- Submitted By: nsemjack73
- Date Submitted: 09/10/2015 1:16 PM
- Category: Technology
- Words: 347
- Page: 2

2-10 Define frequency Spectrum and bandwidth

Frequency spectrum is the wide range of frequencies found in the Frequency domain.

Bandwidth is the specific start and stop of the allowable frequency range.

2-11 Define electrical noise

Any undesirable electrical energy that falls within the pass band of a signal.

2-12 give a brief description of the following forms of electrical noise; man-made, thermal, correlated and impulse

Man-made: noise that is produced by device.

Thermal: is the rapid and random movement of electrons agitating and is present in all electronic components and communications systems.

Correlated: noise that is mutually to the signal and must not be present in a circuit.

Impulse - are high-amplitude peaks of short duration in the total noise spectrum.

2-16 Brief describe the significant of the Shannon limit for information capacity.

Shannon limit indicates that the higher the signal to noise the better the BER.

2-17 What is meant by the M-ary encoding?

M-ary comes from the term "binary", but M represents a digit concerning the number of conditions, levels, or combinations possible for a given number of binary variables.

problem chap2

Problems Chap 2

2-10

using shannon-hartley theorem

signal to noise ratio, SNR = 20 dB or 10000

that is , S/N = 10000

Bandwidth, B = 100 kHz

C = B*log(1 + S/N) [log is taken in base 2]

C = 100*log(1+10000) kbps

C = 1328785.66 bps

2-11

If by number of conditions it means the number of different combinations then,

for n bits,

number of different conditions = 2^n

for exaple for n = 2 , (00,01,10,11) that is total 2^2 = 4

using this

a. = 2^3 = 8

b. = 2^5 = 32

c. = 2^7 = 128

d. = 2^12 = 4096

2-12

M - number of different levels in signal

M = 2^no. of bits = 2^4

B - bandwidth

B = 10000 Hz

highest bit rate possible = 2*B*log(M) [log is in base 2]

highest bit rate possible = 2*10000*log(2^4) bps

highest bit rate possible = 80000 bps

2-16...