COMMS

Question 1

_______is the process of exchanging information. Main barriers are language and distance.

Answer 1

Communication

Question 2

degrades or interferes with transmitted information.

Answer 2

Noise

Question 3

converts the electrical signal into a signal suitable for transmission over a given medium.

Answer 3

Transmitter

Question 4

made up of oscillators, amplifiers, tuned circuits and filters, modulators, frequency mixers, frequency synthesizers, and other circuit

Answer 4

Transmitter

Question 5

the electronic signal is
sent from one place to another.

Answer 5

Communication Channel

Question 6

accepts the transmitted message from the channel and converts it back into a form understandable by humans.

Answer 6

Receiver

Question 7

contain amplifiers, oscillators, mixers, tuned circuits and filters, and a demodulator or detector that “recovers the original intelligence signal from the modulated carrier”.

Answer 7

Receiver

Question 8

incorporates circuits that both send
and receive signals.

Answer 8

Transceiver

Question 9

Signal ____________, or degradation, exists in all media of wireless transmission. It is proportional to the square of the distance between the transmitter and receiver.

Answer 9

Attenuation

Question 10

is random, undesirable electronic energy that enters the
communication system via the communicating medium and “interferes with the transmitted message”.

Answer 10

Noise

Question 11

simplest method of electronic communication, “one way” communication

Answer 11

Simplex

Question 12

“two-way” communication, it is when people can talk and listen simultaneously

Answer 12

Full Duplex

Question 13

form of two-way communication in which “only one party transmits at a time”

Answer 13

Half Duplex

Question 14

is a smoothly and continuously varying voltage or current.

Answer 14

Analog Signal

Question 15

change in steps or in discrete increments

Answer 15

Digital Signals

Question 16

Most digital signals use __________ or ____________

Answer 16

binary or two-state codes.

Question 17

Many transmissions are of signals that originate in digital form but must be converted to analog form to match the transmission medium.

Answer 17

Digital Signals

Question 18

are electronic techniques for transmitting information efficiently from one place to another.

Answer 18

Modulation and Multiplexing

Question 19

makes the information signal more compatible with the medium.

Answer 19

Modulation

Question 20

allows more than one signal to be transmitted concurrently over a single medium.

Answer 20

Multiplexing

Question 21

can be “sent directly and unmodified” over the medium or can be used to modulate a carrier for transmission over the medium.

Answer 21

Baseband Transmission

Question 22

is a high frequency signal that is modulated by audio, video, or data.

Answer 22

carrier

Question 23

is an electromagnetic signal that is able to travel long distances through space.

Answer 23

radio-frequency (RF) wave or radio wave

Question 24

A _____________ takes place when a carrier signal is modulated, amplified, and sent to the antenna for transmission.

Answer 24

Broadband Transmission

Question 25

2 most common methods of modulation are:

Answer 25

1) Amplitude Modulation (AM) 2) Frequency Modulation (FM)

Question 26

phase angle of the sine wave is varied.

Answer 26

Phase Modulation (PM)

Question 27

takes place when data is converted to frequency-varying tones.

Answer 27

Frequency-shift keying (FSK)

Question 28

translate the data from digital to analog and back again.

Answer 28

Modems (modulator-demodulator)

Question 29

takes place in the receiver when the original baseband (e.g. audio) signal is extracted.

Answer 29

Demodulation or detection

Question 30

is the process of allowing two or more signals to share the same medium or channel.

Answer 30

Multiplexing

Question 31

3 basic types of multiplexing are:

Answer 31

1) Frequency division 2) Time division 3) Code division

Question 32

The range of electromagnetic signals encompassing all frequencies.

Answer 32

Electromagnetic Spectrum

Question 33

A ______ is located on the frequency spectrum according to its frequency and wavelength.

Answer 33

Signal

Question 34

A ________ consists of two voltage polarity reversals, current reversals, or electromagnetic field oscillations.

Answer 34

cycle

Question 35

is the number of cycles of a repetitive wave that occur in a given period of time.

Answer 35

Frequency

Question 36

Frequency is measured in _______

Answer 36

Cycles per second (cps)

Question 37

is the distance occupied by one cycle of a wave and is usually expressed in meters.

Answer 37

Wavelength

Question 38

is also the distance traveled by an electromagnetic wave during the time of one cycle.

Answer 38

Wavelength

Question 39

The wavelength of a signal is represented by the _________

Answer 39

Greek letter lambda (λ)

Question 40

exists directly above the millimeter wave region.

Answer 40

Optical Spectrum

Question 41

3 types of light waves are:

Answer 41

1) Infrared 2) Visible Spectrum 3) Ultraviolet

Question 42

is produced by any physical equipment that generates heat, including our bodies.

Answer 42

Infrared radiation

Question 43

Just above the infrared region is the ________ we refer to as "light".

Answer 43

visible spectrum

Question 44

___ is low-frequency or long-wavelength light

Answer 44

Red

Question 45

______ is high-frequency or short-wavelength light.

Answer 45

Violet

Question 46

____________ very high frequency "enables them to handle a tremendous amount of information" (the bandwidth of the baseband signals can be very wide).

Answer 46

Light waves

Question 47

is not used for communication, primary use is medical.

Answer 47

Ultraviolet

Question 48

is that portion of the electromagnetic spectrum occupied by a signal.

Answer 48

Bandwidth (BW)

Question 49

refers to the "range of frequencies required to transmit" the desired information.

Answer 49

Channel bandwidth