Vol.11, No.1 (1998) 71-85
AbstractA line coding scheme based on trellis shaping is presented. The trellis shaping algorithm is used to obtain a signal with a controlled running digital sum as well as to achieve a Gaussian-like amplitude density distribution. The former causes a first order spectral null at zero frequency, while the latter allows to preserve a significant part of the gain attained by pure trellis shaping. Spectral nulls at arbitrary frequencies as well as second order nulls can easily be realized. The complexity of a slightly modified four state Viterbi algorithm is sufficient to achieve the major part of the possible gain.
Key words: Trellis shaping, Viterbi algorithm, discrete time sequence, power spectral density.