NAVEDTRA 14181A, NAVY ELECTRICITY AND ELECTRONICS TRAINING SERIES, MODULE 9- WAVE GENERATION AND WAVE SHAPING Flashcards
What can be regarded as an amplifier which provides its own input signal?
Oscillator
Which two broad categories according to their output waveshapes can wave generators be classified into?
Sinusoidal and Nonsinusoidal
Which type of oscillator produces a sine-wave output signal?
Sinusoidal
Many low-frequency generators use resistors and capacitors to form their frequency-determining networks and are referred to as what?
RC Oscillators
Which type of sine-wave generator uses inductors and capacitors for its frequency-determining network?
LC Oscillator
Which type of oscillator provides excellent frequency stability and is used from the middle of the audio range through the radio frequency range?
Crystal controlled
Which type of oscillators generate complex waveforms, such as square, rectangular, trigger, sawtooth, or trapezoidal?
Nonsinusoidal
Which device acts as a filter, allowing only the desired frequency to pass?
Frequency-determining
Which two stability requirements does virtually every piece of equipment that uses an oscillator have?
Amplitude and Frequency
What provides isolation between the oscillator and the load to prevent changes in the load from affecting the oscillator?
Buffer
Which class of bias may oscillators use when a high efficiency is not required but distortion must be kept at a minimum?
Class A
An amplifier can be made into a sine-wave oscillator by providing what through an RC network?
Regenerative feedback
What is the reduction of amplitude in an oscillator circuit referred to as?
Damping
What is the maintenance of oscillations in a circuit in the intervals between pulses of excitation energy?
Flywheel effect
What is the property of a crystal by which mechanical forces produce electrical charges and, conversely, electrical charges produce mechanical forces?
Piezoelectric effect
What is the frequency for which a crystal is ground referred to as?
Natural resonant frequency
Commercially produced crystals range in Q from 5,000 to what?
30,000
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?
Feedback
What is the process of transferring energy from a high-level point in a system to a low-level point in a system?
Feedback
What is one of the requirements to sustain oscillations in an oscillator?
Positive feedback
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?
Series fed
Which type of oscillator receives its DC power for the transistor through a path separate and parallel to the tank circuit said to be?
Shunt fed
What property of an oscillator is a measure of the degree to which a constant frequency output is approached?
Frequency stability
What is a prime requirement for good frequency stability?
Constant supply voltage
What property of a transistor oscillator indicates the amount by which the actual output amplitude varies from the desired output amplitude?
Amplitude stability
What is used to produce a sine-wave output of constant amplitude and of fairly constant frequency within the rf range?
Armstrong oscillator
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?
Colpitts
Which type of oscillator is usually used to produce an output which is highly stable and at a very precise frequency?
Crystal-controlled
What do transmitters that require a very high degree of frequency stability use to maintain a constant crystal temperature?
Temperature-controlled ovens
The amount of current that can safely pass through a crystal ranges from 50 to how many milliamperes?
200
The Q of a crystal may be more than how many times greater than that obtained with an equivalent electrical circuit?
100
Commercially produced crystals range in Q from 5,000 to 30,000 while some laboratory experiment crystals range in Q up to what?
400,000
Which type of oscillator will produce output pulses at a predetermined frequency for an indefinite period of time?
Sinusoidal (sine-wave)
What is defined as a sinusoidal wave having a frequency that is a multiple of the fundamental frequency?
Harmonics
What is a sine wave that is twice the fundamental frequency referred to as?
Second harmonic
The second harmonic of a fundamental frequency has only what percent of the amplitude of the resonant frequency?
20
Frequency multipliers are pecial class C amplifiers that are biased at 3 to how many times the normal cutoff bias?
10
What decreases the loading effect on the oscillator by reducing the interaction (matching impedance) between the load and the oscillator?
Buffer amplifier
What is used to produce a sine-wave output of constant amplitude and fairly constant frequency?
Hartley oscillator
