# Combined Linear and Constant Envelope Modulation Techniques

This set of Wireless & Mobile Communications Quiz focuses on “Combined Linear and Constant Envelope Modulation Techniques”.

1. Which of the following is a combined linear and constant envelope technique?
a) MPSK
b) PSK
c) BPSK
d) QPSK

2. In an M-ary signalling scheme two or more bits are grouped together to form a _______
a) Chip
b) Symbol
c) Byte
d) Pattern

3. The number of possible signal in M-ary signalling is given by M and M = __________ where n is an integer.
a) n
b) 2n
c) 2n
d) n2

4. M-ary signalling techniques are not sensitive to timing jitters.
a) True
b) False

5. M-ary modulation schemes have very good power efficiency.
a) True
b) False

6. In M-ary PSK, the carrier ___________ takes one of M possible values.
a) Amplitude
b) Frequency
c) Angle
d) Phase

7. The constellation of M-ary PSK is ____________ dimensional.
a) One
b) Does not exist
c) Two
d) Three

8. What is the radius of the circle in M-ary PSK on which message points are equaly spaced?
a) √Es
b) √Eb
c) Eb
d) Es

9. As the value of M _________ the bandwidth efficiency ________
a) Increases, same.
b) Increases, decreases
c) Increases, increases
d) Decreases, same

10. The power efficiency of the M ary PSK decreases because of the _____
a) Freely packed constellation
b) Increment of bandwidth efficiency
c) Fixed null bandwidth
d) Densely packed constellation

11. In QAM, the amplitude is _______ and phase is _______
a) Varied, constant
b) Varied, varied
c) Constant, varied
d) Constant, constant

12. M-ary QAM signal have constant energy per symbol.
a) True
b) False

13. In comparison to M-ary PSK, M-ary QAM bandwidth efficiency is _____ and power efficiency is ________
a) Identical, superior
b) Less, superior
c) Identical, identical
d) Superior, superior

14. The bandwidth efficiency of an M-ary FSK signal ________ with ________ in M.
a) Constant, increase
b) Increases, increase
c) Decreases, increase
d) Decreases, decrease

15. Power efficiency of M-ary FSK increases, since _________
a) Constellation is densely packed
b) M signals are non-orthogonal
c) Fixed null bandwidth
d) M-signals are orthogonal