Study Guide Questions about Noise

• What is the name of the noise from random acoustic or electric noise that has equal per cycle over a specified total frequency band?

a. Thermal noise
b. Gaussian noise
c. White noise
d. All of these

• What is the reliable measurement for comparing amplifier noise characteristics?

a. Thermal agitation noise
b. Noise margin
c. Noise factor
d. Signal-to-noise

• What is measured on a circuit when it is coorectky terminated but does not have any traffic?

a. White noise
b. Extraterrestial noise
c. Industrial noise
d. Atmospheric noise

• Man-made noise is usually from

a. transmission over power lines and by ground-wave
b. sky-wave
c. space-wave
d. troposphere

• Which one of the following is not a useful quantity for comparing the noise performance of receivers?

a. Input noise voltage
b. Equivalent noise resistance
c. Noise temperature
d. Noise figure

• For best reception, what is S/N ?

a. Low
b. High
c. Zero
d. Unity

• What is the source of the most internal noise problems ?

a. Skin Effect
b. Thermal agitation
c. Shot effect
d. Transit-time Effect

• In measuring noise in a voice channel at a -4dB test point level, the meter reads -70 dBm. Convert the reading into dBa, F1A Weighted.

a. 12
b. 16
c. 15
d. 19

• What is the primary source of space noise ?

a. Sun
b. Stars
c. Galaxies
d. Lightning

• What theorem sets a limit on the maximum capacity of a channel with a given noise level?

a. Nyquist theorem
b. Shannon-Hartley theorem
c. Hartley Law
d. Shannon theorem

• You are measuring a voice channel at a +4dB test point level, the meter reads -73 dBm (pure test tone). Convert the reading into dBmCO.

a. 13
b. 18
c. 16
d. 21