A rate 1/2 convolution code with dfrec = 10 is used to encode a data sequence occurring at a rate of 1 kbps. The modulation is binary PSK. The DS spread spectrum sequence has a chip rate of 10 MHz.The coding gain is?

A rate 1/2 convolution code with dfrec = 10 is used to encode a data sequence occurring at a rate of 1 kbps. The modulation is binary PSK. The DS spread spectrum sequence has a chip rate of 10 MHz. The processing gain is?

A

14 dB

B

37 dB

C

58 dB

D

104 dB

A source produces binary data at the rate of 10 kbps. The binary symbols are represented as shown in the figure.
Digital Communication mcq question image

Digital Communication mcq question image

The source output is transmitted using two modulation schemes, namely Binary PSK (BPSK) and Quadrature PSK (QPSK). Let and B2 be the bandwidth requirements of BPSK and QPSK respectively. Assuming that the bandwidth of the above rectangular pulses is 10 kHz, B₁ and B₂ are

A

B₁ = 20 kHz, B₂ = 20 kHz

B

B₁ = 10 kHz, B₂ = 20 kHz

C

B₁ = 20 kHz, B₂ = 10 kHz

D

B₁ = 10 kHz, B₂= 10 kHz

Match List I with List II List I List II A. Selective coding I. To discover the most significant or frequent initial code that makes the most analytical sense B. Initial coding II. The procedure of selecting the core category, Systematically relating it to other categories, validating their relationships, and filling in categories that need further refinement and development C. Focused coding III. It specifies possible relationships between categories, these are integrative D. Theoretical coding IV. Comparing data with data, staying close to and remain open to exploring what is happening in data, construct and keep the code short, simple, precise and active. Choose the correct answer from the options given below:

A

A ‐ II, B ‐ IV, C ‐ I, D ‐ III

B

A ‐ IV, B ‐ I, C ‐ III, D ‐ II

C

A ‐ I, B ‐ III, C ‐ II, D ‐ IV

D

A ‐ III, B ‐ II, C ‐ IV, D ‐ I

Consider the following types of modulation: 1. Amplitude modulation 2. Frequency modulation 3. Phase modulation 4. Pulse modulation Which of the above modulation are used for telecasting TV programs?

A

2 and 3

B

3 and 4

C

1 and 2

D

1 and 4

Statement (I): M-ary PSK can be used to transit digital data over a non-linear bandpass channel, whereas M-ary QAM requires the use of a linear channel. Statement (II): M-ary PSK and M-ary QAM are examples of non-linear modulation.

A

Both Statement (I) and Statement (II) are individually true and Statement (II) is the correct explanation of Statement (I).

B

Both Statement (I) and Statement (II) are individually true, but Statement (II) is not the correct explanation of Statement (I).

C

Statement (I) is true, but Statement (II) is false.

D

Statement (I) is false, but Statement (II) is true.

Consider a binary memoryless channel characterized by the transition probability diagram shown in the figure. The channel is
Information Theory and Coding mcq question image

Information Theory and Coding mcq question image

A

Lossless

B

Noiseless

C

Useless

D

Deterministic

Consider the following statements regarding modulation : 1. The communication systems, where a weak signal is transmitted by the use of a modulation is essential in carrier signal. 2. When the frequency of the high frequency signal is varied in accordance with the intensity of the low-frequency weak signal, the modulation is said to be frequency modulation. 3. The process of recovering original baseband signal from the modulated signal is called phase modulation. Which of the above statements are correct ?

A

1 and 3 only

B

1 and 2 only

C

2 and 3 only

D

1, 2 and 3

The data rate can vary from 50 Kbps for mono signal to nearly 500 Kbps for stereo sounds in digital satellite television.

A

True

B

False

Block codes can achieve a larger coding gain than convolution coding.

A

True

B

False

Coherent orthogonal binary FSK modulation is used to transmit two equiprobable symbol waveforms s₁(t) = αcos2πf₁t & s₂(t) = αcos2πf₂t₁ where α = 4 mV. Assume an AWGN channel with two-sided noise power spectral density $$\frac{{{N_0}}}{2} = 0.5 \times {10^{ - 12}}W/Hz.$$ Using an optimal receiver and the relation $$Q\left( v \right) = \frac{1}{{\sqrt {2\pi } }}\int\limits_v^\infty {{\theta ^{\frac{{{u^2}}}{2}}}du,} $$ the bit error probability for a data rate of 500 kbps is

A

Q(2)

B

$$Q\left( {2\sqrt 2 } \right)$$

C

Q(4)

D

$$Q\left( {4\sqrt 2 } \right)$$

A rate 1/2 convolution code with dfrec = 10 is used to encode a data sequence occurring at a rate of 1 kbps. The modulation is binary PSK. The DS spread spectrum sequence has a chip rate of 10 MHz.The coding gain is?

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