# Electrical measurements-Digital Communications MCQs set/12 Sample Test,Sample questions

## Question: ```Acquisition is a ______ operation. ```

1.Linear

2.Non linear

3.Linear & Non linear

4. None of the mentioned

## Question: ```As the synchronization levels increases, cost ```

1.Decreases

2.Increases

3.Remains the same

4.None of the mentioned

## Question: ```Average energy per bit is given by ```

1.average energy symbol/log2 M

2.average energy symbol * log2 M

3.log2 M/ Average energy symbol

4.none of the mentioned

## Question: ```Coherent modulation requires ____ level of synchronization. ```

1.One

2.Two

3.Three

4.None of the mentioned

## Question: ```Continuous phase modulation has ```

1.More bandwidth efficiency

2.More smoothness

3.More bandwidth efficiency & smoothness

4.None of the mentioned

## Question: ```CPM has ```

1.Narrower bandwidth

2.Wider bandwidth

3.More bandwidth requirement

4.None of the mentioned

## Question: ```Entropy calculation returns ```

1.Random variable

2. Deterministic number

3.Random number

4.None of the mentioned

1.Sum

2.Product

3.Sum of squares

4.Average

1.One

2.Two

3.Four

4.Six

## Question: ```For block codes _____ is necessary. ```

1.Phase synchronization

2.Frequency synchronization

3.Frame synchronization

4.None of the mentioned

## Question: ```FSK reception is ```

1.Phase Coherent

2.Phase non coherent

3.Phase Coherent & non coherent

4.None of the mentioned

## Question: ```FSK reception uses ```

2.PLL

4.None of the mentioned

## Question: ```Gaussian noise has _____ power spread _____ over all frequencies. ```

1.Zero, uniformly

2.Zero, non uniformly

3.Infinite, uniformly

4.Infinite, non uniformly

## Question: ```If we correlate the received signal with any one of the two orthogonal function, the obtained inner product will be ```

1.In phase

3.Zero

4.Cannot be determined

1.In phase

4.Unity

## Question: ```In non coherent reception _____ is measured. ```

1.Phase

2.Energy

3.Power

4.None of the mentioned

## Question: ```In open loop method, the time reference error __________ with respect to time. ```

1.Increases exponentially

2.Decreases exponentially

## Question: ```In phase lock which parameter is synchronized ```

1.Frequency

2.Phase

3.Frequency & Phase

4.None of the mentioned

## Question: ```In VCO the output frequency is a linear function of its input ```

1.Frequency

2.Voltage

3.Time period

4. None of the mentioned

## Question: ```In which modulation schemes, the spreading of spectrum occurs? ```

1.Frequency modulation

2.Amplitude modulation

3.Frequency & Amplitude modulation

4.None of the mentioned

## Question: ```Jamming is caused by ```

1.Multipath

2.Natural phenomena

3.Multipath & Natural phenomena

4.None of the mentioned

## Question: ```Matched filter is a _____ technique. ```

1.Modulation

2.Demodulation

3.Modulation & Demodulation

4.None of the mentioned

## Question: ```Non coherent system requires ```

1.Phase synchronization

2.Frequency synchronization

3.Phase & Frequency synchronization

4.None of the mentioned

## Question: ```Phase locked loops consists of ```

1.Phase detectors

2.Loop filter

3. Voltage controlled oscillator

4.All of the mentioned

## Question: ```PLL designs have ```

1.First order loop

2.Second order loop

3.Higher order loop

4.None of the mentioned

## Question: ```QAM uses ______ as the dimensions. ```

1.In phase

4.None of the mentioned

## Question: ```Simulation is used to determine ```

1.Bit error rate

2.Symbol error rate

3.Bit error

4.Symbol error

## Question: ```Spread spectrum signals are used for ```

1.Ranging

2.Determination of position

3.Ranging & Determination of position

4.None of the mentioned

## Question: ```Synchronization is used in system which has ```

1.Non coherent modulation techniques

2.Many users accessing

3.Non coherent modulation techniques & Many users accessing

4.None of the mentioned

## Question: ```The number of filters in CPM receiver structure is ```

1.LM

2.ML

3.M/L

4.None of the mentioned

## Question: ```The radio meter consists of ```

1.Low pass filter

2.High pass filter

3.Band pass filter

4.Band reject filter

## Question: ```The synchronization necessary for BPSK is ```

1.Frequency tracking

2.Bit timing

3.Phase tracking

4.All of the mentioned

## Question: ```The system which has ______ signal to noise ratio can tolerate larger timing error. ```

1.Large

2.Small

3.Large & Small

4.None of the mentioned

## Question: ```To avoid the loop to be driven to lock, the sweep rate should be ```

1.Smaller

2.Larger

3.It does not depend on it

4.None of the mentioned

## Question: ```Transmitter synchronization implies ```

1.One way communication

2.Two way communication

3.One & Two way communication

4.None of the mentioned

## Question: ```Uncertainty in the delay measurement is _________ to the bandwidth of signal pulse. ```

1.Directly proportional

2.Inversely proportional

3.Not related

4.None of the mentioned

## Question: ```What is the function of the edge detector? ```

1.Differentiation

2.Rectification

3.Differentiation & Rectification

4.None of the mentioned

## Question: ```When a terminal is able to utilize the measurements made on the return link it is called as ```

1.Open loop method

2.Closed loop method

3.Quasi close loop method

4.None of the mentioned

1.Two times

2.Four times

3.0.5 times

4.8 times

## Question: ```Which FSK has no phase discontinuity? ```

1.Continuous FSK

2.Discrete FSK

3.Uniform FSK

4.None of the mentioned

## Question: ```Which is called as on-off keying? ```

1.Amplitude shift keying

2.Uni-polar PAM

3.Amplitude shift keying & Uni-polar PAM

4.None of the mentioned

## Question: ```Which method has fast acquisition and can work without return link? ```

1.Open loop method

2.Closed loop method

3.Open & Closed loop method

4.None of the mentioned

## Question: ```Which method has two way link? ```

1.Open loop method

2.Closed loop method

3.Open & Closed loop method

4.None of the mentioned

## Question: ```Which method is more accurate? ```

1.Closed loop synchronizer

2.Open loop synchronizer

3.Closed & Open loop synchronizer

4.None of the mentioned

## Question: ```Which method needs precorrect time? ```

1.Open loop method

2.Closed loop method

3.Open & Closed loop method

4.None of the mentioned

## Question: ```Which method requires external authority and is inflexible? ```

1.Open loop method

2.Closed loop method

3.Open & Closed loop method

4.None of the mentioned

## Question: ```Which reduces the effective distance between signals in signal space? ```

1.Time error

2.Frequency offset

3.Time error & Frequency offset

4.None of the mentioned

## Question: ```Which system makes the detection difficult for all users other than the intended users? ```

1.Low probability of intercept

2.Low probability of detection

3.Low probability of intercept & detection

4.None of the mentioned

## Question: ```Which system uses QAM? ```

1.Digital microwave relay

2.Dial up modem

3.Digital microwave relay & Dial up modem

4.None of the mentioned

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