**Multiple Choice Questions **

**Unit 1**

- Data compression means to

- Increase
- Decrease
- Can’t say
- None of the above Answer

Correct option is B

- Data compression and encryption both work on binary

- False
- True Answer

Correct option is B

- What is compression?

- To compress something by pressing it very hardly
- To minimize the time taken for a file to be downloaded
- To reduce the size of data to save space
- To convert one file to another Answer

Correct option is C

- Data compression usually works by

- Deleting random bits data
- Finding repeating patterns Answer

Correct option is B

- Why data compressed?

- To optimise the data
- To reduce secondary storage space
- To reduce packet congestion on networks
- Both (B) and (C)

Correct option is D

- Which is a type of data compression?

- Resolution
- Zipping
- Inputting
- Caching

Correct option is B

- Data compression involves

- Compression only
- Reconstruction only
- Both compression and reconstruction
- None of the above

Correct option is C

- Based on the requirements of reconstruction, data compression schemes can be divided into

- 3
- 4
- 2
- 5

Correct option is C

- Lossless, lossy
- Lossy, lossless
- None of these

Correct option is B

- Lossy
- Lossless
- Both
- None of these

Correct option is B

- What is compression ratio?

- The ratio of the number of bits required to represent the data before compression to the number of bits required to represent the data after
- The ratio of the number of bits required to represent the data after compression to the number of bits required to represent the data before
- The ratio of the number of bits required to represent the data after reconstruction to the number of bits required to represent the data before
- The ratio of the number of bits required to represent the data before reconstruction to the number of bits required to represent the data after

Correct option is A

- Suppose storing an image made up of a square array of 256×256 pixels requires 65,536 bytes. The image is compressed and the compressed version requires 16,384 bytes. Then the compression ratio is

- 1:4
- 4:1
- 1:2
- 2:1

Correct option is B

- Lossy techniques are generally used for the compression of data that originate as analog signals, such as

- Speech
- Video
- Both
- None of these

Correct option is C

- If fidelity or quality of a reconstruction is

- High, small
- Small, small
- High, high
- None of the above Answer

Correct option is D

- The development of data compression algorithms for a variety of data can be divided into

- 2
- 3
- 4
- 5

Correct option is A

- Which of the following is true of lossy and lossless compression techniques?

- Lossless compression is only used in situations where lossy compression techniques can’t be used
- Lossy compression is best suited for situations where some loss of detail is tolerable, especially if it will not be detectable by a human
- Both lossy and lossless compression techniques will result in some information being lost from the original file
- Neither lossy nor lossless compression can actually reduce the number of bits needed to represent a file

Correct option is B

- Which of the following would not be suitable for Lossy Compression?

- Speech
- Video
- Text
- Image

Correct option is C

- Which of the following are not in a compressed format?

- MP3
- Bitmap
- MPEG
- JPEG

Correct option is B

- Information theory was given by

- Claude von Regan
- Claude Elwood Shannon
- Claude Monet
- Claude Debussy

Correct option is B

- The unit of information depends on the base of the log. If we use log base 2, the unit is

- Hartleys, nats, bits
- Hartleys, bits, nats
- Bits, nats, hartleys
- Bits, hartleys, nats

Correct option is C

- According to Claude Elwood Shannon’s second theorem, it is not feasible to transmit information over the channel with

- Large
- May be large or small
- Unpredictable
- Small

Correct option is D

- The essential condition/s for a good error control coding technique?

- Better error correcting capability
- Maximum transfer of information in bits/sec
- Faster coding & decoding methods
- All of the above

Correct option is D

- The prefix code is also called as

- Block code
- Convolutional code
- Parity code
- Instantaneous code

Correct option is D

- Self information should be

- Negative
- Positive
- Both
- None of these

Correct option is B

- A code in which no codeword is a prefix to another codeword is called as

- Prefix cod
- Parity code
- Convolutional code
- Block code

Correct option is A

- The set of binary sequences is called a

- Codewords, code
- Code, codewords
- None of these Answer

Correct option is B

- Full form of ASCII is

- American Standard Code for Information Intercaste
- American Standard Codewords for Information Interchange
- American Standard Code for Information Interchange
- American System Code for Information Interchange

Correct option is C

- Composite source models is a combination or composition of several sources. In which how many source being active at any given time?

- All
- Only one
- Only first three
- None of these

Correct option is B

- For models used in lossless compression, we use a specific type of Markov process called a

- Continous time Markov chain
- Discrete time Markov chain
- Constant time Markov chain
- None of the above

Correct option is B

- Markov model is often used when developing coding algorithms for

- Speech
- Image
- Both
- None of these

Correct option is C

- Which of the following compression type is supported by SQL Server 2014?
- Row
- Column
- Both row and column
- None of the mentioned

Correct option is C

- Point out the correct statement:

- The details of data compression are subject to change without notice in service packs or subsequent releases
- Compression is not available for system tables
- If you specify a list of partitions or a partition that is out of range, an error will be generated
- All of the mentioned

Correct option is D

- In which type of Data Compression, the integrity of the data is preserved?
- Lossy Compression
- Lossless Compression
- Both of the above
- None of the above

Correct option is B

- Which of the following are Lossless methods?
- Run-length
- Huffman
- Lempel Ziv
- All of the above

Correct option is D

- Which of the following are lossy methods?
- JPEG
- MPEG
- MP3
- All of the above

Correct option is D

- In how many parts we can divide audio and video services into broad categories?
- Two
- Three
- Four
- None of the above

Correct option is B

- Sequence of code assigned is called
- code word
- word
- byte
- nibble

Correct option is A

**Unit-II**

- Huffman codes are

- Parity
- Prefix
- Convolutional code
- Block code

Correct option is B

- The Huffman procedure is based on observations regarding optimum prefix codes, which is/are

- In an optimum code, symbols that occur more frequently (have a higher probability of occurrence) will have shorter codewords than symbols that occur less
- In an optimum code,thetwo symbolsthat occurleast frequently will havethe samelength
- Both (A) and (B)
- None of these

Correct option is C

- The best algorithms for solving Huffman codes

- Brute force algorithm
- Divide and conquer algorithm
- Greedy algorithm
- Exhaustive search

Correct option is C

- How many printable characters does the ASCII character set consists of?

- 128
- 100
- 98
- 90

Correct option is B

- The difference between the entropy and the average length of the Huffman code is called

- Rate
- Redundancy
- Power
- None of these

Correct option is B

- Unit of redundancy is

- bits/second
- symbol/bits
- bits/symbol
- none of these

Correct option is C

- The redundancy is zero when

- The probabilities are positive powers of two
- The probabilities are negative powers of two
- Both
- None of the above

Correct option is B

- Which bit is reserved as a parity bit in an ASCII set?

- Sixth
- Seventh
- Eighth
- Ninth

Correct option is C

- Bits are needed for standard encoding if the size of the character set is X

- X+1
- log(X)
- X
^{2} - 2X

Correct option is B

10. In Huffman coding, data in a tree always occur in

- Leaves
- Roots
- Left sub trees
- None of these

Correct option is A

11. An optimal code will always be present in a full tree?

- True
- False

Correct option is A

- Running time of the Huffman encoding algorithm is

- O(Nlog(C))
- O(Clog(C))
- O(C)
- O(log(C)) Answer

Correct option is B

- Running time of the Huffman algorithm, if its implementation of the priority queue is done using linked lists

- O(log(C))
- O(Clog(C))
- O(C
^{2}) - O(C)

Correct option is C

- The unary code for a positive integer n is simply n

- zero, ones
- ones, zero
- None of these

Correct option is B

- The unary code for 4 is

- 11100
- 11110
- 00001
- 00011

Correct option is B

- In the Tunstall code, all codewords are of

- different, equal
- equal, different
- none of these

Correct option is B

- Tunstall coding is a form of entropy coding used for

- Lossless data compression
- Lossy data compression
- Both
- None of these

Correct option is A

- The main advantage of a Tunstall code is that

- Errors in codewords do not propagate
- Errors in codewords propagate
- The disparity between frequencies
- None of these

Correct option is A

- Applications of Huffman Coding

- Text compression
- Audio compression
- Lossless image compression
- All of the above

Correct option is D

- An alphabet consist of the letters A, B, C and D. The probability of occurrence is P(A) = 0.4, P(B)= 0.1, P(C) = 0.2 and P(D) = 0.3. The Huffman code is

- A = 0 B = 111 C = 110 D = 10
- A = 0 B = 11 C = 10 D = 111
- A = 0 B = 111 C = 11 D = 101
- A = 01 B = 111 C = 110 D = 10

Correct option is A

- The basic idea behind Huffman coding is to
- compress data by using fewer bits to encode fewer frequently occuring characters
- compress data by using fewer bits to encode more frequently occuring characters
- compress data by using more bits to encode more frequently occuring characters
- expand data by using fewer bits to encode more frequently occuring characters

Correct option is B

- Huffman coding is an encoding algorithm used for
- lossless data compression
- broadband systems
- files greater than 1 Mbit
- lossy data compression

Correct option is A

- A Huffman encoder takes a set of characters with fixed length and produces a set of characters of
- random length
- fixed length
- variable length
- constant length

Correct option is C

- A Huffman code: A = 1, B = 000, C = 001, D = 01 , P(A) = 0.4, P(B) = 0.1, P(C) = 0.2, P(D) = 0.3 The average number of bits per letter is

- 0 bit
- 1 bit
- 0 bit
- 9 bit

Correct option is C

- Which of the following is not a part of the channel coding?
- rectangular code
- Checksum checking
- Hamming code
- Huffman code

Correct option is D

- Which of the following is the first phase of JPEG?
- DCT Transformation
- Quantization
- Data Compression
- None of the above

Correct option is D

- Which type of method is used is used to compress data made up of combination of symbols?
- Run- length encoding
- Huffman encoding
- Lempel Ziv encoding
- JPEG encoding

Correct option is A

- How many passes does lossy compression makes frequently?
- One pass
- Two pass
- Three pass
- Four pass

Correct option is B

- Information is the
- data
- meaningful data
- raw data
- Both A and B

Correct option is B

**Unit-III**

- In dictionary techniques for data compaction, which approach of building dictionary is used for the prior knowledge of probability of the frequently occurring patterns?

- Adaptive dictionary
- Static dictionary
- Both
- None of the above

Correct option is B

- If the probability of encountering a pattern from the dictionary is p, then the average number of bits per pattern R is given by

- R=21-12p
- R=9-p
- R=21-p
- R=12-p

Correct option is A

- Static dictionary –

- permanent
- sometimes allowing the addition of strings but no deletions
- allowing for additions and deletions of strings as new input symbols are being read
- Both (A) and (B)
- Both (A) and (C)

Correct option is D

- Adaptive dictionary –

- holding strings previously found in the input stream
- sometimes allowing the addition of strings but no deletions
- allowing for additions and deletions of strings as new input symbols are being read
- Both (A) and (B)
- Both (A) and (C)

Correct option is E

- LZ77 and LZ78 are the two

- Lossy data compression
- Lossless data compression
- Both
- None of the above

Correct option is B

- Deflate =………….

- LZ78 + Huffman
- LZ77 + Huffman
- LZW + Huffman
- None of these

Correct option is B

- Full form of GIF

- Graphics Interchange Form
- Graphics Inter Format
- Graphics Interchange Format
- Graphics Interact Format

Correct option is C

- LZ78 has

- fast, slow
- slow, fast
- None of these

Correct option is B

- Compression packages which use an LZ77-based algorithm followed by a variable-length coder.

- PKZip
- Zip
- PNG
- All of the above

Correct option is D

- Application of LZW

- GIF
- Zip
- PNG
- All of the above

Correct option is A

- Algorithm used for solving temporal probabilistic reasoning

- Depth-first search
- Hidden markov model
- Hidden markov model
- Breadth-first search

Correct option is C

- Where does the Hidden Markov Model is used?

- Understanding of real world
- Speech recognition
- Both
- None of the above

Correct option is B

- A coding scheme that takes advantage of long runs of identical symbols is called as

- Move-to-front coding
- Binary coding
- Huffman coding
- Move-to-back coding

Correct option is A

- The idea with wavelets is to represent a complicated function by
- simple basic functions
- sinus functions
- lines
- square functions

Correct option is A

- In a typical picture, most pixels will be
- equal
- very different to their neighbors
- bright
- very similar to their neighbors

Correct option is C

- Without losing quality, JPEG-2000 can achieve compression ratios of

- 2:1
- 200:1
- 2000:1
- 20:1

Correct option is B

- The best visual compression quality is achieved using
- Fourier transform
- Wavelets
- DCT
- Dolby

Correct option is B

- Which is the image processing technique used to improve the quality of image for human viewing?
- compression
- enhancement
- restoration
- analysis

Correct option is B

- To remove archival compression and restore the data to column store compression
- Use ALTER TABLE
- Use ALTER COLUMN
- Use ALTER DATABASE
- All of the mentioned

Correct option is A

- Point out the wrong
- You can enable or disable ROW or PAGE compression in online state only
- When you are compressing indexes, leaf-level pages can be compressed with both row and page compression
- Non–leaf-level pages do not receive page compression
- None of the mentioned

Correct option is A

- What is image?
- Picture
- Matrix of pixel
- Collection of pixel
- All of these

Correct option is D

- An image transmitted using wireless network:
- corrupted as a result of lighting or other atmospheric
- non-corrupted as a result of lighting or other atmospheric
- corrupted as a result of pixel
- none of above

Correct option is A

**Unit-IV**

- Which of the following characterizes a quantizer

- Quantization results in a non-reversible loss of information
- A quantizer always produces uncorrelated output samples
- The output of a quantizer has the same entropy rate as the input
- None of the above

Correct option is A

- What is the signal-to-noise ratio (SNR)?

- The ratio of the average squared value of the source output and the squared error of the source output
- The ratio of the average squared value of the source output and the mean squared error of the source output
- The ratio of the average squared value of the source output and the absolute difference measure of the source output
- None of the above

Correct option is B

- The output signal of a scalar quantizer has property

- The output is a discrete signal with a finite symbol alphabet
- The output is a discrete signal with a countable symbol alphabet (but not necessarily a finite symbol alphabet)
- The output signal may be discrete or continuous
- None of the above

Correct option is B

- What is a Lloyd quantizer?

- For a given source, the Lloyd quantizer is the best possible scalar quantizer in ratedistortion That means, there does not exist any other scalar quantizer that yields a smaller distortion at the same rate.
- The output of a Lloyd quantizer is a discrete signal with a uniform pmf
- Both (A) and (B)
- A Lloyd quantizer is the scalar quantizer that yields the minimum distortion for a given source and a given number of quantization

Correct option is D

- Which of the following statement is correct for comparing scalar quantization and vector quantization?

- Vector quantization improves the performance only for sources with memory. For iid sources, the best scalar quantizer has the same efficiency as the best vector quantizer
- Vector quantization does not improve the rate-distortion performance relative to scalar quantization, but it has a lower complexity
- By vector quantization we can always improve the rate-distortion performance relative to the best scalar quantizer
- All of the above

Correct option is C

- If {x}
_{n}is the source output and {y}_{n}is the reconstructed sequence, then the squared error measure is given by

- d(x, y) = (y – x)
^{2} - d(x, y) = (x – y)
^{2} - d(x, y) = (y + x)
^{2} - d(x, y) = (x – y)
^{4}

Correct option is B

- If {x}
_{n}is the source output and {y}_{n}is the reconstructed sequence, then the absolute difference measure is given by

- d(x, y) = |y – x|
- d(x, y) = |x – y|
- d(x, y) = |y + x|
- d(x, y) = |x – y|
^{2}

Correct option is B

- The process of representing a

- Large, smaller
- Smaller, large
- None of these

Correct option is A

- The set of inputs and outputs of a quantizer can be

- Only scalars
- Only vectors
- Scalars or vectors
- None of these

Correct option is C

- Which of the folowing is/are correct for uniform quantizer

- The simplest type of quantizer is the uniform quantizer
- All intervals are the same size in the uniform quantizer, except possibly for the two outer intervals
- The decision boundaries are spaced evenly
- All of the above

Correct option is D

- If a Zero is assigned a decision level, then what is the type of quantizer?

- A midtread quantizer
- A midrise quantizer
- A midtreat quantizer
- None of the above

Correct option is B

- If a Zero is assigned a quantization level, then what is the type of quantizer?

- A midtread quantizer
- A midrise quantizer
- A midtreat quantizer
- None of the above

Correct option is A

- The main approaches to adapting the quantizer parameters:

- An off-line or forward adaptive approach
- An on-line or backward adaptive approach
- Both
- None of the above

Correct option is C

- Uniform quantizer is also called as

- Low rise quantizer
- High rise quantizer
- Mid rise quantizer
- None of the above

Correct option is C

- Non uniform quantizer

- Decrease
- Increase
- Doesn’t change
- None of the above

Correct option is A

- The spectral density of white noise is

- Poisson
- Exponential
- Uniform
- Gaussian

Correct option is C

- Which audio/video refers to on-demand requests for compressed audio/video files?
- Streaming live
- Streaming stored
- Interactive
- None of the above

Correct option is B

- According to Nyquist theorem, how many times the highest frequency we need to sample an analog signal?
- Three
- Two
- Four
- None of the above

Correct option is B

- Which encoding is based on the science of psychoacoustics, which is the study of how people perceive sound?

- Predictive
- Perceptual
- Both of the above
- None of the above

Correct option is B

- SDH uses to measure block errors.
- CRC
- Rectangular code
- bit-interleaved parity (BIP )
- Simple parity check

- The minimum sampling rate is called?
- Data rate
- symbol rate
- Nyquist rate
- None of the above

Correct option is C

- Spread spectrum is used for
- Encrypting signal
- Hiding signal
- Encrypting & Hiding signal
- None of the mentioned

Correct option is C

- Which is a quantization process?
- Rounding
- Truncation
- Rounding & Truncation
- None of the mentioned

Correct option is C

- . Quantization is a……………..process.
- Non linear
- Reversible
- Non linear & Reversible
- None of the mentioned

Correct option is C

- The mutual information between a pair of events is
- Positive
- Negative
- Zero
- All of the mentioned

Correct option is D

- The SNR value can be increased by

- Increasing
- Decreasing
- Does not depend on
- None of the mentioned

Correct option is A

- 1 bit quantizer is a
- Hard limiter
- Two level comparator
- Hard limiter & Two level comparator
- None of the mentioned

Correct option is C

- The low pass filter at the output end of delta modulator depends on
- Step size
- Quantization noise
- Bandwidth
- None of the mentioned

Correct option is C

- Quantization Matrix in JPEG compression was introduced because
- It is computationally more efficient to work with matrix than with scalar quantization;
- It allows better entropy encoding due to DC and AC coefficient distribution in the 8×8 block matrix;
- It allows better differentiation of DC and AC coefficients in the 8×8 block matrix than a scalar quantization;

Correct option is C

- What property has the output signal of a scalar quantizer
- The output is a discrete signal with a countable symbol alphabet (but not necessarily a finite symbol alphabet).
- The output is a discrete signal with a finite symbol
- The output signal may be discrete or continuous

Correct option is A

**Unit-V**

- Characteristic of a vector quantizer

- Multiple quantization indexes are represented by one codeword
- Each input symbol is represented by a fixed-length codeword
- Multiple input symbols are represented by one quantization index
- All of the above

Correct option is C

- Vector quantization is rarely used in practical applications, why?

- The coding efficiency is the same as for scalar quantization
- The computational complexity, in particular for the encoding, is much higher than in scalar quantization and a large codebook needs to be stored
- It requires block Huffman coding of quantization indexes, which is very complex
- All of the above

Correct option is B

- Let N represent the dimension of a vector quantizer. What statement about the performance of the best vector quantizer with dimension N is correct?

- For N approaching infinity, the quantizer performance asymptotically approaches the rate- distortion function (theoretical limit)
- By doubling the dimension N, the bit rate for the same distortion is halved
- The vector quantizer performance is independent of N
- All of the above

Correct option is A

- Which of the following is/are correct for the advantage of vector quantization over scalar quantization.

- Vector Quantization can lower the average distortion with the number of reconstruction levels held constant
- Vector Quantization can reduce the number of reconstruction levels when distortion is held constant
- Vector Quantization is also more effective than Scalar Quantization When the source output values are not correlated
- All of the above

Correct option is D

- Vector quantization is used for

- Lossy data compression
- Lossy data correction
- Pattern recognition
- All of the above

Correct option is D

- The Linde–Buzo–Gray algorithm is a

- Scalar
- Vector
- Both
- None of the above

Correct option is B

- Vector quantization is used in

- Video coding
- Audio coding
- Speech coding
- All of the above

Correct option is C

- What are processes (Techniques) used in video coding?

- Partition of frames into macroblocks
- Form of Vector Quantization
- Both (A) & (B)
- None of these

Correct option is C

- The process of converting the analog sample into discrete form is called

- Modulation
- Multiplexing
- Quantization
- Sampling

Correct option is C

10 . The sequence of operations in which PCM is done is

- Sampling, quantizing, encoding
- Quantizing, encoding, sampling
- Quantizing, sampling, encoding
- None of the above

Correct option is A

- To convert a continuous sensed data into Digital form, which of the following is required?
- Sampling
- Quantization
- Both Sampling and Quantization
- Neither Sampling nor Quantization

Correct option is C

- For a continuous image f(x, y), Quantization is defined as
- Digitizing the coordinate values
- Digitizing the amplitude values
- All of the mentioned
- None of the mentioned

Correct option is B

- The resulting image of sampling and quantization is considered a matrix of real numbers. By what name(s) the element of this matrix array is called

- Image element or Picture element
- Pixel or Pel
- All of the mentioned
- None of the mentioned

Correct option is C

- Which conveys more information?
- High probability event
- Low probability event
- High & Low probability event
- None of the mentioned

Correct option is B

- The probability density function of the envelope of narrow band noise is
- Uniform
- Gaussian
- Rayleigh
- Rician

Correct option is B

- Which model is known as ignorance model?
- Physical model
- Markov model
- Probability model
- Composite Source Model

Correct option is C

- Shannons theorem is also called
- noiseless coding theorem
- noisy coding theorem
- coding theorem
- noiseless theorem Answer

Correct option is A

- Transform coding, vector quantization are examples for
- Pixel
- compression
- Transmission
- Lossy compression Answer

Correct option is D

19. Entropy Coding is an __ __

- Lossless
- Lossy
- 0
- None

Correct option is A

20. __ __is normally used for the data generated by scanning the documents, fax machine, typewriters etc.

- Huffman Coding
- Transformation Coding
- Vector Quantization
- Runlength Encoding

Correct option is D

21. Compression Technique used in Image Video is

- Huffman Coding
- Transformation Coding
- Entropy Coding
- Differential Encoding

Correct option is B

22. Compression Technique used in Audio is

- Differential Encoding
- Transformation Encoding
- Entropy Coding
- Differential & Transformation Encoding

correct option is D

23. Expansion of LZ Coding is

- Lossy
- Lossless
- Lempel-ziv-welsh
- Lempel-ziv

Correct option is D

24. Expansion of LZW Coding is

- Lossy
- Lossles
- Lempel-ziv
- Lempel-ziv-welsh

Correct option is D