comms

Question 1

DIGITAL

Answer 1

root term digit which came from the latin word “digitus” which means fingers/toes.

Question 2

COMMUNICATION

Answer 2

came from the word “communis”(n) which means common and “communicare” (v) which mean to share.

Question 3

DIGITAL COMMUNICATION

Answer 3

Process of sharing of digital information

Question 4

LTE-

Answer 4

Long Term Evolution (4G)

Question 5

EDGE-

Answer 5

Enhanced Data for Global Evolution (2.75G)

Question 6

ERP –

Answer 6

Effective Radiated Power

Question 7

HARTLEY’S LAW
For noiseless condition:

Answer 7

C=kB∙T

Question 8

HARTLEY’S LAW
For noisy condition:

Answer 8

C=B 〖log〗_2⁡(1+S/N)

Question 9

M-ARY ENCODING

Answer 9

N=〖log〗_2⁡(M)

Question 10

BAUD

Answer 10

B=f_b/N

Question 11

(bit rate) f_b

Answer 11

f_b=2B
f_b=2B 〖log〗_2⁡M

Question 12

AMPLITUDE MODULATION KEYING (ASK)

Answer 12

V_ASK (t)=[1+V_m (t)][A/2 cosω_c t]

Question 13

CARRIER CENTER FREQUENCY

Answer 13

f_c=ω_c/2π

Question 14

MODULATION INDEX

Answer 14

M.I.=(V_max-V_min)/(V_max-V_min )

Question 15

FREQUENCY MODULATION KEYING (FSK)

Answer 15

V_FSK (t)=V_c cos{2π[f_c+V_m (t)∙∆f]t}

Question 16

FREQUENCY DEVIATION

Answer 16

∆f=|f_m-f_s |/2

Or
(ONLY IN OPTIMAL STATE) ∆f=f_b/2

Question 17

TOTAL BANDWIDTH

Answer 17

BW=2(∆f+f_b )

Question 18

MODULATION INDEX in FSK

Answer 18

M.I.=∆f/(f_b/ f_a )
Or
M.I.=|f_m-f_s |/f_b

Question 19

MARK FREQUENCY

Answer 19

f_m= f_c+f_b

Question 20

SPACE FREQUENCY

Answer 20

f_s= f_c-f_b

Question 21

MAXIMUM FREQUENCY

Answer 21

f_max= f_m+f_b

Question 22

MINIMUNM FREQUENCY

Answer 22

f_min= f_s-f_b

Question 23

PHASE SHIFT KEYING

Answer 23

v (t)=V sin{2π*ft+θ}

Question 24

BANDWIDTH IN PSK

Answer 24

BW=f_b
Or
BW=〖(f〗_c+f_a)-〖(f〗_c-f_a)
BW=2f_a

Question 25

Retransmission (ARQ)

Answer 25

• When a receive station request the transmit station to resend a message

Question 26

Forward Error Correction

Answer 26

• Error-correction scheme that actually detects and corrects transmission errors.

Question 27

HAMMING CODE

Answer 27

• Richard W. Hamming
• For error-detection and correction of sync data streams
• Will correct only single-bit errors

2^n≥(m+n)+1

Question 28

PULSE MODULATION

Answer 28

• The most common modulation technique used for analog to digital conversion

Question 29

PULSE WIDTH MODULATION

Question 30

PULSE POSITION MODULATION (PPM)

Question 31

PULSE AMPLITUDE MODULATION (PAM)

Question 32

PULSE CODE MODULATION PCM)

Question 33

PARALLEL TRANSMISSION

Answer 33

• Parallel transmission is the mode of transmitting group of n bits at a single time instead of only 1

Question 34

SERIAL TRANSMISSION

Answer 34

• One bit follows another, so we need only one communication channel rather than n to transmit data between two

Question 35

Most common sampling method

Answer 35

• Sample and hold circuit

Question 36

TYPES OF SAMPLING

Answer 36

• IDEAL (IMPULSE)
• NATURAL
• FLAT-TOP