fundcom/electronics/eelectrical equipment

Which of the following characteristics of a sine wave can be modulated?

• amplitude

• angular phase

• angular velocity

• all of these

The following are advantages of modulation except

• allow the use of practical-size antenna

• separate differing transmission

• circuit simplicity

• overcomes difficulty in transmission at low frequencies

Amplitude modulation generated at a very low voltage or power amplifier is

modulation.

• minimum

• collector

• high-level

• low-level

In AM, carrier amplitude variation depends on modulating signal's

• amplitude

• frequency

• amplitude and frequency

• none of these

A 400 watts carrier is modulated to a depth of 75 percent. Calculate the total power in the modulated wave.

• 512.5 W

• 500 W

• 530 W

• 515.5 W

If the receive signal is 600 kHz in an AM broadcast, what is the local oscillator frequency?

• 600 kHz

• 145 kHz

• 1055 kHz

• 455 kHz

The instantaneous voltage of modulated FM carrier is given by v = 10 sin (750x10 t + 10 sin 1000t). The carrier frequency is

• 750 MHz

• 1000 MHz

• 119.37 MHz

• 1000 Hz

The amount of frequency deviation from the carrier center of frequency in an FM transmitter

is proportional to the

• shape

• amplitude

• frequency

• phase

What is the common unit of the sound absorption coefficient?

• watt

• erg

• sabine

• decibel

The input is 0.1 W and the network gain is 13 dB, the output is

• 2.0 W

• 2.5 W

• 1.5 W

• 1.8 W