Question 1
Analogue switches provides
A. Good bandwidth
B. Low distortion
C. Low cost
D. All of the mentioned
View Answer
Answer: Option D
Explanation:
Some of the features of analogue switches are good bandwidth, low cost, low distortion, lower reliability.
Question 2
Delta modulation is ______ conversion.
A. Analog to digital
B. Digital to analog
C. Analog to digital and digital to analog
D. None of the mentioned
View Answer
Answer: Option C
Explanation:
Delta modulation is the process of analog to digital and digital to analog conversion technique used for transmission of voice signals.
Question 3
In bipolar codes, pulses can be
A. Positive
B. Negative
C. Absent
D. All of the mentioned
View Answer
Answer: Option D
Explanation:
In bipolar codes, the pulses can be positive, negative or absent.
Question 4
In channel encoding procedure
A. Redundancy bits are added
B. Errors are corrected
C. Redundancy bits are added & Errors are corrected
D. None of the mentioned
View Answer
Answer: Option C
Explanation:
In channel encoding includes addition of redundancy to the signal such that any bit errors can be corrected.
Question 5
In time division system, the actual switch is called as
A. Speech memory
B. Cross point
C. Connecting point
D. None of the mentioned
View Answer
Answer: Option A
Explanation:
In time division, actual switch is called as speech memory and in space division actual switch is called as cross point.
Question 6
In time division, connection is established using
A. Data exchange
B. Galvanic connection
C. Data exchange & Galvanic connection
D. None of the mentioned
View Answer
Answer: Option A
Explanation:
In time division, connection is established using data exchange and in space division it is established using galvanic connections.
Question 7
Modulation process includes
A. Analog to digital conversion
B. Digital to analog conversion
C. All of the mentioned
D. None of the mentioned
View Answer
Answer: Option B
Explanation:
Modulation procedure includes digital to analog conversion which produces a continuous time signal that can be sent through the channel.
Question 8
Operations performed by switching system
A. Path establishment
B. Information exchange
C. Tariff computation
D. All of the mentioned
View Answer
Answer: Option D
Explanation:
Operations performed by switching network are path establishment, information exchange, tariff computation, maintenance, billing etc.
Question 9
Properties used to determine stream’s fidelity
A. Sampling rate
B. Bit depth
C. Sampling rate & Bit depth
D. None of the mentioned
View Answer
Answer: Option C
Explanation:
Two basic properties to determine stream’s fidelity are bit depth and sampling rate, number of times per second that samples are taken.
Question 10
Space division has dedicated
A. Paths
B. Time slots
C. Paths & Time slots
D. None of the mentioned
View Answer
Answer: Option A
Explanation:
Space division has dedicated paths and time division has dedicated time slots.
Question 11
Switching exists in
A. Point to point communication
B. Broadcast communication
C. Point to point & Broadcast communication
D. None of the mentioned
View Answer
Answer: Option A
Explanation:
Circuit connection in point to point communication is called as switching. Switching does not exist in broadcast communication or network.
Question 12
The demodulator in delta modulation technique is
A. Differentiator
B. Integrator
C. Quantizer
D. None of the mentioned
View Answer
Answer: Option B
Explanation:
The demodulator used in delta modulation is a simple form of integrator.
Question 13
To achieve high signal to noise ratio, delta modulation must use
A. Under sampling
B. Over sampling
C. Aliasing
D. None of the mentioned
View Answer
Answer: Option B
Explanation:
To achieve high signal to noise ratio, delta modulation must use over sampling techniques.
Question 14
When probability of receiving a symbol is 1 then how much information will be obtained?
A. Little information
B. Much information
C. No information
D. None of the mentioned
View Answer
Answer: Option C
Explanation:
When the probability of receiving a symbol is 1 then the information obtained is zero.
Question 15
In amplitude modulation, which of the following varies?
A. Frequency of the carrier
B. Frequency of the information signal
C. Amplitude of the carrier wave
D. Amplitude of the information signal
View Answer
Answer: Option C
Explanation:
In amplitude modulation, the amplitude of the carrier wave is modulated with respect to the information signal. The frequency and the phase of both the carrier and the information signal remain constant.
Question 16
In frequency modulation, carrier frequency is always greater than baseband frequency.
A. True
B. False
View Answer
Answer: Option A
Explanation:
In frequency modulation, the baseband signal is overlapped or impressed in the carrier signal. The carrier can never have a lower frequency than the baseband signal as it would result in a huge data loss of the baseband signal.
Question 17
The information signal is otherwise referred to as ___________
A. Digital signal
B. Analog signal
C. Baseband signal
D. Broadband signal
View Answer
Answer: Option C
Explanation:
The information signal, regardless of analog or digital type, is referred to as baseband signals. It could be voice, video or digital data and is modulated before transmission. In some case, baseband signals can be transmitted without modulation.
Question 18
The process of making the signal more compatible with the medium is called as?
A. Modulation
B. Transmission
C. Encrypting
D. Multiplexing
View Answer
Answer: Option A
Explanation:
Modulation is the process of making the information signal more compatible with the medium. Modulation is the reason why we can have different channels on radio.
Question 19
Voice signals cannot be directly transmitted by radio.
A. True
B. False
View Answer
Answer: Option A
Explanation:
Baseband signals are, in many cases, incompatible with the medium. Theoretically, it is possible to transmit voice signals directly by radio, but due to the low frequency of these waves the antenna size required form transmission is too big.
Question 20
What type of multiplexing is used in mobile phones?
A. Frequency division multiplexing
B. Time division multiplexing
C. Code division multiplexing
D. Phase multiplexing
View Answer
Answer: Option C
Explanation:
In code-division multiplexing, the signals to be transmitted are converted to digital data that is then uniquely coded with a faster binary code. The signals modulate a carrier on the same frequency. All use the same communications channel simultaneously. The unique coding is used at the receiver to select the desired signal.
Question 21
What type of multiplexing is used in serial buses?
A. Time division multiplexing
B. Code division multiplexing
C. Frequency division multiplexing
D. Phase multiplexing
View Answer
Answer: Option A
Explanation:
In serial buses, time division multiplexing is used to split the digital data, which is in binary numbers, into individual bits which occupy a particular time slot and is transmitted. The use of serial buses increases the limit on transmission speed and reduces noise.
Question 22
Which one of the following is not a type of modulation?
A. Frequency modulation
B. Amplitude Modulation
C. Pulse modulation
D. Phase amplitude modulation
View Answer
Answer: Option C
Explanation:
Modulation is of three types, frequency modulation, amplitude modulation and phase modulation. Pulse modulation is a type of amplitude modulation.
Question 23
Which one of the following is not true with respect to amplitude modulation?
A. Less noise
B. Longer range
C. Lower bandwidth
D. Less complex circuits
View Answer
Answer: Option A
Explanation:
Although AM is much simpler and has a wider range due to atmospheric propagation, one of its major disadvantages is due to noise. Noise directly affects the amplitude of the signal and its hard to retrieve the original information.
Question 24
You have 5 information signals and only one transmitter. What technique will help in transmitting all the 5 signals?
A. Frequency modulation
B. Multiplexing
C. Amplification
D. Amplitude modulation
View Answer
Answer: Option B
Explanation:
Multiplexing is the process of transmitting more than one signal via a common transmitting medium. A device called a multiplexer is used for this purpose. The signal can be demultiplexed at the receiver end to retrieve the original information.