EASY

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Transmission efficiency of an amplitude modulation wave is the ratio of the transmitted power which contains the information to the total transmitted power.This statement is true or false?

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Important Questions on Communication Systems

HARD

Physics>Modern Physics>Communication Systems>Modulation and Demodulation

The modulation frequency of an

A M

radio station is

250 kHz,

which is

10 %

of the carrier wave. If another

A M

station approaches you for license what broadcast frequency will you allot?

MEDIUM

Physics>Modern Physics>Communication Systems>Modulation and Demodulation

A message signal of frequency

100 M H z

and peak voltage

100 V

is used to execute amplitude modulation on a carrier wave of frequency

300 G H z

and peak voltage

400 V

. The modulation index and difference between the two side band frequencies are:

EASY

Physics>Modern Physics>Communication Systems>Modulation and Demodulation

A carrier signal of frequency

v_{1}

and peak voltage of

V_{1}

is modulated by a message signal of frequency

v_{2}

and peak voltage of

V_{2}

. Let

m

be the modulation index and

v_{+}, v_{-}

be side bands produced. The correct statement is

MEDIUM

Physics>Modern Physics>Communication Systems>Modulation and Demodulation

A carrier wave of peak voltage

20 V

is used to transmit a message signal. For getting a modulation index of

60 %

, the peak voltage of the modulating signal is

MEDIUM

Physics>Modern Physics>Communication Systems>Modulation and Demodulation

A signal of frequency

20 kHz

and peak voltage of

5 Volt

is used to modulate a carrier wave of frequency

1.2 MHz

and peak voltage

25 Volts

. Choose the correct statement.

EASY

Physics>Modern Physics>Communication Systems>Modulation and Demodulation

A signal of frequency

3 kHz

is amplitude modulated on a carrier wave of frequency

2.5 MHz .

The upper and lower sideband frequencies in the resultant signal are

EASY

Physics>Modern Physics>Communication Systems>Modulation and Demodulation

In amplitude modulation of audio frequency

700 Hz

, the appropriate carrier frequency to be used is

EASY

Physics>Modern Physics>Communication Systems>Modulation and Demodulation

Identify the correct statement among the following.

EASY

Physics>Modern Physics>Communication Systems>Modulation and Demodulation

Choose the correct statement:

HARD

Physics>Modern Physics>Communication Systems>Modulation and Demodulation

A modulated signal

C_{m} (t)

has the form

C_{m} (t) = 30 \sin 300 π t + 10 (\cos 200 π t - \cos 400 π t) .

The carrier frequency

f_{c}

, the modulating frequency (message frequency)

f_{m ,}

and the modulation index

μ

are respectively given by :

EASY

Physics>Modern Physics>Communication Systems>Modulation and Demodulation

If the maximum and minimum values of an amplitude modulated signals are respectively

5.9 V

and

1.2 V,

the modulation index of the signal is

HARD

Physics>Modern Physics>Communication Systems>Modulation and Demodulation

A signal of $5 kHz$ frequency is amplitude modulated on a carrier wave of frequency $2 MHz$ . The frequencies of the resultant signal is/are:

EASY

Physics>Modern Physics>Communication Systems>Modulation and Demodulation

If the maximum and the minimum amplitudes of an amplitude modulated wave are

25 V

and

5 V

respectively, then the modulation index is

EASY

Physics>Modern Physics>Communication Systems>Modulation and Demodulation

A message signal

15 \sin (100 π t)

is used to modulate a carrier signal

45 \sin (3 \times 10^{6} π t) .

The modulation index is

MEDIUM

Physics>Modern Physics>Communication Systems>Modulation and Demodulation

A signal of frequency

20 kHz

and peak voltage

10 V

is used in the amplitude modulation of a carrier wave of frequency

0.5 MHz

and peak voltage

20 V

. Then the ratio of the frequencies of upper side band to the lower side band is

EASY

Physics>Modern Physics>Communication Systems>Modulation and Demodulation

A message signal of frequency

10 kHz

and peak value of

10 volts

is used to moderate a carrier of frequency

1 MHz

and peak voltage

20 volts .

The modulation index and side bands produced are

EASY

Physics>Modern Physics>Communication Systems>Modulation and Demodulation

For an amplitude modulated wave, the maximum amplitude is found to be

12 V

while the minimum amplitude is found to be

4 V

. The modulation index

μ

will be

EASY

Physics>Modern Physics>Communication Systems>Modulation and Demodulation

In a

CE

transistor amplifier, the audio signal voltage across the collector resistance of

2 kΩ

2 V

, if the base resistance is

1 kΩ

and the current amplification of the transistor is

100

then the input signal voltage is

EASY

Physics>Modern Physics>Communication Systems>Modulation and Demodulation

In amplitude modulation, the sinusoidal carrier frequency used is denoted by

ω_{c}

and the signal frequency is denoted by

ω_{m}

. The bandwidth

(Δ ω_{m})

of the signal is such that

Δ ω_{m} ≪ ω_{c}

. Which of the following frequencies is not contained in the modulated wave?

HARD

Physics>Modern Physics>Communication Systems>Modulation and Demodulation

A diode detector is used to detect an amplitude modulated wave of 60% modulation by using a condenser of capacity 250 pico farad in parallel with a load resistance of 100 kilo ohm. Find the maximum modulated frequency which could be detected by it.

Transmission efficiency of an amplitude modulation wave is the ratio of the transmitted power which contains the information to the total transmitted power.This statement is true or false?

Important Questions on Communication Systems

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