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Flashcards in Psk Deck (17)
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1
Q

What is the definition of phase modulation ?

A

A carrier wave is phase modulated when its phase is changed in sympathy with the amplitude of the modulating wave.

2
Q

What is phase deviation ?

A

The amount of phase change produced by the modulating wave is called phase deviation.

3
Q

What’s is phase modulation not used in ?

A

Practical analogue transmission systems such as speech and music

4
Q

What is the carrier frequency?

A

The frequency occupied by the carrier in its unmodulated state

5
Q

What is phase deviation ?

A

Maximum amount of phase change produced by the maximum modulating wave amplitude.

6
Q

What is phase shift keying ? (Psk)

A

A special case of phase modulation in which the carrier phase is shifted between discreet phase values.

7
Q

What is the minimum bandwidth equal to in psk?

A

The keying rate (Baud speed)

8
Q

Null to null bandwidth is equal to what ?

A

Modulation rate x2

9
Q

What significant difference does a psk have to a msk?

A

A drop of 13.7dB

10
Q

Which type of filtering is used with regards to satellite transmissions?

A

Side lobe filtering.

11
Q

How can we get rid of phase referencing ?

A

One moethod of countering phase referencing problems is to use an initial phase reference.

12
Q

What can we do to stop drift ?

A

To resend the reference more often. This takes time and is considered wasteful

13
Q

What is an amplitude ring ?

A

An imaginary circle drawn in a polar plot which denotes the clusters that share a common amplitude

14
Q

What is a signal state ?

A

The total number of amplitude land phase combinations a signal can attain

15
Q

What is a phase state ?

A

Data is represented by the phase of the signal in relation to a reference.

16
Q

What are the advantages of QAM?

A

Data rate and adaptability

17
Q

What is intial phase reference ?

A

Transmitting a known state at the beginning of the transmission and resending to keep in sync