Question

QUESTION 1

1. A transmit signal operating at 100 watts suffers a 3dB signal reduction. What is the strength of your signal after suffering the 3dB hit?

		a. 97 watts
		b. 103 watts
		c. 50 watts
		d. 50 dB

QUESTION 2

1. Select the correct statement(s) regarding the Shannon Capacity Formula (C=B*log₂(1+SNR)).

		a. the Shannon Capacity formula identifies the theoretical maximum capacity achievable in any digital communications system
		b. the Shannon Capacity formula tells you that data rates will increase as signal bandwidth increases
		c. the Shannon Capacity formula tells you that data rates will increase as the signal-to-noise ratio increases.
		d. all of the above

QUESTION 3

1. Determine capacity (bits per second) using the Shannon Capacity Formula given the following parameters: Bandwidth=36MHz, [SNR](dB)=30 dB.  (hint: you must convert SNR in decibels to a non-decibel ratio)

		a. 36 Mbps
		b. 178 Mbps
		c. 359 Mbps
		d. 512 Mbps

Answer 1

Please find the answer for the above given quesitions.

ANSWERS :

For Question 1 )  

ANSWER : Option C , 50 watts

Formula for converting db's to watts is

Power in Db = 10* log(power in watts) Note : Log base 10 calculation , Not base 2

As per the above given formula 100 watts is equal to 20db

So 20 db reduced by 3 so remaining signal strength is 20 -3 = 17

if you apply the above formula

17 = 10 * log( signal strength in watt)

Signal strength = 50 watts.

For Question 2 :

ANSWER : Option D, All of the above

For Question 3 :

ANSWER :   Option B , 178 Mbps

C = B * log(1+SNR) Note: Log base 2 not base 10

if you apply the above formula C = 36*log(1+30) = 178 Mbps

Thanks..