13 encoded codewords. (C2) The codewords at addresses a and a + 2 8 should have diierent parities (of number of 1's). We use the following heuristic procedure to reorder the table so that these two conditions are satissed. Denote by x; y) a contiguous table portion that starts at address x and ends at address y?1 (inclusive). Starting with s = 000, we look… (More)
This article is a summary of the plenary lecture that I gave at the 1995 IEEE International Symposium on Information Theory. The lecture was intended to give a concrete and elementary introduction to the subject of symbolic dynamics. From my point of view, symbolic dynamics is the subject of \coding" from one \constrained set" of sequences to another. Of… (More)
—We develop methods for analyzing and constructing combined modulation/error-correctiong codes (ECC codes), in particular codes that employ some form of reversed concatenation and whose ECC decoding scheme requires easy access to soft information (e.g., turbo codes, low-density parity-check (LDPC) codes or parity codes). We expand on earlier work of Immink… (More)
We prove that under a mild positivity assumption the entropy rate of a hidden Markov chain varies analytically as a function of the underlying Markov chain parameters. We give examples to show how this can fail in some cases. And we study two natural special classes of hidden Markov chains in more detail: binary hidden Markov chains with an unambiguous… (More)
We describe a digital holographic storage system for the study of noise sources and the evaluation of modulation and error-correction codes. A precision zoom lens and Fourier transform optics provide pixel-to-pixel matching between any input spatial light modulator and output CCD array over magnifications from 0.8 to 3. Holograms are angle multiplexed in… (More)
We study the classical problem of noisy constrained capacity in the case of the binary symmetric channel (BSC), namely, the capacity of a BSC whose inputs are sequences chosen from a constrained set. Motivated by a result of Ordentlich and Weissman [In Proceedings of IEEE Information Theory Workshop (2004) 117–122], we derive an asymptotic formula (when the… (More)
—In digital storage systems where the input to the noisy channel is required to satisfy a modulation constraint, the constrained code and error-control code (ECC) are typically designed and decoded independently. The achievable rate for this situation is evaluated as the rate of average intersection of the constraint and the ECC. The gap from the capacity… (More)
In this paper, we generalize a result in  and derive an asymptotic formula for the entropy rate of a hidden Markov chain, observed when a Markov chain passes through a binary symmetric channel. And we prove an asymptotic formula for the capacity of a binary symmetric channel with input process supported on an irreducible finite type constraint.