# Waveform Coding

This set of Digital Communications Multiple Choice Questions & Answers (MCQs) focuses on “Waveform Coding”.

1. Channel coding relates to area such as

a) Waveform coding

b) Structured sequence**c) Waveform coding & Structured sequence**

d) None of the mentioned

2. Examples of structured sequences are

a) Block codes

b) Convolutional codes

c) Turbo codes**d) All of the mentioned**

3. Antipodal signals are

a) Mirror images

b) 1800 apart

c) One is negative of the other**d) All of the mentioned**

4. Orthogonal vectors are

a) Perpendicular to each other

b) Their dot product must be zero

c) One signal cannot interfere with the other**d) All of the mentioned**

5. In orthogonal signalling as k increase there is**a) Improved error performance**

b) Degraded error performance

c) Improved bandwidth

d) None of the mentioned

6. In non orthogonal signalling as k increases there is

a) Degraded error performance

b) Improved bandwidth efficiency

c) Increase in required Eb/N0**d) All of the mentioned**

7. In orthogonal signal, all cross correlation coefficients are

a) One**b) Zero**

c) Negative

d) None of the mentioned

8. The smaller the cross correlation, the ______ is the distance between the signal vectors.**a) More**

b) Less

c) Double

d) Half

9. Hadamard matrix is given as

a)

H2 = H1 H1 H1 H1

b)

H2 = H1 H1 H1'H1

**c)**

H2 = H1 H1 H1 H1'

d)

H2 = H1'H1 H1 H1

10. Biorthogonal set consists of

a) Orthogonal signals

b) Antipodal signals**c) Combination of orthogonal and antipodal**

d) None of the mentioned

11. Which codes perform better?

a) Orthogonal**b) Biorthogonal**

c) Orthogonal & Biorthogonal

d) None of the mentioned

12. Biorthogonal codes needs ________ bandwidth as orthogonal codes.

a) Equal

b) Double**c) Half**

d) Triple

13. Transorthogonal code is obtained by

a) Deleting last digit of each orthogonal codeword**b) Deleting first digit of each orthogonal codeword**

c) Doubling each digit of orthogonal codeword

d) Taking negative of each digit of orthogonal codeword

14. Which code requires minimum Eb/N0?

a) Orthogonal

b) Biorthogonal**c) Simplex**

d) All of the mentioned