Popular Convolutional Codes
An especially popular Viterbi-decoded convolutional code, used at least since the Voyager program has a constraint length k of 7 and a rate r of 1/2.
- Longer constraint lengths produce more powerful codes, but the complexity of the Viterbi algorithm increases exponentially with constraint lengths, limiting these more powerful codes to deep space missions where the extra performance is easily worth the increased decoder complexity.
- Mars Pathfinder, Mars Exploration Rover and the Cassini probe to Saturn use a k of 15 and a rate of 1/6; this code performs about 2 dB better than the simpler k=7 code at a cost of 256× in decoding complexity (compared to Voyager mission codes).
Read more about this topic: Convolutional Code
Famous quotes containing the words popular and/or codes:
“That popular fable of the sot who was picked up dead-drunk in the street, carried to the duke’s house, washed and dressed and laid in the duke’s bed, and, on his waking, treated with all obsequious ceremony like the duke, and assured that he had been insane, owes its popularity to the fact that it symbolizes so well the state of man, who is in the world a sort of sot, but now and then wakes up, exercises his reason and finds himself a true prince.”
—Ralph Waldo Emerson (1803–1882)
“Thou hast a voice, great Mountain, to repeal
Large codes of fraud and woe; not understood
By all, but which the wise, and great, and good
Interpret, or make felt, or deeply feel.”
—Percy Bysshe Shelley (1792–1822)