WCM - Chpt2

Q1) Define the following terms:

• Frequency

• The speed at which a wave travels through a medium

• The distance between two consecutive peaks of a wave

• The maximum height of a wave from its rest position.

• Frequency of a signal is the number of complete cycles per second.

Define the following terms: Wavelength

• The number of cycles of a wave that pass a fixed point in one second.

• The distance travelled by a wave during the time of one cycle

• The speed at which a wave travels through a medium.

• The maximum height of a wave from its rest position

Define the following terms: Period

• The number of cycles of a wave that pass a fixed point in one second.

• The maximum height of a wave from its rest position.

• Period of a signal is the time taken to complete one cycle.

• The distance between two consecutive peaks of a wave.

The wavelength of a radio frequency signal is 3m. Determine its:

•Frequency

•Period

• f = 100MHz
  T = 0.01μs

• f = 10MHz
  T = 0.01μs

• f = 100MHz
  T = 0.1μs

• f = 100KHz
  T = 0.01μs

A radio signal has a frequency of 88MHz. Determine its

(a) Wavelength

(b) Period

• λ = 3.48m
  T = 11.8ns

• λ = 3.41m
  T = 11.4ns

• λ = 3.41m
  T = 11.4μs

• λ = 3.41n
  T = 11.4μs

State four common types of ‘Line Encoding’

• Amplitude Modulation, Frequency Modulation, Phase Modulation, Pulse Width Modulation

• Time Division Multiplexing (TDM), Frequency Division Multiplexing (FDM), Code Division Multiplexing (CDM), Space Division Multiplexing (SDM)

• Pulse Amplitude Modulation (PAM), Quadrature Amplitude Modulation (QAM), Frequency Shift Keying (FSK), Phase Shift Keying (PSK)

• Unipolar Encoding, Polar Encoding, Bipolar Encoding, Manchester Encoding

Define ‘Baud Rate’

• The maximum number of bits transmitted per second.

• The number of signal units per second that are required to represent those bits.

• The number of cycles of a wave that pass a fixed point in one second.

• The time it takes for one complete cycle of a wave to pass a fixed point.

An Analogue Signals carries 8 bits in each signal element. If 1000 signal elements are sent per second, determine its ‘Baud Rate’ and ‘Bit Rate’.

• Baud Rate = 1000 bauds per second
  
  Bit Rate = 8000bps

• Baud Rate = 10000 bauds per second
  
  Bit Rate = 80000bps

• Baud Rate = 100 bauds per second
  
  Bit Rate = 800bps

• Baud Rate = 10 bauds per second
  
  Bit Rate = 80bps

The ‘Bit Rate’ of a signal is 2000bps. If 500 signal elements are sent per second, calculate the number of bits in each signal element.

• Number of Bits per Signal Element= 4 bits

• Number of Bits per Signal Element= 8 bits

• Number of Bits per Signal Element= 16 bits

• Number of Bits per Signal Element= 32 bits

 Determine the ‘Baud Rate’ of a data communication network that has a data transmission rate of 64kbps with each signal element carrying 8 bits.

• Baud rate = 32k baud per sec

• Baud rate = 4k baud per sec

• Baud rate = 8k baud per sec

• Baud rate = 16k baud per sec