Ans. That form of detection in which the audio output voltage under consideration is substantially proportional to the modulation envelope throughout the useful range of the detecting device.
Describe and give the function of a loading coil.
Ans. An inductor inserted in a circuit to increase its inductance but not to provide coupling with any other circuit.
What is generally meant by a loud speaker?
Ans. A telephone receiver or apparatus designed to radiate acoustic power into a room or open air.
What is meant by a magnetic loud speaker?
Ans. One in which the mechanical forces result from magnetic reactions.
What is a magnetic microphone?
Ans. A microphone whose electrical output results from the motion of a coil or conductor in a magnetic field.
Describe a master oscillator.
Ans. An oscillator of comparatively low power so arranged as to establish the carrier frequency of the output of an amplifier.
How many cycles per second is one megacycle?
Ans. When used as a unit of frequency, it is one million cycles per second.
Ans. A mercury-vapor rectifier is a two electrode, vacuum-tube rectifier which contains a small amount of mercury . During operation, the mercury is vaporized. A characteristic of mercury-vapor rectifiers is the low voltage drop in the tube.
Ans. A microphone is an electro-acoustic transducer actuated by power in an acoustic system and delivering power to an electric system, the wave form in the electric system corresponding to the wave form in the acoustic system. This is also called a telephone transmitter.
What is generally understood by a "Mixer tube" in superheterodyne receivers?
Ans. A mixer tube is one in which a locally generated frequency is combined with the carrier signal frequency to obtain a desired beat frequency.
What is a modulated wave?
Ans. A wave of which either the amplitude, frequency or phase is varied in accordance with a signal.
Ans. Modulation is the process in which the amplitude, frequency or phase of a wave is varied in accordance with a signal, or the result of that process.
Describe what is meant by monochromatic sensitivity.
Ans. The response of a phototube to light of a given color, or narrow frequency range.
What is ai moving-armature speaker?
, Ans. A magnetic speaker whose operation involves the vibration of a portion of the ferromagnetic circuit. This is sometimes called an electromagnetic or a magnetic speaker.
Ans. A moving coil loud speaker is a magnetic loud speaker in which the mechanical forces are developed by the interaction of currents in a conductor and the polarizing field in which it is located. This is sometimes called an electro-dynamic or a dynamic loud speaker.
What is meant by Mu-factor?
Ans. A measure of the relative effect of the voltages on two electrodes upon the current in the circuit of any specified electrode. It is the ratio of the change in one electrode voltage to a change in the other electrode voltage, under the condition that a specified current remains unchanged.
What is an oscillator?
Ans. A non-rotating device for producing alternating current, the output frequency of which is determined by the characteristics of the device.
Describe an oscillatory circuit. ,
Ans. A circuit containing inductance and capacitance, such that a voltage impulse will produce a current which periodically reverses.
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