CMPT 165: Review

Bits

Interference from natural phenomena, distortion from electrical or magnetic interference can cause damage or loss of data.

**A parity bit** is an extra bit added to a code before transmission
to help the hardware detect errors. It is set to

- 1: if a sequence has an
*odd*number of 1 bits - 0: if a sequence has an
*even*number of 1 bits.

**Checksum** is a technique for detecting damaged bits.
The software sends the sum of the numbers in the
message. If a message consists of the numbers

1, 3, 5

the software sends

1, 3, 5, 9

When the messages arrives, the receiving software sums all the values except the last, and then checks to ensure the sum equals the last value.

Modulation

CMPT 165: Review

Bits

``CMPT 165: Review'' by Tamara Smyth, Computing Science, Simon Fraser University.

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Copyright ©

Please email errata, comments, and suggestions to Tamara Smyth<tamaras@cs.sfu.ca>

School of Computing Science, Simon Fraser University