A template-based approach to module generation is presented. This approach allows for the fast and efficient design of layout-rule independent, parametrizable layout generators. By virtue of the use of a true hierarchical compactor combined with a powerful module assembly technique, regular layout structures comparable in density to full custom layout can be generated. The procedural part of this approach has been implemented by creating a C++ object-oriented shell around the trapezoidal corner-stitched data structure of the Tailor layout system. A verification technique has also been implemented which guarantees that generated modules are design rule correct when constructed. Results are given for a ROM and an SRAM matrix generator.>

A method is presented for designing binary channel codes in such a way that both the power spectral density function and its low-order derivatives vanish at zero frequency. The performance of the new codes is compared with that of channel codes designed with a constraint on the unbalance Of the number of transmitted positive and negative pulses. Some remarks are made on the error-correcting capabilities of these codes.

In this paper, we introduce a new approach to design smearing and desmearing filters for data transmission systems to suppress pulse-like disturbances inserted in the communication channel. Our method is based on time domain considerations. It consists of the optimization of two merit factors defined for the impulse response functions of the filters. The first one is a measure of the smearing efficiency, and the second one is a measure of the amount of intersymbol interference caused by the insertion of the two filters in the transmission system. Our method will be applied to smearing and desmearing filters for baseband signals as well as for passband signals. In particular, we show that our method leads to filters having a better smearing efficiency and a simpler implementation than the filters obtained by the classical frequency domain approach.

We discuss[2(p + 1), p + 1]double circulant codes which are the ternary images of the[p + 1,(p + 1)/2]extended quadratic residue codes over GF(9). Herepis a prime of the formp = 12k \pm 5. As a special result we obtain a[64, 32,18]ternary self-dual code which is the largest known code meeting the bound of Mallows and Sloane.

Many modulation systems used in magnetic and optical recording are based on binary run-length-limited codes. We generalize the concept ofdk-limited sequences of length n introduced by Tang and Bald by imposing constraints on the maximum number of consecutive zeros at the beginning and the end of the sequences. It is shown that the encoding and decoding procedures are similar to those of Tang and Bald. The additional constraints allow a more efficient merging of the sequences. We demonstrate two constructions of run-length-limited codes with merging rules of increasing complexity and efficiency and compare them to Tang and Bahl's method.