Jimmy K. Omura (born September 8, 1940 in San Jose, California) was an electrical engineer and information theorist.
His notable work includes the design of a number of spread spectrum communications systems, and the Massey-Omura cryptosystem (with James Massey).
Omura and Dave Forney independently realized that the Viterbi decoder was optimal and that it could be applied to intersymbol interference, not just binary convolutional codes as originally described.
According to his friend and colleague Martin Hellman, Omura told him that once you understood dynamic programming, the optimality of Viterbi decoding followed immediately.
He was elected a member of the National Academy of Engineering in 1997 for contributions in spread-spectrum communications and data encryption.