NAVEDTRA 14181A, NAVY ELECTRICITY AND ELECTRONICS TRAINING SERIES, MODULE 9- WAVE GENERATION AND WAVE SHAPING

Question 1

What can be regarded as an amplifier which provides its own input signal?

Answer 1

Oscillator

Question 2

Which two broad categories according to their output waveshapes can wave generators be classified into?

Answer 2

Sinusoidal and Nonsinusoidal

Question 3

Which type of oscillator produces a sine-wave output signal?

Answer 3

Sinusoidal

Question 4

Many low-frequency generators use resistors and capacitors to form their frequency-determining networks and are referred to as what?

Answer 4

RC Oscillators

Question 5

Which type of sine-wave generator uses inductors and capacitors for its frequency-determining network?

Answer 5

LC Oscillator

Question 6

Which type of oscillator provides excellent frequency stability and is used from the middle of the audio range through the radio frequency range?

Answer 6

Crystal controlled

Question 7

Which type of oscillators generate complex waveforms, such as square, rectangular, trigger, sawtooth, or trapezoidal?

Answer 7

Nonsinusoidal

Question 8

Which device acts as a filter, allowing only the desired frequency to pass?

Answer 8

Frequency-determining

Question 9

Which two stability requirements does virtually every piece of equipment that uses an oscillator have?

Answer 9

Amplitude and Frequency

Question 10

What provides isolation between the oscillator and the load to prevent changes in the load from affecting the oscillator?

Answer 10

Buffer

Question 11

Which class of bias may oscillators use when a high efficiency is not required but distortion must be kept at a minimum?

Answer 11

Class A

Question 12

An amplifier can be made into a sine-wave oscillator by providing what through an RC network?

Answer 12

Regenerative feedback

Question 13

What is the reduction of amplitude in an oscillator circuit referred to as?

Answer 13

Damping

Question 14

What is the maintenance of oscillations in a circuit in the intervals between pulses of excitation energy?

Answer 14

Flywheel effect

Question 15

What is the property of a crystal by which mechanical forces produce electrical charges and, conversely, electrical charges produce mechanical forces?

Answer 15

Piezoelectric effect

Question 16

What is the frequency for which a crystal is ground referred to as?

Answer 16

Natural resonant frequency

Question 17

Commercially produced crystals range in Q from 5,000 to what?

Answer 17

30,000

Question 18

In both tube and transistor oscillators, which circuit couples energy of the proper amount and of the correct phase from the output to the input circuit to sustain oscillations?

Answer 18

Feedback

Question 19

What is the process of transferring energy from a high-level point in a system to a low-level point in a system?

Answer 19

Feedback

Question 20

What is one of the requirements to sustain oscillations in an oscillator?

Answer 20

Positive feedback

Question 21

What is an oscillator in which DC power for the transistor through the tank circuit, or a portion of the tank circuit said to be?

Answer 21

Series fed

Question 22

Which type of oscillator receives its DC power for the transistor through a path separate and parallel to the tank circuit said to be?

Answer 22

Shunt fed

Question 23

What property of an oscillator is a measure of the degree to which a constant frequency output is approached?

Answer 23

Frequency stability

Question 24

What is a prime requirement for good frequency stability?

Answer 24

Constant supply voltage

Question 25

What property of a transistor oscillator indicates the amount by which the actual output amplitude varies from the desired output amplitude?

Answer 25

Amplitude stability

Question 26

What is used to produce a sine-wave output of constant amplitude and of fairly constant frequency within the rf range?

Answer 26

Armstrong oscillator

Question 27

Which oscillator is very similar to the shunt-fed Hartley oscillator, except that two capacitors are used in the tank circuit instead of a tapped coil?

Answer 27

Colpitts

Question 28

Which type of oscillator is usually used to produce an output which is highly stable and at a very precise frequency?

Answer 28

Crystal-controlled

Question 29

What do transmitters that require a very high degree of frequency stability use to maintain a constant crystal temperature?

Answer 29

Temperature-controlled ovens

Question 30

The amount of current that can safely pass through a crystal ranges from 50 to how many milliamperes?

Answer 30

200

Question 31

The Q of a crystal may be more than how many times greater than that obtained with an equivalent electrical circuit?

Answer 31

100

Question 32

Commercially produced crystals range in Q from 5,000 to 30,000 while some laboratory experiment crystals range in Q up to what?

Answer 32

400,000

Question 33

Which type of oscillator will produce output pulses at a predetermined frequency for an indefinite period of time?

Answer 33

Sinusoidal (sine-wave)

Question 34

What is defined as a sinusoidal wave having a frequency that is a multiple of the fundamental frequency?

Answer 34

Harmonics

Question 35

What is a sine wave that is twice the fundamental frequency referred to as?

Answer 35

Second harmonic

Question 36

The second harmonic of a fundamental frequency has only what percent of the amplitude of the resonant frequency?

Answer 36

20

Question 37

Frequency multipliers are pecial class C amplifiers that are biased at 3 to how many times the normal cutoff bias?

Answer 37

10

Question 38

What decreases the loading effect on the oscillator by reducing the interaction (matching impedance) between the load and the oscillator?

Answer 38

Buffer amplifier

Question 39

What is used to produce a sine-wave output of constant amplitude and fairly constant frequency?

Answer 39

Hartley oscillator