154.45 MHz and 154.55 MHz at a rate of 500 times per second. Its input intelligence frequency is:

Accepted Answer

A)  100 kHz 
B)  500 Hz. 
C)  154.5 MHz 
D)  50 kHz. 
A)  100 kHz 
B)  500 Hz. 
C)  154.5 MHz 
D)  50 kHz.

Noise is usually clipped by:

If the S/N of the input signal is 4 and the intelligence signal is 10 kHz, determine the deviation

De-emphasis is:

In this modulator, FM is created by having the intelligence signal cause a change in the transconductance of a JFET, which causes a change in the JFET amplifier's input capacitance, which shifts the resonant frequency of a tank circuit:

Pre-emphasis is:

The noise characteristics of an FM communication system are mainly due to:

Viewing an FM signal on a spectrum analyzer, if the carrier frequency component is zero and there are four or five sidebands on either side of the carrier frequency, the index of modulation is:

To solve for the frequency components of an FM signal, what high-level mathematical tool is used?

In an FM stereo transmitter, the L+R audio signal applied to the FM modulator stage

An FM signal has a center frequency of 154.5 MHz but is swinging between 154.45 MHz and 154.55 MHz at a frequency of 500 times per second. Its input carrier frequency is:

An FM signal has a center frequency of 154.5 MHz but is swinging between 154.45 MHz and 154.55 MHz at a rate of 500 times per second. Its index of modulation is:

An FM signal has a center frequency of 154.5 MHz, but is swinging between 154.45 MHz and 154.55 MHz at a rate of 500 times per second. Its input intelligence frequency is:

Introductory Topics

Amplitude Modulation: Transmission

Amplitude Modulation: Reception

Single-Sideband Communications

Frequency Modulation: Reception

Communications Techniques

Digital Communications: Coding Techniques

Wired Digital Communications

Wireless Digital Communications

Network Communications

Transmission Lines

Wave Propagation

Antennas

Waveguides and Radar

Microwaves and Lasers

Television

Fiber Optics

Filters

Exam 5: Frequency Modulation: Transmission

Noise is usually clipped by:

If the S/N of the input signal is 4 and the intelligence signal is 10 kHz, determine the deviation

De-emphasis is:

In this modulator, FM is created by having the intelligence signal cause a change in the transconductance of a JFET, which causes a change in the JFET amplifier's input capacitance, which shifts the resonant frequency of a tank circuit:

Pre-emphasis is:

The noise characteristics of an FM communication system are mainly due to:

Viewing an FM signal on a spectrum analyzer, if the carrier frequency component is zero and there are four or five sidebands on either side of the carrier frequency, the index of modulation is:

To solve for the frequency components of an FM signal, what high-level mathematical tool is used?

In an FM stereo transmitter, the L+R audio signal applied to the FM modulator stage

An FM signal has a center frequency of 154.5 MHz but is swinging between 154.45 MHz and 154.55 MHz at a frequency of 500 times per second. Its input carrier frequency is:

An FM signal has a center frequency of 154.5 MHz but is swinging between 154.45 MHz and 154.55 MHz at a rate of 500 times per second. Its index of modulation is:

An FM signal has a center frequency of 154.5 MHz, but is swinging between 154.45 MHz and 154.55 MHz at a rate of 500 times per second. Its input intelligence frequency is:

Introductory Topics

Amplitude Modulation: Transmission

Amplitude Modulation: Reception

Single-Sideband Communications

Frequency Modulation: Reception

Communications Techniques

Digital Communications: Coding Techniques

Wired Digital Communications

Wireless Digital Communications

Network Communications

Transmission Lines

Wave Propagation

Antennas

Waveguides and Radar

Microwaves and Lasers

Television

Fiber Optics

Filters