Est. Wire And Wireless Communication

Front 1

The velocity factor of a transmission line

Back 1

depends on the dielectric constant of the material used

Front 2

Impedance inversion may be obtained with

Back 2

a quarter-wave line

Front 3

For transmission-line load matching over a range of frequencies, it is best to use a

Back 3

double stub

Front 4

The main disadvantage of the two-hole directional coupler is

Back 4

narrow bandwidth

Front 5

To couple a coaxial line to a parallel-wire line, it is best to use a

Back 5

Balun

Front 6

Indicate the three types of transmission line energy losses.

Back 6

Radiation, I2R, and dielectric heating

Front 7

Indicate the true statement below. The directional coupler is

Back 7

a coupling device for matching impedance

Front 8

An ungrounded antenna near the ground

Back 8

acts as a single antenna of twice the height

Front 9

Full-duplex transmission means

Back 9

Two-way simultaneous transmission

Front 10

A passive _________ is an electronic device which reduces signal strength by a specified amount in dB.

Back 10

Attenuator

Front 11

The signal quality of the calls is constantly monitored by the base station, when the quality of the calls drops below a certain specified level. The base request the MTSO to try and find a better cell site.

Back 11

Roaming

Front 12

A digital identification associated with a cellular system.

Back 12

MIN

Front 13

Cause a herringbone pattern in facsimile

Back 13

Crosstalk

Front 14

A device that converts a 2-wire circuit to a 4-wire circuit.

Back 14

Hybrid circuit

Front 15

______ of a data reduction says that when reducing a set of data into the form of an underlying mode, one should be maximally non-committal with respect to missing data.

Back 15

Jaynes maximum entropy principle

Front 16

Combination of madulator, channel, and detector.

Back 16

Discrete channel

Front 17

How many simultaneous calls does each DECT system can support?

Back 17

12

Front 18

If you find that an SAW filter output is 6 dB down from the input of a receiver during test, ______

Back 18

This is normal.

Front 19

What is a leased line?

Back 19

A permanent circuit for a private use within a communication network

Front 20

What is the number of channels of a cellular system with an allocated spectrum of 25 MHz and with a channel of 30 kHz bandwidth?

Back 20

833

Front 21

GSM uses what digital modulation technique?

Back 21

GMSK

Front 22

What is the power output of Personal Communication System (PCS)?

Back 22

10 mW

Front 23

The signals designed to keep the receivers and transmitters aligned.

Back 23

Pilot carrier signals

Front 24

If the spacing of a two-wire open air transmission line is 12 inches and the conductor diameter is 0.25 inch, the characteristic impedance is

Back 24

547 Ω

Front 25

The impedance of the quarterwave transformer used to match a 600 Ω line to a 300 Ω load is

Back 25

424 Ω

Front 26

When a line and a load are match the reflection coefficient is

Back 26

Zero

Front 27

When line is terminated in an open circuit load, the reflection coefficient is

Back 27

Unity

Front 28

A 300 ohms line is terminated in a resistance load of 200 ohms, the VSWR is

Back 28

1.5

Front 29

If the reflection coefficient is 0.5, the standing wave ratio is

Back 29

3

Front 30

To least the fault of the given line, a signal is fed to the line, 30 µs later the signal returned. What is the distance of the fault?

Back 30

4500 m

Front 31

The telephone set is powered by the central office on the ring side at

Back 31

– 42 to -52 Vdc

Front 32

The physical connection between the telephone set and the switching equipment is called the

Back 32

Subscriber loop

Front 33

A cell in the cellular telephone system means

Back 33

Small area

Front 34

What is the typical power output of a cellular phone?

Back 34

3W

Front 35

The number of transmit/receive channels in the cellular system is

Back 35

666

Front 36

When the message is transferred from one cell site transmitter to another cell site transmitter as the caller crosses a boundary __________ process takes place.

Back 36

Hand off

Front 37

What is the frequency deviation of the cellular telephone system?

Back 37

±12 kHz

Front 38

What type of connector arrangement wherein a customer may move to another location and still retain the same telephone number.

Back 38

TPS

Front 39

The transmission of information from multiple sources occurring on the same facility but not as the same time.

Back 39

TDM

Front 40

Termination refers to

Back 40

Load connected to the output end of a transmission line

Front 41

Under ordinary circumstances, the CCITT recommends that the number of circuits in tandem must not exceed

Back 41

12

Front 42

The GSM cellular radio system uses GMSK in a 200-kHz, with a channel data rate of 270.833 kbps. Calculate the frequency shift between mark and space in kHz?

Back 42

135.4165

Front 43

A multiple access technique used in GSM cellular system.

Back 43

TDMA

Front 44

The central office detects a request for service from a telephone by

Back 44

A flow of loop current

Front 45

What type of transmitter is most commonly used in a conventional telephone handset?

Back 45

Carbon

Front 46

In digital multiplexing systems, bit interleaving is used in

Back 46

Higher level systems

Front 47

A technique that divides the group of channels into smaller groupings or segments of mutually exclusive frequencies; cell sites, which are within the reuse distance is assigned their own segment of the channel group

Back 47

Segmentation

Front 48

In a spread spectrum system, the tendency for a stronger signals to interfere with the reception of weaker signals.

Back 48

near-far effect

Front 49

Technique used in spread spectrum that adds a high-bit rate pseudorandom code to a low bit rate information signal to generate a high-bit rate pseudorandom signal closely resembling noise that contains both the original data signal and pseudorandom noise.

Back 49

direct-sequence

Front 50

Circular waveguides use TM01 mode because:

Back 50

of its circular symmetry