CCW
Amplitude Modulation and Communication Systems Quiz
Test your knowledge on amplitude modulation and communication systems with our comprehensive quiz! This quiz consists of 100 questions covering various topics such as modulation techniques, signal processing, and digital communication.
Whether you are a student, teacher, or professional in the field, this quiz will challenge your understanding and expand your knowledge. Get ready to dive into:
- AM signal power calculations
- Modulation indices
- Phase shift keying systems
- Noise and distortion in communication
For 100% modulation, power in each sideband is ________ of that of carrier.
50%
25%
70%
Calculate power in each sideband, if power of carrier wave is 176W and there is 60% modulation in amplitude modulated signal?
13.36W
67W
15.84W
The upper and lower sideband frequencies for 5KHz amplitude modulation with a 30KHz carrier frequency will be?
35KHz and 25KHz
34KHz and 24KHz
0.35KHz and 0.25KHz
A 400W carrier wave is modulated to a depth of 65%. Find the total power of modulated wave?
512.5W
493W
484.5W
If modulation index of an AM wave is increased from 1.5 to 2, then the transitted power _______
Remains same
Increases by 41%
Increases by 50%
Bandwidth required in SSB-SC signal is
2 fm
Fm
> 2fm
What is the modulation index of a system with modulating frequency 75kHz and maximum frequency deviation 15kHz?
5
7
3
According to Carson’s rule, what is the bandwidth of the signal with a deviation of 30kHz and a maximum modulating signal of frequency 5kHz?
70kHz
90kHz
100kHz
Companding is used
To overcome quantizing noise in PC
In PCM transmitters, to allow amplitude limiting in the receivers
To protect small signals in PCM from quantizing distortion.
The signal-to quantization noise ratio in PCM system depends upon
Sampling rate
Number of quantization levels
Message signal bandwidth
The main advantage of PCM system is
Lower bandwidth
Lower power
Lower noise
In a DM system, the granular (idling) noise occurs when the modulating signal
Increase rapidly
Remains constant
Decreases rapidly
The non-uniform quantization leads to
Reduction in transmission bandwidth
Increase in maximum SNR
Increase in SNR for low level signals
In a PCM system, the number of quantization levels are 16 and the maximum signal frequency is 4 kHz, the bit transmission rate is
32 kpbs
16 kbps
64 bps
In a PCM system, the amplitude levels are transmitted in a 7 unit code. The sampling is done at the rate of 10 kHz. The BW should be
5 kHz
35 kHz
70 kHz
The type of distortion which occurs in delta modulation is
Slope overload distortion
Granular noise
Slope overload distortion & Granular noise
Gaussian process is a
Wide sense stationary process
Strict sense stationary process
Both 1 and 2
Let X be a random variable with probability distribution function f (x)=0.2 for |x| <1 = 0.1 for 1 < |x| < 4 = 0 otherwise The probability P (0.5 < x < 5) is _____
0.3
0.5
0.4
If E denotes the expectation the variance of a random variable X is denoted as?
E(X)2
E(X2 )-(E(X))2
E(X2)
In Binary Phase Shift Keying system, the binary symbols 1 and 0 are represented by carrier with phase shift of
π/2
π
2π
0
BPSK system modulates at the rate of
1 bit/ symbol
2 bit/ symbol
4 bit/ symbol
None of the above
The binary waveform used to generate BPSK signal is encoded in
Bipolar NRZ format
Manchester coding
Differential coding
None of the above
QPSK is a modulation scheme where each symbol consists of
4 bits
2 bits
1 bit
M number of bits, depending upon the requirement
The data rate of QPSK is ___________ of BPSK.
Thrice
Four times
Twice
Same
A nyquist pulse is the one which can be represented by _____ shaped pulse multiplied by another time function.
Sine
Cosine
Sinc
None of the mentioned
QPSK system uses a phase shift of
π
π /2
π /4
2 π
In coherent detection of signals,
Local carrier is generated
Carrier of frequency and phase as same as transmitted carrier is generated
The carrier is in synchronization with modulated carrier
All of the above
The minimum nyquist bandwidth for the rectangular spectrum in raised cosine filter is
2T
1/2T
T2
2/T
Roll off factor is the fraction of
Excess bandwidth and absolute bandwidth
Excess bandwidth and minimum nyquist bandwidth
Absolute bandwidth and minimum nyquist bandwidth
None of the mentioned
Equalization process includes
Maximum likelihood sequence estimation
Equalization with filters
Maximum likelihood sequence estimation & Equalization with filters
None of the mentioned
The filters used with the equalizer is of ______ types.
Feed forward
Feed backward
Feed forward and feedback
None of the mentioned
The detector that minimizes the error probability is called as
Maximum likelihood detector
Minimum likelihood detector
Maximum & Minimum likelihood detector
None of the mentioned
An error in binary decision making occurs when the channel noise is
Greater than the optimum threshold level
Lesser than the optimum threshold level
Greater or Lesser than the optimum threshold level
None of the mentioned
Matched filter provides _____ signal to noise ratio.
Maximum
Minimum
Zero
Infinity
Entropy is
Average information per message
Information in a signal
Amplitude of signal
All of the above
The relation between entropy and mutual information is
I(X;Y) = H(X) - H(X/Y)
I(X;Y) = H(X/Y) - H(Y/X)
I(X;Y) = H(X) - H(Y)
I(X;Y) = H(Y) - H(X)
Code rate r, for k information bits and n as total bits, is defined as
R= k/n
K=n/r
R=k*n
N=r*k
For M equally likely messages, M>>1, if the rate of information R > C, the probability of error is
Arbitrarily small
Close to unity
Not predictable
Unknown
For M equally likely messages, the average amount of information H is
H= log10M
H= log2M
H= log10M2
H= 2log10M
The capacity of Gaussian channel is
C= 2B(1+S/N) bits/s
C= B2 (1+S/N) bits/s
C= B(1+S/N) bits/s
C= B(1+S/N)2 bits/s
Orthogonality of two codes means
The integrated product of two different code words is zero
The integrated product of two different code words is one
The integrated product of two same code words is zero
None of the above
Equalization method which is done by tracking a slowly time varying channel response is
Preset equalization
Adaptive equalization
Variable equalization
None of the mentioned
For AWGN, the noise variance is
N0
N0/2
2N0
N0/4
As the eye opens, ISI _______
Increases
Decreases
Remains the same
None of the mentioned
The correlating detector is also known as
Maximum likelihood detector
Minimum likelihood detector
Maximum & Minimum likelihood detector
None of the mentioned
The limit which represents the threshold Eb/N0 value below which reliable communication cannot be maintained is called as
Probability limit
Error limit
Shannon limit
Communication limit
A bit stream would be portioned into an even stream and an odd stream in which of these systems?
FSK
QPSK
MSK
BPSK
The odd part of a signal x(t) is?
X(t)+x(-t)
X(t)-x(-t)
(1/2)*(x(t)+x(-t))
(1/2)*(x(t)-x(-t))
If x(n)=(0,0,1,1,1,1,1,0) then x(3n+1) is?
(0,1,0,0,0,0,0,0)
(0,0,1,1,1,1,0,0)
(1,1,0,0,0,0,0,0)
The process of converting discrete-time continuous valued signal into discrete- time discrete valued (digital) signal is known as ____________
Sampling
Quantization
Coding
If a signal x(t) is processed through a system to obtain the signal (x(t) ), then the system is said to be __
Linear
Non-linear
Exponential
What is the ROC of the signal x(n)=δ(n-k), k>0?
Z=0
Z=∞
Entire z-plane, except at z=0
Entire z-plane, except at z=∞
What is the ROC of z-transform of an two sided infinite sequence?
|z|>r1
|z|
R2<|z|
Is the discrete time LTI system with impulse response h(n)=a (n) (|a| < 1) BIBO stable?
True
False
If x(n) is causal, then
X(-1)
X(1)
X(0)
If x (n)={1,2,3} and x (n)={1,1,1}, then what is the convolution sequence of the given two signals?
{1,2,3,1,1}
{1,2,3,4,5}
{1,3,5,6,2}
{1,2,6,5,3}
What are the values of z for which the value of X(z)=∞?
Poles
Zeros
Solutions
If x(n) and X(k) are an N-point DFT pair, then X(k+N)=?
X(-k)
-X(k)
X(k)
What is the circular convolution of the sequences X (n)={2,1,2,1} and x (n)= {1,2,3,4}?
{14,14,16,16}
{14,16,14,16}
{16,16,14,14}
Overlap add and Overlap save are the two methods for linear FIR filtering a long sequence on a block-by-block basis using DFT.
True
False
WN^ k+n/2+ =?
Wn^k
-Wn^k
Wn^-k
Which of the following is true regarding the number of computations required to compute an N-point DFT?
N 2 complex multiplications and N(N-1) complex additions
N 2 complex additions and N(N-1) complex multiplications
N 2 complex multiplications and N(N+1) complex additions
Hexadecimal and BCD numbers of decimal number 43 are
B2, 0100 0110
2B, 0100 0011
2B, 0011 0100
B2, 0100 0100
How many 3-line-to-8-line decoders are required for a 1-of-32 decoder?
1
2
4
8
How many flip-flops are required to produce a divide-by-128 device?
1
4
6
7
What is the modulus of 3-bit Johnson’s counter
3
8
6
None of the above
The 1’s complement of (+5)10 is
0101
1010
1011
1101
The Canonical form of Y=AB’C+A’BC+AB is Y(A,B,C)=
Σm (1,3,5,6,7)
Σm (0,5,6,7)
Σm (3,5,7)
Σm (3,5,6,7)
LS in 74LS00 stands for
Low Schottky
Low power
Low sound
Low switching
When Qn=0 and Qn+1=0
J=0, K=X
D=0
T=0
All of above
In a 3bit ring counter with Q0 as LSB and Q2 as MSB
Q2 is connected to D0
B) Q2’ is connected to D0
Q0 is connected to D2
Q0’ is connected to D2
G ray code of (010101)2 is
010101
101011
011111
110001
F( A,B,C)=Σm(0,2,4,6) reduces to
A’
C’
A’B
AB
N OT gate using CMOS can be implemented using
One PMOS and Two NMOS
Two PMOS and Two NMOS
One PMOS and Three NMOS
One PMOS and One NMOS
A mod 5 counter counts from
0 to 6
0 to 4
0 to 5
1 to 4
Which of the following sequence does not occur in a Johnson counter
Q2Q1Q0=000
Q2Q1Q0=100
Q2Q1Q0=111
Q2Q1Q0=101
Which A/D converter is considered to be simplest, fastest and most expensive?
Servo converter
Counter type ADC
Flash type ADC
All of the mentioned
An Astable Multivibrtor is also known as
One Shot Multivibrator
Free-Running Multivibrator
Bistable Multivibrator
None of the above
How a triangular wave generator is derived from square wave generator?
Connect oscillator at the output
Connect Voltage follower at the output
Connect differential at the output
Connect integrator at the output
Which circuit converts irregularly shaped waveform to regular shaped waveforms
Schmitt trigger
Voltage limiter
Comparator
None of the mentioned
Narrow band-pass filters are defined as
Q < 10
Q=10
Q>10
None of the mentioned
The purpose of level shifter in Op-amp internal circuit is to
Adjust DC voltage
Increase impedance
Provide high gain
Decrease input resistance
______________is the process of setting a transistors DC operating voltage or current conditions to the correct level.
Regulation
Biasing
Stabilisation
Shifting
An op-amp is a direct coupled high gain amplifier.
TRUE
FALSE
OPAMP can operate on
AC
DC
BOTH
NONE
The voltage present at the output of an op-amp when its differential input voltage is zero is called as?
Open loop voltage gain
Common Mode Rejection Ratio
Output offset voltage
Closed offset voltage
CMRR can be represented as?
The addition of the closed loop differential gain and the common mode gain
The multiplication of the closed loop differential gain and the common mode gain
The subtraction of the closed loop differential gain and the common mode gain
The ratio of the closed loop differential gain and the common mode gain
Ideal Opamp has the following characteristics
Rin=infinity, A=inifinity, Ro=infinity
Rin=0, A=inifinity, Ro=0
Rin=infinity, A=inifinity, Ro=0
Rin=0, A=inifinity, Ro=infinity
Voltage Follower
It has hign input impedance and low output impedance
Its a non inverting amplifier with negative feedback
Its voltage gain is unity
All of the above
Certain pulse measures 10ms and has a period of 50ms. Duty cycle is
5%
10%
20%
50%
What is Barkhausen criterion for oscillation?
Aß > 1
Aß < 1
Aß = 1
Aß ≠ 1
Express the requirement for oscillation in polar form
Aß =1∠360o
Aß =1∠90o
Aß =1∠pi
Aß =1∠270o
Name the type of noise signal present in the oscillation
Schmitt noise
Schottky noise
Saturation noise
Determine the time period of a monostable 555 multivibrator.
T = 0.33RC
T = 1.1RC
T = RC
A monostable multivibrator has R = 120kΩ and the time delay T = 1000ms, calculate the value of C
0.9μF
1.32μF
7.5μF
A 555 timer in monostable application mode can be used for
Pulse position modulation
Speed control and measurement
Digital phase detector
Free running frequency of Astable multivibrator?
F=1.45/(RA+2RB)C
F=1.45(RA+2RB)C
F=1.45C/(RA+2RB)
Astable multivibrator operating at 150Hz has a discharge time of 2.5m. Find the duty cycle of the circuit.
50%
70%
37.5%
{"name":"CCW", "url":"https://www.quiz-maker.com/QPREVIEW","txt":"Test your knowledge on amplitude modulation and communication systems with our comprehensive quiz! This quiz consists of 100 questions covering various topics such as modulation techniques, signal processing, and digital communication.Whether you are a student, teacher, or professional in the field, this quiz will challenge your understanding and expand your knowledge. Get ready to dive into:AM signal power calculationsModulation indicesPhase shift keying systemsNoise and distortion in communication","img":"https:/images/course1.png"}