What is the reason why companding is employed in PCM systems? A. To overcome impulse noise in PCM receivers B. To allow amplitude limiting in the receivers C. To solve quantizing noise problem D. To protect small signals in PCM from quantizing distortion

What is the reason why companding is employed in PCM systems?
A. To overcome impulse noise in PCM receivers
B. To allow amplitude limiting in the receivers
C. To solve quantizing noise problem
D. To protect small signals in PCM from quantizing distortion
by

1 Answer

Answer :

D. To protect small signals in PCM from quantizing distortion
by

Related questions

Noise consisting of irregular pulses of short duration and relatively high amplitude, A. Quantizing noise B. Tone interference C. Impulse noise D. Cross talk

Description : Noise consisting of irregular pulses of short duration and relatively high amplitude, A. Quantizing noise B. Tone interference C. Impulse noise D. Cross talk

Last Answer : C. Impulse noise

Noise consisting of irregular pulses of short duration and relatively high amplitude, A. Quantizing noise B. Tone interference C. Impulse noise D. Cross talk

Description : Noise consisting of irregular pulses of short duration and relatively high amplitude, A. Quantizing noise B. Tone interference C. Impulse noise D. Cross talk

Last Answer : A. Quantizing noise

ECE Board Exam March 1996 What is the purpose of the receiver’s squelch circuit? A. To overcome fluctuations in the level the RF signal arriving at the receiver antenna B. To prevent fluctuations in the AGC bias level C. To reduce the receiver’s sensitivity to all incoming signals D. To prevent amplified noise from reaching the loudspeaker during the absence of an incoming signal

Description : ECE Board Exam March 1996 What is the purpose of the receiver's squelch circuit? A. To overcome fluctuations in the level the RF signal arriving at the receiver antenna B. To prevent ... signals D. To prevent amplified noise from reaching the loudspeaker during the absence of an incoming signal

Last Answer : D. To prevent amplified noise from reaching the loudspeaker during the absence of an incoming signal

Quantizing noise occurs in A. PCM B. PLM C. PDM D. PAM

Description : Quantizing noise occurs in A. PCM B. PLM C. PDM D. PAM

Last Answer : A. PCM

Crosstalk due to incomplete suppression of sidebands or to intermodulation of two or more frequency-multiplexed channels which is unintelligible is classified as A. Impulse noise B. Thermal noise C. Quantizing noise D. Miscellaneous noise

Description : Crosstalk due to incomplete suppression of sidebands or to intermodulation of two or more frequency-multiplexed channels which is unintelligible is classified as A. Impulse noise B. Thermal noise C. Quantizing noise D. Miscellaneous noise

Last Answer : D. Miscellaneous noise

Noise occurring in the presence of signal resulting from a mismatch between the exact value of an analog signal and the closet available quantizing step in a digital coder. A. Quantizing noise B. Thermal noise C. Impulse noise D. Crosstalk

Description : Noise occurring in the presence of signal resulting from a mismatch between the exact value of an analog signal and the closet available quantizing step in a digital coder. A. Quantizing noise B. Thermal noise C. Impulse noise D. Crosstalk

Last Answer : A. Quantizing noise

Steps to follow to produce PCM signal. A. Quantizing, sampling, and coding B. Sampling, quantizing, and coding C. Sampling, coding and quantizing D. Coding, quantizing and coding

Description : Steps to follow to produce PCM signal. A. Quantizing, sampling, and coding B. Sampling, quantizing, and coding C. Sampling, coding and quantizing D. Coding, quantizing and coding

Last Answer : B. Sampling, quantizing, and coding

The process of assigning PCM codes to absolute magnitudes A. Overloading B. All of these C. Quantizing D. Multiplexing

Description : The process of assigning PCM codes to absolute magnitudes A. Overloading B. All of these C. Quantizing D. Multiplexing

Last Answer : C. Quantizing

Which of the following term best described the overload distortion? A. Peak limiting B. Quantization noise C. Granular noise D. Slope distortion

Description : Which of the following term best described the overload distortion? A. Peak limiting B. Quantization noise C. Granular noise D. Slope distortion

Last Answer : A. Peak limiting

_________ is the random and unpredictable electric signals from natural causes, both internal and external to the system. A. Interference B. Attenuation C. Distortion D. Noise

Description : _________ is the random and unpredictable electric signals from natural causes, both internal and external to the system. A. Interference B. Attenuation C. Distortion D. Noise

Last Answer : D. Noise

What is the mixing process? A. Distortion caused by auroral propagation B. The combination of two signals to produce sum and difference frequencies. C. The elimination of noise in wideband receiver by phase differentiation D. The elimination of noise in a wideband receiver by phase comparison

Description : What is the mixing process? A. Distortion caused by auroral propagation B. The combination of two signals to produce sum and difference frequencies. C. The elimination of noise in wideband receiver by phase differentiation D. The elimination of noise in a wideband receiver by phase comparison

Last Answer : B. The combination of two signals to produce sum and difference frequencies.

________ is the method of encoding audio signals used in US standard 1544 kbit/s 24 channel PCM systems. A. Shannon’s law B. A-law C. Newton’s law D. Mu-law

Description : ________ is the method of encoding audio signals used in US standard 1544 kbit/s 24 channel PCM systems. A. Shannon’s law B. A-law C. Newton’s law D. Mu-law

Last Answer : D. Mu-law

_______ is more prevalent in analog signals that have steep slopes or whose amplitudes vary rapidly. A. Peak limiting B. Quantization noise C. Granular noise D. Slope overload

Description : _______ is more prevalent in analog signals that have steep slopes or whose amplitudes vary rapidly. A. Peak limiting B. Quantization noise C. Granular noise D. Slope overload

Last Answer : D. Slope overload

Sources of impulse noise induced in communication channels. A. Erroneous digital coding bit caused by an error on a transmission facility B. Transients due to relay operation C. Crosstalk from dc signaling systems D. All of these

Description : Sources of impulse noise induced in communication channels. A. Erroneous digital coding bit caused by an error on a transmission facility B. Transients due to relay operation C. Crosstalk from dc signaling systems D. All of these

Last Answer : D. All of these

Noise that occurs via capacitive or inductive coupling in a cable. A. Crosstalk B. Quantizing noise C. Reference noise D. Tone interference

Description : Noise that occurs via capacitive or inductive coupling in a cable. A. Crosstalk B. Quantizing noise C. Reference noise D. Tone interference

Last Answer : A. Crosstalk

The difference between the original and reconstructed signal gives rise to A. S factor B. Quantizing noise C. S/N D. Fade margin

Description : The difference between the original and reconstructed signal gives rise to A. S factor B. Quantizing noise C. S/N D. Fade margin

Last Answer : B. Quantizing noise

Which does not effect noise in a channel? A. None of these B. Bandwidth C. Temperature D. Quantizing level

Description : Which does not effect noise in a channel? A. None of these B. Bandwidth C. Temperature D. Quantizing level

Last Answer : D. Quantizing level

One of the following is not a useful quantity for comparing the noise performance receivers. A. Input noise voltage B. Equivalent noise resistance C. Noise temperature D. Noise figure.

Description : One of the following is not a useful quantity for comparing the noise performance receivers. A. Input noise voltage B. Equivalent noise resistance C. Noise temperature D. Noise figure.

Last Answer : A. Input noise voltage

ECE Board Exam March 1996 A receiver connected to an antenna whose resistance is 50 ohms has an equivalent noise resistance of 30 ohms. What is the receiver’s noise temperature? A. 754 K B. 464 K C. 174 K D. 293 K

Description : ECE Board Exam March 1996 A receiver connected to an antenna whose resistance is 50 ohms has an equivalent noise resistance of 30 ohms. What is the receiver’s noise temperature? A. 754 K B. 464 K C. 174 K D. 293 K

Last Answer : C. 174 K

What distortion is not caused by transmission line characteristics? A. Phase distortion B. Pulse shape distortion C. Spacing bias distortion D. Amplitude distortion

Description : What distortion is not caused by transmission line characteristics? A. Phase distortion B. Pulse shape distortion C. Spacing bias distortion D. Amplitude distortion

Last Answer : C. Spacing bias distortion

This is referred to a product of simultaneous frequency and amplitude modulation or a carrier frequency variation which produces unwanted distortion. A. Absorption modulation B. Simultaneous modulation C. Dynamic instability D. Series modulation

Description : This is referred to a product of simultaneous frequency and amplitude modulation or a carrier frequency variation which produces unwanted distortion. A. Absorption modulation B. Simultaneous modulation C. Dynamic instability D. Series modulation

Last Answer : C. Dynamic instability

What does the noise weighting curve shows? A. Noise signals measured with a 144 handset B. Power levels of noise found in carrier systems C. The interfering effect of other frequencies in a voice channel compared with a reference frequency of one kilohertz D. Interfering effects of signals compared with a 3-kHz tone

Description : What does the noise weighting curve shows? A. Noise signals measured with a 144 handset B. Power levels of noise found in carrier systems C. The interfering effect of other frequencies in a voice ... a reference frequency of one kilohertz D. Interfering effects of signals compared with a 3-kHz tone

Last Answer : C. The interfering effect of other frequencies in a voice channel compared with a reference frequency of one kilohertz

Which standard is utilized in intermodulation noise rates on PCM audio channels? A. CCIT Rec. G.151 B. CCIT Rec. G.172 C. CCIT Rec. G.190 D. CCIT Rec. G.190

Description : Which standard is utilized in intermodulation noise rates on PCM audio channels? A. CCIT Rec. G.151 B. CCIT Rec. G.172 C. CCIT Rec. G.190 D. CCIT Rec. G.190

Last Answer : B. CCIT Rec. G.172

Which causes a quantization noise in PCM system? A. Serial transmission errors B. The approximation of the quantized signal C. The synchronization between encoder and decoder D. Binary coding techniques

Description : Which causes a quantization noise in PCM system? A. Serial transmission errors B. The approximation of the quantized signal C. The synchronization between encoder and decoder D. Binary coding techniques

Last Answer : B. The approximation of the quantized signal

Which causes a quantization noise in PCM system? A. Serial transmission errors B. The approximation of the quantized signal C. The synchronization between encoder and decoder D. Binary coding techniques

Description : Which causes a quantization noise in PCM system? A. Serial transmission errors B. The approximation of the quantized signal C. The synchronization between encoder and decoder D. Binary coding techniques

Last Answer : The approximation of the quantized signal

What is the quantization signal-to-noise ratio if an 8-bit PCM code is used? A. 40 dB B. 50 dB C. 60 dB D. 65 dB

Description : What is the quantization signal-to-noise ratio if an 8-bit PCM code is used? A. 40 dB B. 50 dB C. 60 dB D. 65 dB

Last Answer : B. 50 dB

The main problem with such a heat treatment of stainless steel pipe spools and the reason why it is not regularly employed is: a) Controlling the rate of the temperature rise b) Controlling the cooling c) The length of the soak period d) High risk of distortion

Description : The main problem with such a heat treatment of stainless steel pipe spools and the reason why it is not regularly employed is: a) Controlling the rate of the temperature rise b) Controlling the cooling c) The length of the soak period d) High risk of distortion

Last Answer : d) High risk of distortion

The random and unpredictable electric signal from natural causes, both internal and external to the system is know as ________. A. Distortion B. Noise C. Attenuation D. Interference

Description : The random and unpredictable electric signal from natural causes, both internal and external to the system is know as ________. A. Distortion B. Noise C. Attenuation D. Interference

Last Answer : B. Noise

ECE Board Exam March 1996 Which of the following pulse modulation systems is analog? A. Delta B. Differential PCM C. PWM D. PCM

Description : ECE Board Exam March 1996 Which of the following pulse modulation systems is analog? A. Delta B. Differential PCM C. PWM D. PCM

Last Answer : C. PWM

Which of the following types of noise becomes of great importance at frequencies? A. Shot noise B. Random noise C. Impulse noise D. Transit-time noise

Description : Which of the following types of noise becomes of great importance at frequencies? A. Shot noise B. Random noise C. Impulse noise D. Transit-time noise

Last Answer : D. Transit-time noise

Indicate the false statement. A. HF mixer are generally noisier than HF amplifiers. B. Impulse noise voltage is dependent on bandwidth C. Thermal noise is independent of the frequency at which is measured. D. Industrial noise is usually of the impulse type.

Description : Indicate the false statement. A. HF mixer are generally noisier than HF amplifiers. B. Impulse noise voltage is dependent on bandwidth C. Thermal noise is independent of the frequency at which is measured. D. Industrial noise is usually of the impulse type.

Last Answer : B. Impulse noise voltage is dependent on bandwidth

Indicate the false statement. A. Industrial noise is usually of the impulse type B. Static is caused by lightning discharges in thunderstorms and other natural electric disturbances occurring in the atmosphere C. Distant stars are another source of man-made noise D. Flourescent lights are another source of man-made noise

Description : Indicate the false statement. A. Industrial noise is usually of the impulse type B. Static is caused by lightning discharges in thunderstorms and other natural electric disturbances occurring in the ... another source of man-made noise D. Flourescent lights are another source of man-made noise

Last Answer : C. Distant stars are another source of man-made noise

Form of interference caused by rain or dust storms. A. Precipitation static B. Shot-noise C. Galactic noise D. Impulse noise

Description : Form of interference caused by rain or dust storms. A. Precipitation static B. Shot-noise C. Galactic noise D. Impulse noise

Last Answer : A. Precipitation static

_________ is measured on a circuit when it is correctly terminated but does not have any traffic. A. White noise B. Galactic noise C. Impulse noise D. Atmospheric noise

Description : _________ is measured on a circuit when it is correctly terminated but does not have any traffic. A. White noise B. Galactic noise C. Impulse noise D. Atmospheric noise

Last Answer : A. White noise

What do you call the random noise seen on radar display screen? A. Impulse noise B. Atmospheric noise C. Grass D. Johnson noise

Description : What do you call the random noise seen on radar display screen? A. Impulse noise B. Atmospheric noise C. Grass D. Johnson noise

Last Answer : C. Grass

What noise is a transient short-duration disturbance distributed essentially uniformly over the useful passband of a transmission system? A. Flicker noise B. Transit-time noise C. Shot noise D. Impulse noise

Description : What noise is a transient short-duration disturbance distributed essentially uniformly over the useful passband of a transmission system? A. Flicker noise B. Transit-time noise C. Shot noise D. Impulse noise

Last Answer : D. Impulse noise

ECE Board Exam March 1996 The expander in a companding device provides ___________. A. greater amplification for low signal levelsB. less amplification for low signal levels C. greater amplification for high signal levels D. lesser pressure for transmission

Description : ECE Board Exam March 1996 The expander in a companding device provides ___________. A. greater amplification for low signal levels B. less amplification for low signal levels C. greater amplification for high signal levels D. lesser pressure for transmission

Last Answer : B. less amplification for low signal levels

What are the merits of companding?

Description : What are the merits of companding?

Last Answer : *The compression process reduces the dynamic range of the signal before it is transmitted. *Companding preserves the signal to noise ratio of the original signal and avoids non linear distortion of the ... is large. *It also reduces buzz,bias and low level audio tones caused by mild interference.

The most common method used for sampling voice signals in PCM systems.

Description : The most common method used for sampling voice signals in PCM systems.

Last Answer : flat top sampling

A method of expressing the amplitude of complex non-periodic signals such as speech. A. Frequency B. Wavelength C. Volume D. Pitch

Description : A method of expressing the amplitude of complex non-periodic signals such as speech. A. Frequency B. Wavelength C. Volume D. Pitch

Last Answer : C. Volume

Modulation means A. Varying of information B. Utilization of a single transmission channel to carry multiple signals C. Varying of some parameters of a carrier such as its amplitude to transmit information D. Transmit pulses in DC form on a copper wire

Description : Modulation means A. Varying of information B. Utilization of a single transmission channel to carry multiple signals C. Varying of some parameters of a carrier such as its amplitude to transmit information D. Transmit pulses in DC form on a copper wire

Last Answer : C. Varying of some parameters of a carrier such as its amplitude to transmit information

Companding helps in reducing __________ with respect to signal: (A) Interference (B) Signal overloading (C) Non linearity (D) Quantization noise

Description : Companding helps in reducing __________ with respect to signal: (A) Interference (B) Signal overloading (C) Non linearity (D) Quantization noise

Last Answer : (D) Quantization noise

What is the effect in over modulated amplitude modulated radio broadcasting transmission? A. Interference to adjacent channel B. Higher fidelity C. Increase noise D. Higher audio signal

Description : What is the effect in over modulated amplitude modulated radio broadcasting transmission? A. Interference to adjacent channel B. Higher fidelity C. Increase noise D. Higher audio signal

Last Answer : A. Interference to adjacent channel

What is the greatest limiting factor in a receiver’s detectable range

Description : What is the greatest limiting factor in a receiver’s detectable range

Last Answer : Noise.

Stacking antenna elements A. increases sensitivity to weak signals B. will suppress odd harmonics C. decrease signal to noise ratio D. increases selectivity

Description : Stacking antenna elements A. increases sensitivity to weak signals B. will suppress odd harmonics C. decrease signal to noise ratio D. increases selectivity

Last Answer : A. increases sensitivity to weak signals

An advantage of optic fiber rejecting an induced noise signals from magnetic field or solar storms flux. A. Electric hazard B. Cross talk C. Immunity to noise D. Shielding

Description : An advantage of optic fiber rejecting an induced noise signals from magnetic field or solar storms flux. A. Electric hazard B. Cross talk C. Immunity to noise D. Shielding

Last Answer : C. Immunity to noise

In order to reduce quantizing noise, one must

Last Answer : In order to reduce quantizing noise, one must Increase the number of standard amplitudes.

Explain the basic architecture of digital switching systems. Explain in detail companding.

Description : Explain the basic architecture of digital switching systems. Explain in detail companding.

Last Answer : A simple N X N time division space switch is shown in Fig. The switch can be represented in an equivalence form as a two-stage network with N X 1 and 1 X N switching matrices for the first and ... = Parameter used to define the amount of compression  Vout = Compressed output voltage. 

Which of the following systems is not used in radio detection and ranging? A. Frequency shift B. Frequency modulation C. Pulse radar D. Amplitude modulation

Description : Which of the following systems is not used in radio detection and ranging? A. Frequency shift B. Frequency modulation C. Pulse radar D. Amplitude modulation

Last Answer : D. Amplitude modulation

In damped vibrations, the amplitude of the resulting vibration gradually reduces. This is due to the reason that an amount of energy is always dissipated to overcome the ________ * 1 point (A) Frictional resistance (B) Work done(C) Fluid pressure (D) Air pressure

Description : In damped vibrations, the amplitude of the resulting vibration gradually reduces. This is due to the reason that an amount of energy is always dissipated to overcome the ________ * 1 point (A) Frictional resistance (B) Work done(C) Fluid pressure (D) Air pressure

Last Answer : (A) Frictional resistance