Question 1

In the ________ scheme,a binary 0 is represented by no line signal and a binary 1 is represented by a positive or negative pulse.The binary 1 pulses must alternate in polarity.

Accepted Answer

The answer of In the ________ scheme,a binary 0 is...

Question 2

There is a transition at the middle of each bit period in the ________ biphase coding technique.The midbit transition serves as a clocking mechanism and also as data.A low-to-high transition represents a 1,and a high-to-low transition represents a 0.

Accepted Answer

The answer of There is a transition at the middle...

Question 3

The device used for converting analog data into digital form for transmission,and subsequently recovering the original analog data from the digital,is a ________.
A)modem
B)ASK
C)PAM
D)codec

Accepted Answer

A codec (coder-decoder) is the device used for converting analog data into digital form for transmission and recovering the original analog data from the digital signal.

Question 4

Frequency modulation and phase modulation are special cases of ________ modulation.
A)PM
B)FM
C)angle
D)amplitude

Accepted Answer

Frequency modulation and phase modulation both belong to the category of angle modulation, which is a type of modulation where the angle of the carrier wave is varied in proportion to the modulating signal. Amplitude modulation, on the other hand, involves varying the amplitude of the carrier wave in proportion to the modulating signal. Therefore, options A, B, and D are incorrect answers.

Question 5

A distinction needs to be made between data rate (expressed in bits per second)and ________ rate (expressed in baud)when signal encoding techniques are used.

Accepted Answer

The answer of A distinction needs to be made between...

Question 6

A common encoding technique in which each of the two modulated streams is a BPSK signal at half the data rate of the original bit stream is ________.The combined signals have a symbol rate that is half the input bit rate.
A)MPSK
B)MFSK
C)QPSK
D)QAM

Accepted Answer

The technique described in the question is called Quadrature Phase Shift Keying (QPSK). QPSK is a form of phase modulation that can be thought of as two separate BPSK signals sent at the same time, but with their carrier waves out of phase with each other by 90 degrees (i.e., they are in quadrature). Each of the two modulated streams carries half of the bits of the original bit stream, and the combined signals have a symbol rate that is half the input bit rate. Therefore, the correct answer is C) QPSK.

Question 7

If digital signaling elements all have the same algebraic sign,all positive or all negative,then the signal is ________.
A)polar
B)unipolar
C)baseband
D)differential

Accepted Answer

If digital signaling elements all have the same algebraic sign, either positive or negative, then the signal is unipolar. Polar signaling refers to a system where the signal can have both positive and negative values. Baseband refers to a signal that has not been modulated, while differential signaling refers to a system that transmits data as differences between two signals.

Question 8

Analog data in electrical form can be transmitted as ________ signals easily and cheaply with voice transmission over voice grade lines.
A)carrier
B)broadband
C)baseband
D)modulating

Accepted Answer

Analog data can be transmitted as baseband signals easily and cheaply with voice transmission over voice grade lines due to the limited bandwidth available in these lines. Baseband signals refer to the original signal without any modulation, which in this case would be the analog data in electrical form. Carrier and modulating signals involve adding a higher frequency signal to the original signal for transmission, which would require a wider bandwidth than voice grade lines allow. Broadband signals also require a wider bandwidth than voice grade lines and are typically used for high-speed internet connections.

Question 9

The basis for ________ signaling is a continuous constant frequency signal known as the carrier signal.

Accepted Answer

The answer of The basis for ________ signaling is a...

Question 10

All modulation techniques involve operation on one or more of the three fundamental frequency domain parameters: amplitude,phase and _____.

Accepted Answer

The answer of All modulation techniques involve operation on one...

Question 11

Multiple signals,each at a different position on the spectrum,sharing the same transmission medium,is known as frequency division ________.

Accepted Answer

The answer of Multiple signals,each at a different position on...

Question 12

The ________ code has been specified for the IEEE 802.3 (Ethernet)standard for baseband coaxial cable and twisted pair bus LANs.
A)Manchester
B)HDB3
C)differential Manchester
D)NRZ

Accepted Answer

Manchester code is the specific code used for the IEEE 802.3 (Ethernet) standard for baseband coaxial cable and twisted pair bus LANs. HDB3 and differential Manchester are used in other types of communication systems, while NRZ (Non-Return-to-Zero) is not a code but a scheme for transmitting binary data.

Question 13

Because of their simplicity and relatively low frequency response characteristics,________ codes are commonly used for digital magnetic recording.
A)NRZ
B)AMI
C)VSES
D)B8ZS

Accepted Answer

NRZ (Non-Return-to-Zero) codes have a simple structure and are ideal for digital magnetic recording due to their low frequency response characteristics. This makes them a common choice for magnetic storage devices like hard disk drives and magnetic tape drives. AMI (Alternate Mark Inversion) codes are also commonly used, but their voltage levels can cause issues with signal integrity and noise. VSES (Variable-Length Sub-Echo Signal) and B8ZS (Binary 8-Zero Substitution) codes have more complex structures and are typically used for long-distance communication over optic fiber cables, rather than magnetic recording.

Question 14

The ________ rate,expressed in baud,is the rate at which the signal level is changed.

Accepted Answer

The answer of The ________ rate,expressed in baud,is the rate...

Question 15

The three basic encoding or modulation techniques for transforming digital data into analog signals are amplitude shift keying,phase shift keying,and ________.

Accepted Answer

The answer of The three basic encoding or modulation techniques...

Question 16

In ________ signaling one logic state is represented by a positive voltage level and the other by a negative voltage level.

Accepted Answer

The answer of In ________ signaling one logic state is...

Question 17

NRZI is an example of ________ encoding.

Accepted Answer

The answer of NRZI is an example of ________ encoding....

Question 18

In ________ the phase of the carrier signal is shifted to represent data.
A)MFSK
B)ASK
C)FSK
D)PSK

Accepted Answer

Phase Shift Keying (PSK) is a digital modulation technique where the phase of the carrier signal is shifted to represent binary data.

Question 19

A coding scheme that is commonly used in Europe and Japan is the ________.
A)B8ZS
B)AMI
C)amplitude shift keying
D)HDB3

Accepted Answer

HDB3 (High Density Bipolar of Order 3) is a coding scheme commonly used in Europe and Japan. B8ZS (Bipolar with 8 Zeros Substitution) and AMI (Alternate Mark Inversion) are commonly used in North America. Amplitude Shift Keying is a modulation technique, not a coding scheme.

Question 20

The binary 1 represented by the absence of a line signal and the binary 0 by alternating positive and negative pulses is ________.
A)pseudoternary
B)NRZ-L
C)bipolar-AMI
D)differential Manchester

Accepted Answer

Pseudoternary encoding represents binary 1 by the absence of a line signal and binary 0 by alternating positive and negative pulses, distinguishing it from other encoding schemes that use different methods for signal representation.

Quiz 5: Signal Encoding Techniques

In the ________ scheme,a binary 0 is represented by no line signal and a binary 1 is represented by a positive or negative pulse.The binary 1 pulses must alternate in polarity.

There is a transition at the middle of each bit period in the ________ biphase coding technique.The midbit transition serves as a clocking mechanism and also as data.A low-to-high transition represents a 1,and a high-to-low transition represents a 0.

The device used for converting analog data into digital form for transmission,and subsequently recovering the original analog data from the digital,is a ________.

Frequency modulation and phase modulation are special cases of ________ modulation.

A distinction needs to be made between data rate (expressed in bits per second)and ________ rate (expressed in baud)when signal encoding techniques are used.

A common encoding technique in which each of the two modulated streams is a BPSK signal at half the data rate of the original bit stream is ________.The combined signals have a symbol rate that is half the input bit rate.

If digital signaling elements all have the same algebraic sign,all positive or all negative,then the signal is ________.

Analog data in electrical form can be transmitted as ________ signals easily and cheaply with voice transmission over voice grade lines.

The basis for ________ signaling is a continuous constant frequency signal known as the carrier signal.

All modulation techniques involve operation on one or more of the three fundamental frequency domain parameters: amplitude,phase and _____.

Multiple signals,each at a different position on the spectrum,sharing the same transmission medium,is known as frequency division ________.

The ________ code has been specified for the IEEE 802.3 (Ethernet) standard for baseband coaxial cable and twisted pair bus LANs.

Because of their simplicity and relatively low frequency response characteristics,________ codes are commonly used for digital magnetic recording.

The ________ rate,expressed in baud,is the rate at which the signal level is changed.

The three basic encoding or modulation techniques for transforming digital data into analog signals are amplitude shift keying,phase shift keying,and ________.

In ________ signaling one logic state is represented by a positive voltage level and the other by a negative voltage level.

NRZI is an example of ________ encoding.

In ________ the phase of the carrier signal is shifted to represent data.

A coding scheme that is commonly used in Europe and Japan is the ________.

The binary 1 represented by the absence of a line signal and the binary 0 by alternating positive and negative pulses is ________.