Deck 10: Channel Coding

Question 1

An IR remote control sends a 25-bit sequence every 0.01 s.The data rate of this remote control
equals _______ bps.

Answer 1

Question 2

Consider the binary data packet shown as a spreadsheet with columns indicated by letters and
rows by numbers.The parity bits are in column E.The code words use _____ parity and the LRC
uses _____ parity.

Answer 2

Even, odd.Each row contains an even number of 1's, and the LRC makes each data column
contain an odd number of 1's.The LRC code word also has even parity.

Question 3

An error-correction scheme appends a parity bit to each data byte to form code word and the
sequence of 15 code words is followed by a longitudinal redundancy check (LRC) code word to
form a data packet.The resulting DIF = ____ .

Answer 3

1.2.Each code word contains 9 bits of which 8 bits are data.Each data packet contains 16
code words of which 15 contain data.

Question 4

The channel from a space probe to earth has a bandwidth Hz.The channel capacity when
the probe is km from earth is bps = 10 Mbps.Using the inverse square law to describe
the signal power loss, the capacity when the probe is at km from earth equals _____
Mbps.Assume that the noise power is constant.

Question 5

The SNR of the channel from a space probe to earth equals 2047 and the channel capacity C = 5 x bps.The channel bandwidth = _________ (x.xx) MHz.

Question 6

Consider the binary data packet shown as a spreadsheet with columns indicated by letters and
rows by numbers.The last row contains the LRC and there is one error.The letter-number
address of the error is___.

Question 7

Adding a parity bit to a data byte results in a

Question 8

A movie source generates a set of 1080p HD digital image files, each file composed of 1920 x
1080 picture elements (pixels), with each pixel specified with three bytes of information.When
the source produces 30 images per second, its raw (uncoded) data rate equals _____ bps.

Question 9

The data rate produced by a typist is 56 bits/second.Assuming that the text is encoded using the
standard 8-bit ASCII code, the number of letters that is typed in one second equals ____
letters/second.

Question 10

The threshold intensity for a receiver If the intensity produced by an antenna
equals at a range of 1 m, the maximum reliable range of the system equals ____ km.

Question 11

The channel from a space probe to earth has a bandwidth Hz and a channel capacity C = .The signal-to-noise ratio equals ______.