Tomasi Chapter 11

Question 1

Combining multiple signals on one channel.

Answer 1

Multiplexing

Question 2

Time is divided into slots; each signal gets a slot.

Answer 2

TDM (Time Division Multiplexing)

Question 3

24 PCM channels, 8-bit samples, 1.544 Mbps.

Answer 3

T1 System

Question 4

Carries supervisory info (on/off-hook, ring).

Answer 4

Signaling Bit

Question 5

Identifies time-slot boundaries; done with special framing bits.

Answer 5

Frame Sync

Question 6

12 T1 frames grouped for better sync and signaling.

Answer 6

Superframe

Question 7

A/D + D/A.

Answer 7

Codec

Question 8

codec + filters in one IC.

Answer 8

Combo Chip

Question 9

Constant transmission rate.

Answer 9

Fixed Data Rate

Question 10

Rate changes with activity.

Answer 10

Variable Data Rate

Question 11

Digital cross-connect panel for testing and routing.

Answer 11

DSX

Question 12

Mapping bits into a waveform for transmission.

Answer 12

Line Coding

Question 13

one polarity.

Answer 13

Unipolar

Question 14

alternating polarities

Answer 14

bipolar

Question 15

returns to zero each bit

Answer 15

RZ

Question 16

Stays level

Answer 16

NRZ

Question 17

RZ requires ____ bandwidth

Answer 17

more

Question 18

NRZ requires ____ bandwidth

Answer 18

less

Question 19

RZ has _____ clock recovery

Answer 19

easier

Question 20

NRZ has ______ clock recovery

Answer 20

harder

Question 21

Retimes, reshapes, and amplifies digital signals.

Answer 21

Regenerative Repeater

Question 22

Zero-substitution codes

Answer 22

B6ZS / B3ZS

Question 23

uses T1 for substitution

Answer 23

B6ZS

Question 24

uses higher rates for substitution

Answer 24

B3ZS

Question 25

Framing Types

Answer 25

Added-digit, robbed-digit, added-channel, statistical, unique-code.

Question 26

1 bit per channel

Answer 26

bit

Question 27

full PCM words per channel

Answer 27

Word Interleaving

Question 28

Each signal uses a different frequency band.

Answer 28

FDM (Frequency Deviation Multiplexing)

Question 29

One modulated voice/data slot in FDM.

Answer 29

Message Channel

Question 30

12 channels

Answer 30

group

Question 31

5 groups

Answer 31

super group

Question 32

10 super groups

Answer 32

master group

Question 33

original signal

Answer 33

baseband

Question 34

multiplexed baseband

Answer 34

composite baseband

Question 35

Frequency gap to prevent interference.

Answer 35

Gard Band

Question 36

Multiple wavelengths (colors) in one fiber.

Answer 36

WDM (wave division multiplexing)

Question 37

has denser spacing and more channels compared to WDM

Answer 37

DWDM (Dense Wavelength Division Multiplexing)

Question 38

WDM Components

Answer 38

MUX/DEMUX, add/drop MUX, wavelength router.

Question 39

Fused fiber, planar waveguide, grating-based.

Answer 39

Wavelength Couplers

Question 40

Also called an Optical Standard

Answer 40

Sonet

Question 41

OC 1 = ____ Mbps

Answer 41

51.84 Mbps

Question 42

OC 48 = ___ Gbps

Answer 42

2.488 Gbps