What is the need for a tuned amplifier?

What is the need for a tuned amplifier?
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1 Answer

Answer :

In radio or TV receivers , it is necessary to select a particular channel among all other available channels.Hence some sort of frequency selective circuit is needed that will allow us to amplify the frequency band required and reject all the other unwanted signals and this function is provided by a tuned amplifier.
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Related questions

Give the classification of tuned amplifier

Description : Give the classification of tuned amplifier

Last Answer : (i) Small signal tuned amplifier *Single tuned *Double tuned *Stagger tuned (ii) Large signal tuned amplifier.

State the need of tuned amplifier in electronic circuits.

Description : State the need of tuned amplifier in electronic circuits.

Last Answer : Necessity of tuned amplifier: 1. Selection of the desired radio frequency signal. 2. Amplification of the selected signal to a selected voltage level.

An FM receiver whose intermediate frequency is 10.7 MHz, is experiencing image channel interference from a station transmitting on 121.1 MHz. If the local oscillator is tracking above, the receiver is tuned to A. 131.8 MHz B. 110.4 MHz C. 142.5 MHz D. 99.7 MHz

Description : An FM receiver whose intermediate frequency is 10.7 MHz, is experiencing image channel interference from a station transmitting on 121.1 MHz. If the local oscillator is tracking above, the receiver is tuned to A. 131.8 MHz B. 110.4 MHz C. 142.5 MHz D. 99.7 MHz

Last Answer : D. 99.7 MHz

A superhet receiver has an IF of 455 kHz and is experiencing image-channel interference on a frequency of 1570 kHz. The receiver is tuned to A. 1115 kHz B. 660 kHz C. 2025 kHz D. 910 kHz

Description : A superhet receiver has an IF of 455 kHz and is experiencing image-channel interference on a frequency of 1570 kHz. The receiver is tuned to A. 1115 kHz B. 660 kHz C. 2025 kHz D. 910 kHz

Last Answer : B. 660 kHz

Which of the following methods cannot be used to increase the bandwidth for cascaded RF amplifier stages? A) Wave traps in each stage B) Stagger tuning C) A shunt damping resistor across each tuned circuit D) Doubled tuned transformers with tighter coupling

Description : Which of the following methods cannot be used to increase the bandwidth for cascaded RF amplifier stages? A) Wave traps in each stage B) Stagger tuning C) A shunt damping resistor across each tuned circuit D) Doubled tuned transformers with tighter coupling

Last Answer : A) Wave traps in each stage

Which of the following circuit would be preferred for a 455 kHz IF amplifier? A) A resistance loaded B) Double tuned transformer C) Video amplifier D) Class C

Description : Which of the following circuit would be preferred for a 455 kHz IF amplifier? A) A resistance loaded B) Double tuned transformer C) Video amplifier D) Class C

Last Answer : B) Double tuned transformer

Sketch the single tuned amplifier.

Description : Sketch the single tuned amplifier.

Last Answer : single tuned amplifier

Draw the circuit of single tuned amplifier and state its operating principle.

Description : Draw the circuit of single tuned amplifier and state its operating principle.

Last Answer : Operating Principle: The working of tuned voltage amplifier may be understood by considering a radio frequency signal, to be amplified applied at the input of the amplifier. The resonant frequency ... will be amplified. And all the other frequencies will be rejected by the tuned circuit. 

Explain stagger tuned amplifier with the help of waveforms.

Description : Explain stagger tuned amplifier with the help of waveforms.

Last Answer : Circuit Diagram: Above figure shows two-stage tuned voltage amplifier. The stagger tuning in this circuit, may be achieved by resonating the tuned circuits L1C1 and L2C2 to slightly different ... outside the pass-band. Because of the stagger tuning there is a loss of voltage gain.

Describe the operation of double tuned amplifier with the help of neat circuit diagram and mention its applications.

Description : Describe the operation of double tuned amplifier with the help of neat circuit diagram and mention its applications.

Last Answer : Circuit diagram: Operation:  *The signal to be amplified is applied at the input terminal through the coupling capacitor CC  *The resonant frequency of the tuned circuit L1 C1 is made equal ... : (i) Radio and T .V broadcasting as tuning circuit. (ii) Wireless communication system.

role of tuned LC circuit in tuned amplifier.

Description : role of tuned LC circuit in tuned amplifier.

Last Answer : In order to pick up and amplify the desired radio frequency signal, the resistive load in the audio amplifier is replaced by a tuned circuit (also called a parallel resonant circuit)as shown ... desired radio frequency signal. (ii)Amplification of the selected signal to a suitable voltage level.

What is the need for an instrumentation amplifier?

Description : What is the need for an instrumentation amplifier?

Last Answer :  In a number of industrial and consumer applications, the measurement of physical quantities is usually done with the help of transducers. The output of transducer has to be amplified So that it can drive the indicator or display system. This function is performed by an instrumentation amplifier.

Not a reason for the use of an antenna coupler. A. To make the antenna look resistive B. To provide the output amplifier with the correct load impedance C. To discriminate against harmonics D. To prevent re-radiation of the local oscillator

Description : Not a reason for the use of an antenna coupler. A. To make the antenna look resistive B. To provide the output amplifier with the correct load impedance C. To discriminate against harmonics D. To prevent re-radiation of the local oscillator

Last Answer : D. To prevent re-radiation of the local oscillator

A final amplifier of a radio transmitter draws 250 mA of plate current when the plate supply voltage is 1400 volts. If the plate circuit efficiency is 80% and the transmitter is connected to an antenna having a feed impedance of 70 ohms, what is the antenna current at the feed-point? A. 4.0 A B. 2.2 A C. 1.25 A D. 2.0 A

Description : A final amplifier of a radio transmitter draws 250 mA of plate current when the plate supply voltage is 1400 volts. If the plate circuit efficiency is 80% and the transmitter is connected to an antenna having a feed impedance of 70 ohms, ... at the feed-point? A. 4.0 A B. 2.2 A C. 1.25 A D. 2.0 A

Last Answer : D. 2.0 A

Which of the following antennas is used for testing and adjusting a transmitter for proper modulation, amplifier operation and frequency accuracy? A. Elementary B. Real C. Isotropic D. Dummy

Description : Which of the following antennas is used for testing and adjusting a transmitter for proper modulation, amplifier operation and frequency accuracy? A. Elementary B. Real C. Isotropic D. Dummy

Last Answer : D. Dummy

Which circuit contributes most of the noise in a receiver? A. IF amplifier B. Demodulator C. AF amplifier D. Mixer

Description : Which circuit contributes most of the noise in a receiver? A. IF amplifier B. Demodulator C. AF amplifier D. Mixer

Last Answer : D. Mixer

Calculate the noise figure of the receiver whose RF amplifier has an input resistance of 1000Ω and an equivalent shot-noise resistance of 2000Ω, a gain of 25 and load resistance of 125 kΩ. Given that the bandwidth is 1.0MHz and the temperature is 20˚C, and that the receiver is connected to an antenna with an impedance of 75Ω. A. 30.3 B. 3.03 C. 303 D. .303

Description : Calculate the noise figure of the receiver whose RF amplifier has an input resistance of 1000Ω and an equivalent shot-noise resistance of 2000Ω, a gain of 25 and load resistance of 125 kΩ. Given that the bandwidth is 1. ... to an antenna with an impedance of 75Ω. A. 30.3 B. 3.03 C. 303 D. .303

Last Answer : A. 30.3

Calculated the noise figure of the amplifier whose Req equals 2518Ω (RT=600Ω) if its driven by a generator whose output impedance is 50Ω. A. 39.4 B. 3.94 C. 394 D. 0.394

Description : Calculated the noise figure of the amplifier whose Req equals 2518Ω (RT=600Ω) if its driven by a generator whose output impedance is 50Ω. A. 39.4 B. 3.94 C. 394 D. 0.394

Last Answer : A. 39.4

Indicate the false statement. Noise figure is defined as A. the ratio of the S/N power supplied at the input terminal of a receiver or amplifier to the S/N power supplied to the output or load resistor B. noise factor expressed in decibels C. an unwanted form of energy tending to interfere with the proper and easy reception and reproduction of wanted signal D. S/N of an ideal system divided by S/N at the output of the receiver or amplifier under test, both working at the same temperature over the same bandwidth and fed from the same source

Description : Indicate the false statement. Noise figure is defined as A. the ratio of the S/N power supplied at the input terminal of a receiver or amplifier to the S/N power supplied to the output or ... under test, both working at the same temperature over the same bandwidth and fed from the same source

Last Answer : C. an unwanted form of energy tending to interfere with the proper and easy reception and reproduction of wanted signals

The noise output of a resistor is amplified by a noiseless amplifier having a gain of 60 and a bandwidth of 20 kHz. A meter connected at the output of the amplifier reads 1mV RMS. If the bandwidth of the amplifier is reduced to 5kHz, its gain remaining constant, what does the meter read now? A. 0.5 mV B. 0.5 µV C. 5.0 mV D. 5.0 µV

Description : The noise output of a resistor is amplified by a noiseless amplifier having a gain of 60 and a bandwidth of 20 kHz. A meter connected at the output of the amplifier reads 1mV RMS. If the bandwidth of the amplifier is reduced to ... does the meter read now? A. 0.5 mV B. 0.5 µV C. 5.0 mV D. 5.0 µV

Last Answer : A. 0.5 mV

The first stage of a two-stage amplifier has a voltage gain of 10, a 600 Ω input resistor, a 1600Ω equivalent noise resistance and 27kΩ output resistor. For the second stage, these values are 25, 81kΩ, 19kΩ, and 1MΩ, respectively. Calculate the equivalent input-noise resistance of this two stage amplifier. A. 2,518 kΩ B. 2,518 Ω C. 251.8 Ω D. 12,518 Ω

Description : The first stage of a two-stage amplifier has a voltage gain of 10, a 600 Ω input resistor, a 1600Ω equivalent noise resistance and 27kΩ output resistor. For the second stage, these values are 25, 81kΩ, 19kΩ, and 1MΩ, ... this two stage amplifier. A. 2,518 kΩ B. 2,518 Ω C. 251.8 Ω D. 12,518 Ω

Last Answer : B. 2,518 Ω

An amplifier operating over the frequency range of 455 to 460 kHz has a 200 kΩ input resistor. What is the RMS noise voltage at the input to this amplifier if the ambient temperature is 17˚C ? A. 40 µV B. 4.0 µV C. 400 µV

Description : An amplifier operating over the frequency range of 455 to 460 kHz has a 200 kΩ input resistor. What is the RMS noise voltage at the input to this amplifier if the ambient temperature is 17˚C ? A. 40 µV B. 4.0 µV C. 400 µV

Last Answer : B. 4.0 µV

What is the reliable measurement for comparing amplifier noise characteristics? A. Thermal agitation noise B. Noise factor C. Noise margin D. Signal-to-noise

Description : What is the reliable measurement for comparing amplifier noise characteristics? A. Thermal agitation noise B. Noise factor C. Noise margin D. Signal-to-noise

Last Answer : B. Noise factor

What part or section of a TV receiver that separates the sound and video signals? A. IF stage B. Video amplifier C. Video detector D. Burst separator

Description : What part or section of a TV receiver that separates the sound and video signals? A. IF stage B. Video amplifier C. Video detector D. Burst separator

Last Answer : C. Video detector

When measuring a transmitter’s frequency against a suitable standard, the frequency to be measured is taken from the A. oscillator stage B. intermediate amplifier C. buffer stage D. final RF stage

Description : When measuring a transmitter’s frequency against a suitable standard, the frequency to be measured is taken from the A. oscillator stage B. intermediate amplifier C. buffer stage D. final RF stage

Last Answer : D. final RF stage

What is the meaning of forward power? A. The power traveling from the transmitter to the antenna. B. The power radiated from the top of an antenna system. C. The power produced during the positive half of an RF cycle. D. The power used to drive a linear amplifier.

Description : What is the meaning of forward power? A. The power traveling from the transmitter to the antenna. B. The power radiated from the top of an antenna system. C. The power produced during the positive half of an RF cycle. D. The power used to drive a linear amplifier.

Last Answer : A. The power traveling from the transmitter to the antenna.

What establishes the receiver bandwidth? A. RF amplifier B. Mixer C. Local oscillator D. IF amplifier

Description : What establishes the receiver bandwidth? A. RF amplifier B. Mixer C. Local oscillator D. IF amplifier

Last Answer : D. IF amplifier

What consists the front-end circuit of a VHF TV superheterodyne receiver? A. Mixer, RF amplifier and AFC? B. RF amplifier, Band pass filter and mixer C. Local oscillator, mixer and RF amplifier D. Local oscillator, AGC and antenna

Description : What consists the front-end circuit of a VHF TV superheterodyne receiver? A. Mixer, RF amplifier and AFC? B. RF amplifier, Band pass filter and mixer C. Local oscillator, mixer and RF amplifier D. Local oscillator, AGC and antenna

Last Answer : C. Local oscillator, mixer and RF amplifier

One of the following is a high powered RF ac basic transmitter that has two or more stages, the oscillator stage which determines the frequency opereation and RF amplifier stage orstages that develop the high power output. The purpose of which is to develop a good frequency stability. A. Goldsmith B. MOPA C. Alexanderson D. Hartley

Description : One of the following is a high powered RF ac basic transmitter that has two or more stages, the oscillator stage which determines the frequency opereation and RF amplifier stage orstages that develop the ... to develop a good frequency stability. A. Goldsmith B. MOPA C. Alexanderson D. Hartley

Last Answer : B. MOPA

Determine the lower half-power frequency of a class-C amplifier having upper half-power frequency of 10.025 MHz, a resonant frequency 5 MHz and a circuit Q of 10. A. 1.0025 MHz B. 10.525 MHz C. 0.5 MHz D. 10 MHz

Description : Determine the lower half-power frequency of a class-C amplifier having upper half-power frequency of 10.025 MHz, a resonant frequency 5 MHz and a circuit Q of 10. A. 1.0025 MHz B. 10.525 MHz C. 0.5 MHz D. 10 MHz

Last Answer : A. 1.0025 MHz

Which of the following parts of the radio receiver represent the component that extracts the desire RF signal from the electromagnetic wave? A. AF amplifier B. Antenna C. Detector D. Crystal

Description : Which of the following parts of the radio receiver represent the component that extracts the desire RF signal from the electromagnetic wave? A. AF amplifier B. Antenna C. Detector D. Crystal

Last Answer : B. Antenna

One of the following is a possible cause of an abrupt frequency variation in a self exited transmitter oscillator circuits resulting to a poor frequency stability to hold a constant frequency oscillation. A. Heating and expansion of oscillator coil B. DC and RF ac heating of resistors which cause change in values C. Heating of capacitor in the oscillatorD. Loose connections in the oscillator, amplifier, or antenna circuits.

Description : One of the following is a possible cause of an abrupt frequency variation in a self exited transmitter oscillator circuits resulting to a poor frequency stability to hold a constant frequency ... capacitor in the oscillator D. Loose connections in the oscillator, amplifier, or antenna circuits.

Last Answer : D. Loose connections in the oscillator, amplifier, or antenna circuits.

Refers to one of the front end circuit of a VHF TV superheterodyne receiver which is usually a separate circuit coupled to the mixer. A. Antenna feed B. AGC C. RF amplifier D. Local oscillator

Description : Refers to one of the front end circuit of a VHF TV superheterodyne receiver which is usually a separate circuit coupled to the mixer. A. Antenna feed B. AGC C. RF amplifier D. Local oscillator

Last Answer : D. Local oscillator

Referred to an oscillator signal “leak through” from a properly neutralized amplifier such as a master oscillator power amplifier. A. Carrier B. Stray signal C. Back wave D. Loss wave

Description : Referred to an oscillator signal “leak through” from a properly neutralized amplifier such as a master oscillator power amplifier. A. Carrier B. Stray signal C. Back wave D. Loss wave

Last Answer : C. Back wave

Which of the following is one of the possible causes for a slow drift of frequency in a self exited transmitter oscillator circuits resulting to a poor frequency stability? A. Poor soldered connections B. Power supply voltage changes C. Loose connections in the oscillator, amplifier, or antenna circuits D. DC and RF heating of resistors, causing then to change values.

Description : Which of the following is one of the possible causes for a slow drift of frequency in a self exited transmitter oscillator circuits resulting to a poor frequency stability? A. Poor soldered connections ... , or antenna circuits D. DC and RF heating of resistors, causing then to change values.

Last Answer : D. DC and RF heating of resistors, causing then to change values.

Referred to as the stage in the radio receiver that contributes most of the noise. A. IF amplifier B. Supply stage C. Speaker D. Mixer

Description : Referred to as the stage in the radio receiver that contributes most of the noise. A. IF amplifier B. Supply stage C. Speaker D. Mixer

Last Answer : D. Mixer

Best describe as an amplifier used in radio telephony. A. Magnifier B. Class B C. Class C D. Class A

Description : Best describe as an amplifier used in radio telephony. A. Magnifier B. Class B C. Class C D. Class A

Last Answer : C. Class C

What do you call the single booster installed on the antenna dish of satellite receiver? A. Low noise amplifier B. Single amplifier C. Noise amplifier D. Rectifier

Description : What do you call the single booster installed on the antenna dish of satellite receiver? A. Low noise amplifier B. Single amplifier C. Noise amplifier D. Rectifier

Last Answer : A. Low noise amplifier

How can intermodulation interference between two transmitters in close proximity reduced or eliminated? A. Through installing a band-pass filter in the antenna feed line B. Through installing terminated circulator or ferrite isolator in the feed line of the transmitter and duplexer C. By using a class C final amplifier with high driving power D. By installing a low-pass filter in the antenna feed line

Description : How can intermodulation interference between two transmitters in close proximity reduced or eliminated? A. Through installing a band-pass filter in the antenna feed line B. Through installing terminated circulator ... high driving power D. By installing a low-pass filter in the antenna feed line

Last Answer : A. Through installing a band-pass filter in the antenna feed line

The final power amplifier in an FM transmitter usually operates class ______. A. AB B. C C. B D. A

Description : The final power amplifier in an FM transmitter usually operates class ______. A. AB B. C C. B D. A

Last Answer : B. C

The final amplifier of either FM or AM transmitter operates as A. Class B B. Class C C. Class A D. Class D

Description : The final amplifier of either FM or AM transmitter operates as A. Class B B. Class C C. Class A D. Class D

Last Answer : B. Class C

Define non-inverting amplifier?

Description : Define non-inverting amplifier?

Last Answer : The input is applied to the non-inverting input terminal and the inverting terminal connected to the ground.

List the applications of instrumentation amplifier.

Description : List the applications of instrumentation amplifier.

Last Answer : a. Temperature indicator b. Temperature controller c. Light intensity meters d. Water flow meter c. Thermal conductivity meter f. Analog weight scale

What is the type of feedback employed in the inverting op-amp amplifier?

Description : What is the type of feedback employed in the inverting op-amp amplifier?

Last Answer : Negative feedback is employed in the inverting op-amp amplifier.

Which feedback increases the gain of the amplifier?

Description : Which feedback increases the gain of the amplifier?

Last Answer : Positive feedback

Which feedback decreases the gain of the amplifier?

Description : Which feedback decreases the gain of the amplifier?

Last Answer : Negative feed back

How can a AC equivalent circuit of a amplifier be obtained?

Description : How can a AC equivalent circuit of a amplifier be obtained?

Last Answer : By replacing dc supply by a ground and short- circuiting capacitors.

How can a DC equivalent circuit of an amplifier be obtained?

Description : How can a DC equivalent circuit of an amplifier be obtained?

Last Answer : By open circuiting the capacitor.