Noise and dB

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Which of the following crystal is commonly used in microphones

Quartz

Rochelle salt (correct)

Tournaline

ADP

The Theory of radio waves was orginated by:

Bell

Maxwell (correct)

Hertz

Marconi

Which of the steps is not included in the process of reception?

Encoding (correct)

Storage

Interpretation

Decoding

Man-made noise is cause by

Arc discharges in electrical machines Signup and view all the answers

Standard design reference for environmental noise temperature

290K Signup and view all the answers

Standardized as the amplitude of the carrier voltage modulated 30% by 400Hz signal which when applied to the receiver input through a standard antenna will develop an output of 0.5W in a resistive load

Sensitivity Signup and view all the answers

_______ is measured on a circuit when it is correctly terminated but does not have any traffic

White Noise Signup and view all the answers

Distortion is caused by

All of the above Signup and view all the answers

Which of broad classifications of noise are most difficult to treat?

noise generated in the receiver Signup and view all the answers

The most common unit of noise measurement in white noise voltage testing

NPR Signup and view all the answers

The difference between signal strength at a given point and a reference level is ______

level Signup and view all the answers

The ratio of the level of the modulated output of a transmitter under conditions of standard test modulation to the level of the demodulated output with no modulation applied both measured with the same bandwidth

Residual noise level Signup and view all the answers

What type of circuit reduces even order harmonics?

Push Pull Signup and view all the answers

"Pink" noise has:

equal power per octave Signup and view all the answers

Random interference to transmitted signal is called

Noise Signup and view all the answers

Quantizing noise occurs in

PCM Signup and view all the answers

_______ is the noise created by man

Industrial Signup and view all the answers

A special service that any individual may use for personal communication with others

Citizen's radio Signup and view all the answers

Crosstalk dues to incomplete suppression of sideband or to intermodulation of two or more frequency-multiplexed channels which is unintelligible is classified as

Miscellaneous Noise Signup and view all the answers

Which expression indicates a measurement using a 1-W reference

dBW Signup and view all the answers

Recovering information from a carrier is known as

detection Signup and view all the answers

________ is measured on a circuit when it is correctly terminated but does not have any traffic

White noise Signup and view all the answers

In a communication system noise is likely to affect the signal

In the channel Signup and view all the answers

If bandwidth is double, the signal power is ____

Not changed Signup and view all the answers

In telecommunications, what do we call the difference in the voltage levels between a driver and a terminator

System gain Signup and view all the answers

Which of the following can be called a troubleshooting plan?

All of the above Signup and view all the answers

Television broadcasting occurs in which range

VHF Signup and view all the answers

External noise field are measured in terms of ______

Peak values Signup and view all the answers

Collection of one or more electronic devices or circuits that converts the original source information to a form more suitable for transmission over a particular transmission medium

Transmitter Signup and view all the answers

Which of the following is not true?

Impulse noise voltage is independent of bandwidth Signup and view all the answers

The person who sent the first radio signal across the Atlantic ocean was:

Marconi Signup and view all the answers

The acoustic channel is used for which of the following?

person-to-person voice communications Signup and view all the answers

Cosmic noise is produced by

Distant stars Signup and view all the answers

Absolute temperature in Kelvin

°C + 273 Signup and view all the answers

Two tuned circuit are said to be ______ each other when the resonant frequencies can be made to vary in the same proportion by rotating a common shaft

Tracking Signup and view all the answers

Occurs when two or more signals combine in a linear device

Linear summing Signup and view all the answers

The collection of sinusoidal frequencies present in a modulated carrier is called its:

All of the above Signup and view all the answers

Space noise generally covers a wide frequency spectrum, but the strongest interference occurs

between 20 to 120 MHz Signup and view all the answers

What is the major cause of atmospheric or static noise?

Thunderstorms Signup and view all the answers

Interfering effect of noise, C message weighted, is

dBmc Signup and view all the answers

the process of converting a frequency or band of frequencies to another location in the frequency spectrum

Frequency translation Signup and view all the answers

Distortion occurs when the _____ harmonic components of a digital square wave are lost.

High frequency Signup and view all the answers

When two noise voltages, V1 and V2 are combined, the total voltage Vt is:

VT = sqrt(V1 x V1 + V2 x V2) Signup and view all the answers

The communication medium causes the signal to be

Attenuated Signup and view all the answers

Noise always affects the signal in a communication system at the ______

channel Signup and view all the answers

A voltage change that is equal to twice its original value correspond to a change of

6 dB Signup and view all the answers

Electromagnetic radiation generally associated with heat and is used in heat seeking guidance systems, photography and astronomy

Infrared Signup and view all the answers

Atmospheric noise or static is not a great problem

At frequencies above 30 MHz Signup and view all the answers

Which of the following is not an example of external noise

Resistor noise Signup and view all the answers

Signup and view all the answers

Which standard recommends crosstalk limits?

CCIT G.151 Signup and view all the answers

The noise power generated by a resistor is proportional to

a and b Signup and view all the answers

The _ the equivalent noise temperature is, the _ the quality of the receiver

Lower, Better Signup and view all the answers

Sources of impulse noise induced in communication channels

All of these Signup and view all the answers

In a communication system, noise is most likely to affect the signal

in the channel Signup and view all the answers

Electromagnetic waves produced primarily by heat are called

Infrared rays Signup and view all the answers

Form of interference caused by rain or dust storms

Precipitation static Signup and view all the answers

Absence of one of the following components in a parametric amplifier renders this circuit a low-noise amplifier

Resistance Signup and view all the answers

It is a free running oscillator with a stable frequency of oscillation that depends on a external timing capacitance, timing resistance and control voltage

Voltage Control Oscillator Signup and view all the answers

The transmission of radio waves was first done by:

Hertz Signup and view all the answers

Amplitude modulation is the process of

superimposing a low frequency on a high frequency Signup and view all the answers

One of the following type of noise becomes of great importance in high frequencies. It is the

Transit-time noise Signup and view all the answers

If bandwidth is doubled, the signal power is

not changed Signup and view all the answers

_____ sets a limit on the maximum capacity of a channel with a given noise level

Shannon - Hartley theorem Signup and view all the answers

Modulation used is to the following except

Reduced the bandwidth used Signup and view all the answers

The baseband bandwidth for a voice-grade (telephone) signal is:

Approximately 3 kHz Signup and view all the answers

When dealing with random noise calculation it must be remembered that

calculations are based on RMS Signup and view all the answers

Background noise is the same as the following EXCEPT

Impulse noise Signup and view all the answers

F1A weighting refers to _____

dBrnc Signup and view all the answers

The most common unit of noise measurement in white noise voltage testing

NPR Signup and view all the answers

Power is ____

Definite amount of energy per time period Signup and view all the answers

Signal-to-Noise ratio is calculated as:

signal power divided by noise power Signup and view all the answers

Which of the following is not a source of noise

Another communication signal Signup and view all the answers

______ is the random and unpredictable electric signals from natural causes, both internal and external to the system

Noise Signup and view all the answers

Indicate the voltage level in dB with reference to one volt. This unit is used in video or TV measurement

dBV Signup and view all the answers

_____ noise is produced by nonlinear amplification and includes harmonic and intermodulation distortion

Correlated Noise Signup and view all the answers

The resolution bandwidth of a spectrum analyzer depends upon

None of these Signup and view all the answers

Why does a 5 -kHz square wave require a greater bandwidth than a 2-kHz sinewave

The square wave has infinite number of harmonics, whereas the sinewave has only one Signup and view all the answers

Measuring physical conditions at some remote location and transmitting this data for analysis is the process of

Telemetry Signup and view all the answers

Which standard is utilized in intermodulation noise rates on PCM audio channels?

CCIT Rec. G.172 Signup and view all the answers

Signup and view all the answers

Noise and dB

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Questions and Answers

Which of the following crystal is commonly used in microphones

The Theory of radio waves was orginated by:

Which of the steps is not included in the process of reception?

Man-made noise is cause by

Standard design reference for environmental noise temperature

Standardized as the amplitude of the carrier voltage modulated 30% by 400Hz signal which when applied to the receiver input through a standard antenna will develop an output of 0.5W in a resistive load

_______ is measured on a circuit when it is correctly terminated but does not have any traffic

Distortion is caused by

Which of broad classifications of noise are most difficult to treat?

The most common unit of noise measurement in white noise voltage testing

The difference between signal strength at a given point and a reference level is ______

The ratio of the level of the modulated output of a transmitter under conditions of standard test modulation to the level of the demodulated output with no modulation applied both measured with the same bandwidth

What type of circuit reduces even order harmonics?

"Pink" noise has:

Random interference to transmitted signal is called

Quantizing noise occurs in

_______ is the noise created by man

A special service that any individual may use for personal communication with others

Crosstalk dues to incomplete suppression of sideband or to intermodulation of two or more frequency-multiplexed channels which is unintelligible is classified as

Which expression indicates a measurement using a 1-W reference

Recovering information from a carrier is known as

________ is measured on a circuit when it is correctly terminated but does not have any traffic

In a communication system noise is likely to affect the signal

If bandwidth is double, the signal power is ____

In telecommunications, what do we call the difference in the voltage levels between a driver and a terminator

Which of the following can be called a troubleshooting plan?

Television broadcasting occurs in which range

External noise field are measured in terms of ______

Collection of one or more electronic devices or circuits that converts the original source information to a form more suitable for transmission over a particular transmission medium

Which of the following is not true?

The person who sent the first radio signal across the Atlantic ocean was:

The acoustic channel is used for which of the following?

Cosmic noise is produced by

Absolute temperature in Kelvin

Two tuned circuit are said to be ______ each other when the resonant frequencies can be made to vary in the same proportion by rotating a common shaft

Occurs when two or more signals combine in a linear device

The collection of sinusoidal frequencies present in a modulated carrier is called its:

Space noise generally covers a wide frequency spectrum, but the strongest interference occurs

What is the major cause of atmospheric or static noise?

Interfering effect of noise, C message weighted, is

the process of converting a frequency or band of frequencies to another location in the frequency spectrum

Distortion occurs when the _____ harmonic components of a digital square wave are lost.

When two noise voltages, V1 and V2 are combined, the total voltage Vt is:

The communication medium causes the signal to be

Noise always affects the signal in a communication system at the ______

A voltage change that is equal to twice its original value correspond to a change of

Electromagnetic radiation generally associated with heat and is used in heat seeking guidance systems, photography and astronomy

Atmospheric noise or static is not a great problem

Which of the following is not an example of external noise

Which standard recommends crosstalk limits?

The noise power generated by a resistor is proportional to

The _____ the equivalent noise temperature is, the _____ the quality of the receiver

Sources of impulse noise induced in communication channels

In a communication system, noise is most likely to affect the signal

Electromagnetic waves produced primarily by heat are called

Form of interference caused by rain or dust storms

Absence of one of the following components in a parametric amplifier renders this circuit a low-noise amplifier

It is a free running oscillator with a stable frequency of oscillation that depends on a external timing capacitance, timing resistance and control voltage

The transmission of radio waves was first done by:

Amplitude modulation is the process of

One of the following type of noise becomes of great importance in high frequencies. It is the

If bandwidth is doubled, the signal power is

_____ sets a limit on the maximum capacity of a channel with a given noise level

Modulation used is to the following except

The baseband bandwidth for a voice-grade (telephone) signal is:

When dealing with random noise calculation it must be remembered that

Background noise is the same as the following EXCEPT

F1A weighting refers to _____

The most common unit of noise measurement in white noise voltage testing

Power is ____

Signal-to-Noise ratio is calculated as:

Which of the following is not a source of noise

______ is the random and unpredictable electric signals from natural causes, both internal and external to the system

Indicate the voltage level in dB with reference to one volt. This unit is used in video or TV measurement

_____ noise is produced by nonlinear amplification and includes harmonic and intermodulation distortion

The resolution bandwidth of a spectrum analyzer depends upon

The _ the equivalent noise temperature is, the _ the quality of the receiver