rf trans vol 1 unit 1

1.

1 point

Which fiber-optic connector uses quick-release, keyed bayonet couplings that are preferred in situations where severe vibrations are not expected?

Straight tip (ST).

Field (FC).

Sub-miniature, type A (SMA).

Biconic.

2.

1 point

In phase modulation, what part of the carrier signal is varied?

Amplitude.

Height.

Phase.

Frequency.

3.

1 point

What photo detector converts one photon to one electron?

Integrated photodiode/preamplifier.

Positive intrinsic negative diode.

Avalanche photodiode.

Light emitting diode.

4.

1 point

In phase modulation, the carrier’s

phase is shifted at the rate of the modulating signal.

amplitude is shifted at the rate of the modulating signal.

amplitude is shifted with the phase of the modulating signal.

phase shifted with the phase of the modulating signal.

5.

1 point

What are the three general categories used to produce modulation in radio frequency (RF) transmission today?

Binary amplitude shift keying, frequency shift keying, and phase shift keying.

Amplitude, frequency, and phase.

Pulse amplitude, pulse width, and pulse position.

Analog, digital and shift keying.

6.

1 point

In frequency modulation, a significant sideband contains at least what percentage of the total transmitted power?

1

10

3

0.1

7.

1 point

In asynchronous transmissions, what bit is used by the receiving device to verify that the transmission was received correctly?

Start.

Control.

Parity.

Stop.

8.

1 point

What part of the pulse code modulation process converts a continuous time signal into a discrete time signal?

Sampling.

Band limiting.

Oscillating.

Rectifying.

9.

1 point

A short section of single fiber cable that has a connector at each end is called a

jumper.

pigtail.

breakout cables.

patch cord.

10.

1 point

What is the formula to find the modulating index?

Deviation divided by frequency of modulation.

Sideband times carrier frequency.

Deviation times frequency of modulation.

Sideband divide by carrier frequency.

11.

1 point

When using forward error control as a method of error correction, where does error correction take place?

In the primary buffers.

Receiving end.

In the oscillator.

Transmitting end.

12.

1 point

What is it called when a narrow frequency band between adjacent stations prevent frequency modulated sidebands from overlapping?

Buffer zone

Prevention field.

Space.

Guard band.

13.

1 point

Which statement concerning bandwidth is true?

Overmodulating increases bandwidth because the output’s increased amplitude.

Undermodulating increases bandwidth because the output’s decreased amplitude.

Overmodulating increases bandwidth because the distortion produces harmonics.

Undermodulating increases bandwidth because the distortion produces harmonics.

14.

1 point

What type of light is emitted from a laser?

Ordinary.

Coherent.

Incoherent.

Invisible.

15.

1 point

When the modulating signal and carrier signal are combined within a modulator, the output signal contains

carrier and modulating signal.

carrier, upper sideband, and lower sideband.

modulating signal, upper sideband, and lower sideband.

upper sideband and modulating signal.

16.

1 point

The bandwidth of an amplitude modulated signal is

determined by the modulation index.

two times the modulating signal.

defined in terms of maximum amount of modulation.

the same as the modulating signal.

17.

1 point

Which repeater amplifies optical signal without converting to and from the electrical domain?

Repeaters.

Receiver.

Optical amplifiers.

Regenerators.

18.

1 point

What are the two main types of photodetectors?

Tunnel and zener diodes.

Positive intrinsic negative and avalanche photodiode.

Light emitting diode and semiconductor laser.

Light-emitting diode and avalanche photodiode.

19.

1 point

When using vertical redundancy check, what significance does the amount of ones have in a data bit pattern?

Determines transmission rate.

Determines parity.

Determines whether transmission is in ASCII format.

Determines whether transmission is synchronous or asynchronous.

20.

1 point

What error detection method is used for checking a data block greater than 512 and is about 99 percent effective in most applications?

Checksum.

Vertical redundancy check.

Cyclic redundancy check

Longitudinal redundancy check.

21.

1 point

Light sources that are applicable to fiber optic waveguide are light-emitting diodes and

semiconductor laser diodes.

integrated photodiode/preamplifiers.

photo transistors.

hybrid photodiodes

22.

1 point

The output of the oscillator in a frequency modulation (FM) modulator increases in frequency with each

negative half cycle of the carrier.

positive half cycle of the modulating signal.

negative half cycle of the modulating signal.

positive half cycle of the carrier.

23.

1 point

What is one reason for modulation that involves modulating low frequency signals for transmission over long distances?

ease of radation

channel allocation

companding

spectrum conservation

24.

1 point

Use the formula on page 1–3. If an oscilloscope displays a modulation envelope having an Emax of 200 volts and an Emin of 20 volts, what is the modulation percentage?

88

81.8

85.5

122

25.

1 point

If an error should occur, what transmission is lost in an synchronous transmission?

One character.

Block of data.

A parity bit.

A stop bit.

26.

1 point

A 5 kHz modulating signal has enough peak voltage to cause a deviation of 15 kHz. What is the modulation index?

0.5

5

0.3

3

27.

1 point

What is the first step in the pulse code modulation process?

The quantizer limits the amplitude of the pulses.

Discrete amplitudes are assigned to the sampling pulses.

The analog signal is band limited.

A binary code number is assigned to the sample.

28.

1 point

If a carrier frequency of 1 MHz and a modulating tone of 10 kHz goes to the modulator, the output signal include

1.11 MHz, 1 MHz, 0.99 MHz.

1.01 MHz, 1 MHz, and 0.99 MHz.

1.1 MHz, 1 MHz, and 0.9 MHz.

1.111 MHz, 1 MHz, 0.999 MHz.