In fast-moving consumer electronics markets where product lifetimes may be measured in months rather than years, fast time-to-market development of the system-on-chip solutions that lie at the heart of these products has become critical to commercial success. New semiconductor process technologies have the potential to integrate ever greater functional complexity onto realistically priced silicon chips. Yet there still remains a significant design gap between what can theoretically be integrated onto silicon and what can be efficiently designed onto it. In addition, the advent of sub-100-nm process technologies has seen an end to the speed and power consumption scaling that the industry has been used to. This paper examines the current state of the art in SoC technology and identifies some of the challenges that lie ahead if the relentless progress of Moore's Law is to continue fuelling ever more advanced and affordable consumer electronics products. It also looks at the system-in-package solutions that are increasingly being used to achieve levels of functional integration that Moore's Law on its own cannot provide.

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.

This contribution addresses the implications of Heisenberg's uncertainty relation on time-frequency energy distribution functions depending bilinearly on the signal. It is indicated that all these distribution functions must have a certain minimum spread in the time-frequency plane. Further-more such distribution functions can either have correct marginal distributions or be positive, but not both. Therefore a local interpretation of these energy distributions must be taken with care. Some facts determining the choice of an appropriate distribution function will be discussed. A comparison will be made between the spectrogram and the Wigner distribution.

In this paper a digital transmission unit for the forthcoming integrated services digital network (ISDN) is considered. Basic elements of such a unit are an adaptive echo canceller (EC) and an adaptive decision feedback equalizer (DFE). Each of these filters can be realized by a transversal filter structure or by a lookup table structure. An analysis and comparison of the behavior of these two structures is given, The combination of an EC and a DFE can also be realized by a single lookup table. It is shown that irrespective of the particular realization three different convergence phases can be distinguished, and that the overall convergence time is considerably longer then would be expected from the usual simple theory that ignores error propagation in the DFE. Two variants of a hardware realization of such a digital transmission unit are presented. They provide 144 kbit/s full-duplex transmission on the symmetrical cables of the existing local telephone network. A small transmission bandwidth is obtained by applying NRZ signaling. In the first circuit the EC and DFE are implemented by individual lookup tables, while in the second a combined table is used. Both circuits are to a large extent, implemented digitally. Due to the relatively low sampling frequency and the acceptably low power consumption they are very well suited for large scale integration with present day technology.

In this paper we present some tools that can be helpful in the design of adaptive digital filters operating with the so-called sign algorithm. Although theoretical results with respect to the convergence behavior of such filters are available, it may be hard to derive practical design criteria from them. We introduce a new type of design graph, which characterizes the convergence pretty well and which we call "the elephant's ear," due to its typical shape. We also consider some effects of non-Gaussian statistics of the received signal and show how the preceding analysis can be extended to include the effects of dithering. Finally, we pay attention to the digital word lengths required in a finite precision implementation. The subject of this paper is restricted to adaptive digital echo cancellers (EC), but the results can be generalized to include other adaptive filters like decision feedback equalizers (DFE) or combinations of EC and DFE.

The convergence of an adaptive echo canceller operating with the stochastic iteration algorithm in the presence of pseudo-noise data signals has been analyzed. This convergence can deviate appreciably from that with "random" data. An approximate expression for the convergence characteristic has been derived and verified by computer simulations.

Continued investigations on the harmonic-sieve pitch extractor have led to several major improvements, such as e.g. even less frequent occurrence of pitch errors, especially for speech with low pitch, and extreme robustness with respect to low-frequency cut-off in the input speech. Additionally, a voiced-unvoiced detector is presented which is based on tracking of spectral intensity variations of subsequent speech segments. It can be incorporated in the pitch extractor with very little overhead.

The Wigner distribution is a signal transformation that exhibits some very interesting properties with regard to time-frequency signal analysis. The most important of these properties are discussed. The Wigner distribution is then compared with other time-frequency signal representations, such as the spectrogram. It appears that the Wigner distribution is better able to display non-stationarities in the signals.

A method that was recently developed for describing linear time-varying digital systems in the frequency domain will be applied to decimators and interpolators. This method allows a generalization of transposition to these time-varying operations, giving both a structural and a functional relationship between a digital system and its transpose. It is shown that decimation and interpolation are related by transposition, and the consequences of this interconnection are discussed.

A digital circuit suitable for detection of tones in signaling applications is described. The amount of hardware required for the realization of the circuit is shown to be quite small. The circuit may be used for both analog and digital input signals. For analog signals, the necessary A/D conversion becomes very simple. Results of simulations on a digital computer are given that indicate the good performance of the circuit.