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 mild assumptions a hidden Markov chain varies analytically, in a strong sense, as a function of the underlying Markov chain parameters. In particular, we show that, under these assumptions, the entropy rate of a hidden Markov chain is an analytic function of the parameters. We give examples to show how this can fail in some cases. And we… (More)
This paper provides a self-contained exposition of k modulation code design methods based upon the state splitting algorithm. The techniques are applied to the design of several codes of interest in digital data recording.
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 of… (More)