Noise.docx

NoiseQuestText Choice1 Choice2 Choice3 Choice4 Subj

_____ is a short-term variations of the significant instants of a digital signal from their ideal position in time.

Jitter Distortion Latch Amplified Noise

_____ is an electronic noise produced by thermal agitation of electron in conductor and semiconductor.

Thermal noise Internal noise External noise Flicker Noise

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

White noise Galactic noise Impulse noise Atmospheric noise Noise

_____ is the amount of output signal voltage produce with 1 microbar (74 dB SPL) 1000Hz signal in microphones.

Sensitivity Directivity Distortion Dispersion Noise

_____ is the random and unpredictable electric signals from natural causes both internal and external to the system.

Noise Interference Attenuation Distortion Noise

_____ is the sound of the talker's voice in his own receiver. Sidetone Dualtone Echotone Anti-tone NoiseA -30 dBW is equivalent to: 0 dBm 0 dB 0 dBf 0 dBW NoiseA combiner has two inputs +30 dBm and +30 dBm, what is the resultant output?

+ 33 dBm + 30 dBm + 60 dBm + 36 dBm Noise

A long-term variations in a waveform. Jitter Attenuation Defect Orderwire NoiseA low ratio of the ac to the dc load impedance of a diode detector results in

Negative-peak clipping Poor AF response Diagonal operation Poor AGC operation Noise

A noise in radio system was measured to read 58 dBm, what does this represent in dBm?

-32 32 148 90 Noise

Reference noise temperature. 290 K 17* F 30*C 25*C NoiseReference temperature used in noise analysis. 290 K 75 K 250 K 300 K NoiseA unit of noisiness related to the perceived noise level Noy Sone DB Phone NoiseDisruptions in a signal channel caused by power leaking from an adjacent channel. Common causes are poor frequency planning, insufficient filtering, use of incorrect power, or anomalies in propagation.

Adjacent Channel Interference Cochannel Interference Propagation noise None of the above Noise

The following measurements were taken in a circuit: Noise 25 dB 91 dB 33 dB 1.1 dB Noise


with tone in 58 dbmC C-notch noise in 33 dbmC. What is the signal-to-noise ratio(S/N) of the circuit?In the frequency domain, overmodulation result inner frequencies besides the simple sum and difference ones of regular AM. These new frequencies are outside the regular AM spectrum and are called:

Splatter Phase distortion Noise Amplitude distortion Noise

Man-made noise is usually from ________. Transmission over power lines and by ground wave

Sky-wave Space-wave Troposphere Noise

Most internal noise comes from Thermal agitation Shot noise Transit-time noise Skin effect NoiseThe highest noise factor will be produced by a frequency of ____.

10000 Hz 500 Hz 1000 Hz 200 Hz Noise

The standard deviation of the variation in the transmission loss of a circuit should not exceed

1 dB 2 db 3 dB 0.5 dB Noise

A signal is AMplified 100 times in power. The dB gain is: 20dB 19dB 15dB 25dB NoiseA ten times power change in a transmission system is equal

10 dB 100 dB 100 dB 1 dB Noise

At 17 degree C, the noise voltage generated by 5-kilohm resistor operating over a bandwidth of 20 kHz is

1.3 microvolts 1.3 nV 1.3 pV 1.3 mV Noise

Atmospheric noise becomes less severe at frequencies Above 30 MHz Below 30 MHz Above 3000 kHz Below 3000 kHz NoiseAtmospheric noise is known as ______ noise. Static Cosmic Solar Lunar NoiseBackground noise is the same as the following except Impulse noise White noise Thermal noise Gaussian noise NoiseConsidered as the main source of internal noise. Thermal agitation Device imperfection Temperature change Flicker NoisedBa is decibels adjusted and has a reference of 10^-11.5 W 10^-15 W 10^-12 W 10^-11 W NoiseExpress 0.05 volt in dBV. -26 dBV +30 dBV +26 dBV -30 dBV NoiseExtra-terrestrial noise is observable at frequencies from 8 to 1.43 GHz 0 to 20 kHz Above 2 GHz 5 to 8 GHz NoiseExtra-terrestrial noise is observable at frequencies from ______.

1 to 1.43 GHz 0 to 20 kHz Above 2 GHz 5 to 8 GHz Noise

Extre-terrestrial noise is observable at frequencies from 8 to 1.43 GHz 5 to 8 GHz Above 2 GHz 0 to 20 kHz Noise


Find the noise temperature of a receiver with a noise figure of 2 dB

169.6 K 144 K 100.2 K 128.8 K Noise

Generally referred to as the primary cause of atmospheric noise.

Lightning Rain effect El niño phenomenon Thunderstorm Noise

Given three amplifiers in cascade each with a noise filter of 3 dB and power gain of 10 dB. What is the noise figure?

3dB 7dB 10dB 6dB Noise

If the voltage change is equal to twice its original value, what is its corresponding change in dB?


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

In the channel At the transmitter In the information source

At the destination Noise

In a receiver with noise derived squelch, the presence of an audio causes the audio amplifier to be

Enabled Disabled Nothing will happen None of the above Noise

In order to reduce quantizing noise, one must Increase the number of standard amplification

Send pulses whose sides are more nearly vertical

Use an RF amplifier Increase the number of samples per second

Noise

Indicate the false statement. From the transmitter the signal deterioration because of noise is usually

Predictable in character Unwanted energy Present in the transmitter

Due to any cause Noise

Indicate the false statement. In order to combat noise The channel bandwidth maybe increased

Redundancy may be used

The transmitted power may be increased

The signaling rate may be reduced

Noise

Indicate the noise whose source is in a category different from that of the other three

Atmospheric noise Solar noise Galactic noise Cosmic noise Noise

Industrial noise frequency is between 15 to 160 MHz 0 to 10 MHz 20 GHz 200 to 3000 MHz NoiseIt is a high gain,low noise level, audio frequency amplifier and a square law calibrated vacuum tube voltmeter used to amplify and measure the output of a crystal and display the information

Standing wave indicator Power level indicator Voltmeter Pilot indicator Noise

Known as one-tenth of a neper. dNp dB dBm dBp NoiseNoise always affect the signal in a communications systems at the

Channel Transmitter Information source Destination Noise


Noise at the input to a receiver can be as high as several Microvolts Millivolts Volts Kilovolts NoiseNoise caused by the thermal agitation of electrons in resistance.

All of the above Thermal noise Johnson's noise White noise Noise

Noise caused by thermal agitation of electrons in resistance.

All of these Thermal noise Johnson's noise White noise Noise

Noise corrected to 0 TLP DBrnCO DBWO DBrnC DBmO NoiseNoise from random acoustic or electric noise that has equal energy per cycle over a specified total frequency band.

All of the above Thermal noise White noise Gaussian noise Noise

Noise from random acoustic or electric noise that has equal per cycle over a specified total frequency band.

All of the above Thermal noise White noise Gaussian noise Noise

Noise is primarily a High frequency spikes Low frequency variation Random level shifts Random frequency variation

Noise

One of the following is not a useful quantity for comparing the noise performance of receivers

Input noise voltage Equivalent noise resistance

Noise temperature Noise figure Noise

One of the following types of noise becomes of great importance at high frequencies. It is the

Transit-time noise Shot noise Random noise Impulse noise Noise

Quantization noise is caused by The approximation of the quantized signal

The synchronization between encoder and decoder

Serial transmission errors

Binary coding techniques

Noise

Quantizing noise occurs Pulse-code modulation Pulse-width modulation Time-division multiplex Frequency division multiplex

Noise

Quantizing noise occurs in PCM PLM PDM PAM NoiseSpace noise generally covers a wide frequency spectrum, but the strongest interference occurs

Between 20 to 120 MHz Below 8 MHz and 1.43 GHz

Between 8 MHz and 1.43 GHz

Above 1.5 GHz Noise

The value of resistor creating thermal noise is doubled. The noise power generated is therefore

Unchanged Halved Quadrupled Doubled Noise

The equivalent noise temperature of the amplifier is 25 K, 1.086 1.86 0.1086 10.86 Noise


what is the noise figure?The modulation system inherently more resistant to noise. Frequency modulation Phase shift keying Pulse-position

modulationSingle sideband suppressed carrier

Noise

The modulation system inherently most noise resistant is Pulse code modulation SS suppressed carrier Frequency modulation Pulse position modulation

Noise

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

NPR DBm DBW DBk Noise

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

NPR DBm DBW DBrn Noise

The noise factor of an ideal AMplifier expressed in dB is ___.

0 0.1 1 10 Noise

The noise generated by TDM carrier system is _______ that generated by analog carrier systems.

Much less than About the same A little less than Greater than Noise

The noise generated by TDM carrier systems is _____ that generated by analog carrier systems.

Much less than About the same as A little less than Greater than Noise

The noise voltage accross the 300 ohm input resistance to a TV set with 6 MHz bandwidth and a temperature of 30°C is

3.8 uV 2.3 uV 5.5 uV 6.4 uV Noise

The pre-emphasis circuit introduced in the FM transmitter provides extra noise immunity by

Amplifying the high audio frequency Boosting the low frequency

Preamplifying the whole audio band

Converting the phase modulation to FM

Noise

What does the noise weighting curve shows? The interfering effect of other frequencies in a voice channel compared with a reference freq of 1 kHz

Interfering effects of signals compared with a 3-kHz tone

Noise signals measured with a 144 handset

Power levels of noise found in carrier systems

Noise

Where is the noise generated that primarily determines the signal-to- noise ratio in a VHF (150 MHz) marine band receiver?

In the receiver front end In the receiver rear end In the ionosphere In the atmosphere Noise

Which causes quantization noise in PCM system? The approximation of the quantized noise

Serial transmission error The synchronization between encoder and

Binary coding techniques

Noise


decoderWhich circuit contributes most to the noise in a receiver? Mixer IF amplifier Demodulator AF amplifier NoiseThe receiver circuit that get rids of FM of noise is the Limiter Demodulator Modulator Low-pass filter NoiseThe receiver circuits that rids FM of noise is the Limiter Modulator Demodulator Low pass filter NoiseThe reference noise temperature. 290 K 70°F 30°C 25°C NoiseThe signal in a channel is measured to be 23 dB while noise in the same channel is measured to be 9 dB. the signal ratio therefore is


The signal received by an amplifier was measured to be 900 mV while the noise appearing in the same input terminals of the amplifier was measured to be 250 mV what is the S/N in dB?

11.13 0.55 3 7.13 Noise

The signal to noise ratio that is required for a satisfactory television reception?


The system with lowest noise figure in the microwave region is the

MOSFET Dual-Gate MOSFET JFET CMOSFET Noise

Two resistors, 20 kilohms and 50 kilohms are at ambient temperature. Calculate for a bandwidth equal to 100 kHz, the therla noise voltage for the two resistors connected in parallel.

4.78 uV 47.8 uV 4278 uV 0.4782 uV Noise

What is a non-continuous noise of irregular pulses or spikes of short duration with high amplitudes?

Jitter Wander Hits Singing Noise

What is the dB loss of the circuit if the power ratio of output to input is 0.01 ?

20 -20 40 -40 Noise

What is the equivalent output of a circuit in dBm if it has an output of 10 watts?

40 dBm 20 dBm 30 dBm 10 dBm Noise

What is the major cause of atmospheric noise or static noise?

Thunderstorm Meteor showers Airplanes Sunspots Noise


What is the major factor that makes coaxial cable less susceptible to noise than twisted pair cable?

Outer conductor Diameter of cable Inner conductor Insulating material Noise

What is the minimum bandwidth requires to transmit a 56 kbits/s binary signal with no noise ?

28 KHz 14 KHz 56 KHz 112 KHz Noise

What is the reference frequency of CCITT psophometric noise measurement?

800 Hz 1500 Hz 3400 Hz 1000 Hz Noise

What is the reference noise temperature? 290 K 30°C 70°F 25°C NoiseWhat is the reliable measurement for comparing amplifier noise characteristics?

Noise factor Thermal agitation noise Noise margin Signal-to-noise Noise

What is the signal-to-noise ratio for satisfactory telephone services?


What is the signal-to-noise ratio if the signal voltage is +50 volts and the noise voltage is 1.0 volt?

2500 2499.5 2500.5 2500.2 Noise

What particular circuit that rids FM of noise? Limiter HPF LPF Phase shifter NoiseWhat signal-to noise ration is required for satisfactory telephone service?


What signal-to-noise ratio is required for satisfactory telephone services?


What theorem sets a limit on the maximum capacity of a channel with a given noise level?

Shannon-Hartley theorem Nyquist theorem Hartley theorem Shannon theorem Noise

When dealing with random noise calculations it must be remembered that

Calculations are based on RMS values

All calculations are based on peak to peak values

Calculations are based on peak values

Calculations are based on average values

Noise

When the power ratio of input to output is 1/100 the loss of the circuit in dB is

-20 -10 200 3 Noise

Which lowest noise figure represents the lowest noise? 1.6 dB 2.1 dB 2.7 dB 3.4 dB NoiseWhich medium is the least susceptible to noise Fiber-optic cable Twin lead Twisted pair Coax NoiseWhich noise figure represents the lowest noise? 1.6 dB 2.1 dB 2.7 dB 3.4 dB NoiseWhich noise is produced by lighting discharges in Atmospheric noise White noise Extraterrestial noise Industrial noise Noise


thunderstorms?Which of the following is most affected by noise? ASK PSK FSK QAM NoiseWhich of the following is not a source of noise? Another commmunication signal Atmospheric effect Manufactured electrical

systemThermal agitation in electronic components

Noise

Which of the following is the most reliable measurement for comparing AMplifier noise characteristics ?

Shot noise Noise factor Signal-to-noise ratio Thermal agitation noise Noise

Which of the following low noise transistors is commonly used at microwave frequencies?

MESFET GASFET MOSFET JFET Noise

Which of the following reduces the quantization noise in a PCM system?

Increase the number of quantizing levels in the system

Increase the pulse width Using limiters at the receiver

Decrease the number of quantizing levels in the system

Noise

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

CCITT Rec. G.172 CCITT Rec. G.151 CCITT Rec. G.190 CCITT Rec. G.182 Noise

Which stands for dB relative level? DBr DBrn DBa DBx NoiseWhich two broad classifications of noise are the most difficult to treat ?

Externally generated in the receiver Noise generated in the receiver

Noise generated in the transmitter

Internally generated noise

Noise

You are measuring a voice channel at a -4 dB test point level, the meter reads -73 dBm (pure test tone) convert the reading into dBrnCO.

22 12 18 16 Noise

You are measuring noise in a voice channel at 7 dB test point level. The meter reads -56 dBm (F1A weighted). What is the reading in dBrnC?

34 20 25 32 Noise

You are measuring noise in a voice channel at a -4 dB test point level the meter reads -73 dBm convert the reading into dBrnCO.

21 12 16 18 Noise

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Noise.docx