Ch 2
All forms of electromagnetic energy travel through space in the form of particles.
False
Hopping codes used in FHSS transmissions are configured on the base station by the network administrator.
False
Infrared light is highly susceptible to interference from other sources of light.
False
Spread-spectrum signals are more susceptible to outside interference than narrow-band transmissions.
False
a technique that changes the number of wave cycles in response to a change in the amplitude of the input signal
Frequency Modulation
the sequence of changing frequencies used in FHSS
Hopping Code
What is the unit of measurement for radio frequency?
Hz
Which of the following is NOT a limitation of using infrared wireless systems?
someone can easily eavesdrop from another room
What process must occur to transmit a digital signal over an analog medium?
modulation
What is the distance between a point in one wave cycle and the same point in the next wave cycle?
wavelength
Which type of radio signal is most susceptible from interference sources such as lightning?
AM
an arbitrary coding scheme that uses the numbers from 0 to 127 to represent alphanumeric characters and symbols
ASCII
Which binary modulation technique employs NRZ coding such that the absence of a carrier signal represents a 0 bit?
ASK
a technique that changes the height of a carrier wave in response to a change in the height of the input signal
Amplitude Modulation
What type of signal is broadcast as a continuous wave?
Analog
a signal in which the intensity varies continuously and smoothly over a period of time
Analog Signal
the number of times that a carrier signal changes per second
Baud Rate
an analog wave having a frequency that a receiver is tuned to
Carrier Wave
A wave that is composed of one top and one bottom peak has completed which of the following?
Cycle
Which radio transmission method uses a chipping code?
DSSS
a method of encoding a digital signal onto an analog carrier wave
Digital Modulation
a binary signaling technique that increases the voltage to represent a 1 bit but provides no voltage for a 0 bit
NRZ
a technique that changes the starting point of a wave cycle in response to a change in the amplitude of the input signal
PM
Which non-return-to-zero encoding method represents a 1 bit by increasing voltage to a positive value and a 0 bit by decreasing the voltage to a negative value?
Polar
In PSK, what is the technique of combining amplitude and phase modulation called?
QAM
Which binary signaling technique reduces the voltage to zero before the end of the period for transmitting a 1 bit?
RZ
The height of a radio wave is called the amplitude of the wave.
True
Which of the following is NOT true about infrared light?
all infrared signals are invisible
Which of the following is NOT a type of modulation that can be applied to an analog signal?
carrier
Which of the following is true about baud rate?
multiple bits can be transferred with each signal unit
Which of the following is a good application for an infrared wireless system?
data transfer between laptop and camera
Which of the following is a spread spectrum technique that employs mathematical algorithms to recover lost data bits?
direct sequence
What do data signals on a wireless communication system travel on?
electromagnetic waves
Which of the following transmits a signal in an infrared device?
emitter
Which best describes an analog audio signal?
intensity varies and is continuous
What is the role of an antenna on a wireless device?
it transmits and receives data
Which of the following is NOT an advantage of digital modulation over analog modulation?
less sophisticated
The frequency of a wave is best defined as which of the following?
the number of times a cycle occurs each second
Which of the following best describes bandwidth in an analog system?
the range of frequencies that can be transmitted by a system
Which of the following is true about wireless radio signal transmissions?
they travel at the speed of light
