Vol1 URE1 CDC 3D153

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

1.01 MHz, 1 MHz, and 0.99 MHz.

1.1 MHz, 1 MHz, and 0.9 MHz.

1.11 MHz, 1 MHz, 0.99 MHz.

1.111 MHz, 1 MHz, 0.999 MHz

2. (001) What reason for modulation involves modulating low frequency signals for transmission over long distances?

Spectrum conservation

Channel Allocation

Ease of Radiation

Companding

3. (002) The amount of effect or change that the intelligence has on the carrier in an amplitude modulated signal is expressed as the?

Percent of modulation

Modulation index.

Bandwidth

Deviation

4. (001) 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.

Pulse amplitude, pulse width, and pulse position.

Amplitude, frequency, and phase.

Analog, digital and shift keying.

5. (008) What type of light is emitted from a laser?

Incoherent

Coherent

Ordinary

Invisible

6. (002) The bandwidth of an amplitude modulated signal is?

Two times the modulating signal

The same as the modulating signal

Determined by the modulation index.

Defined in terms of maximum amount of modulation

7. (002) If the modulating audio signal is 10 kHz wide, what is the bandwidth of the transmitted amplitude modulated signal?

5kHz

10kHz

15kHz

20kHz

8. (003) What is the formula to find the modulating index?

Deviation divided by frequency of modulation

Deviation times frequency of modulation

Sideband divide by carrier frequency

Sideband times carrier frequency

9. (005) What part of the pulse code modulation (PCM) process converts a continuous time signal into a discrete time signal?

Sampling

Rectifying

Oscillating

Band limiting

10. (005) A type of pulse modulation (PM) that changes the amplitude of the pulse train to vary according to the amplitude of the input signal is called?

Pulse width modulation (PWM).

Pulse position modulation

Pulse duration modulation

Pulse amplitude modulation

11. (010) What is used to extend the distance of a fiber optic communication systems link?

Receiver

Transmitter

Repeater

Patch cords

12. (002) When the modulating signal and carrier signal are combined within a modulator, the output signal contains a/an

Modulating signal, upper sideband, lower sideband

Carrier, upper sideband, and lower sideband

Upper sideband and modulating signal

Carrier and modulating signal.

13. (002) Which statement concerning bandwidth is true?

Overmodulating increases bandwidth due to the production of harmonics

Undermodulating increases bandwidth due to the production of harmonics

Overmodulating increases bandwidth due to the output’s increased amplitude

Undermodulating increases bandwidth due to the output’s decreased amplitude

14. (008) Laser diode power coupling is measured in which range?

Megawatt

Microwatt

Milliwatt

Kilowatt

15. (003) In frequency modulation (FM), what is considered a significant sideband?

Sidebands containing at least 1 percent of the total transmitted power

Sidebands containing at least 3 percent of the total transmitted power

Sidebands containing at least 10 percent of the total transmitted power

Sidebands containing at least 0.1 percent of the total transmitted power

16. (007) When using forward error control as a method of error correction, where does error correction take place?

Receiving end.

In the oscillator

Transmitting end.

In the primary buffers

17. (009) What photo detector converts one photon to one electron?

Light emitting diode (LED)

Avalanche photodiode

Positive intrinsic negative (PIN) diode

Integrated phtodiode/preamplifier (IDP)

18. (007) When using vertical redundancy check (VRC), what significance does the amount of ones have in a data bit pattern?

Determines parity

Determines transmission rate

Determines whether transmission is in American Standard code for Information Interchange(ASCII) format

Determines whether transmission is synchronous or asynchronous

19. (007) What error detection method adds stacked characters, divides it by 255, and disregards the answer except for the remainder?

Checksum

Block check character

Redundant data transfer

Automatic retransmit on request

20. (008) What does an optical source do?

Terminates fiber optics cable

Converts electrical energy into optical energy

Extend the distance and to preserve signal integrity

Accepts optical signals and converts them into electrical signals

21. (008) Light sources that are applicable to fiber optic waveguide are light-emitting diodes (LED) and?

Photo transistors.

Hybrid photodiodes

Semiconductor laser diodes

Integrated photodiode/preamplifiers

22. (009) Small current that flows from a photodiode even with no light is called?

Dark current

Dispersion

Distortion

Ionization

23. (010) Which repeater amplifies optical signal without converting to and from the electrical domain?

Repeaters

Regenerators

Optical Amplifiers

Receiver

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

Biconic

Field connector (FC)

Straight tip (ST)

Sub-miniature, type A (SMA)

25. (004) In phase modulation (PM), the carrier's?

Phase is shifted at the rate of the modulating signal

Phase shifted with the phase of the modulating signal

Amplitude is shifted at the rate of the modulating signal

Amplitude is shifted with the phase of the modulating signal

26. (002) Reducing modulation to less than 100 percent gives?

More total power

A reduction in carrier power

No reduction in carrier power

A reduction in carrier and sideband power

27. (003) In frequency modulation (FM), the amount of oscillator frequency change is?

Inversely proportional to the amplitude of the modulating signal.

Directly proportional to the amplitude of the modulating signal

Inversely proportional to the phase of the modulating signal

Directly proportional to the phase of the modulating signal

28. (005) What is the first step in the pulse code modulation (PCM) process?

Discrete amplitudes are assigned to the sampling pulses

A binary code number is assigned to the sample

The quantizer limits the amplitude of the pulses

The analog signal is band-limited

29. (011) Short sections of single fiber cables that has a connector at each end is called a?

Pigtail

Patch cord

Jumper

Breakout cables

30. (006) If an error should occur, what data transmission is lost in a synchronous transmission?

One Character

Block of data

A parity bit

Synchronization (SYNC) bit

31. (007) What two error detection methods, when used together, are 98 percent effective in detecting errors?

Checksum and cyclic redundancy check

Longitudinal redundancy check and checksum

Cyclic redundancy check and vertical redundancy check

Vertical redundancy check and longitudinal redundancy check

32. (004) What is the advantage of adding more phase shifts?

Easier detection

Smaller bit error rate

Better signal-to-noise ratio

Higher data rates within a given bandwidth

33. (009) The responsivity of a photo detector is dependent on the?

Emitter rise time

Wavelength of light

Signal-to-noise ratio (SNR)

Emitter modulation speed

34. (009) A device that accepts optical signals from an optical fiber and coverts them into electrical signals is called an optical?

Regenerator

Transmitter

Amplifier

Receiver

35. (009) What are the two main types of photodetectors?

Positive intrinsic negative and avalanche photodiode

Light-emitting diode (LED) and avalanche photodiode

LED and semiconductor laser

Tunnel and zener diodes

36. (007) What error-correction technique sends a retransmittal request by the receiver to the sender if it finds an error in a received frame?

Error-correcting code

Forward error control

Redundant data transfer

Automatic retransmit on request

37. (011) Which fiber optic connector uses a push-pull engagement for mating?

Biconic

Field Connector (FC)

Subscriber (SC)

Sub-mini, Type A (SMA0

Vol1 Ure1 CDC 3D153