March 1994, Volume 3, Number 1
An analysis of the phase and amplitude fluctuations in oscillators with simple resonant circuit is presented. Negative feedback is used to minimize effect of the inherent noise produced by bipolar transistor on fluctuation characteristics.
In the contribution the basic principles of the Functional Stability Theory are described, some problems discussed in more details, the Criterion of the Theory is shown, possibilities in Synergetics are mentioned and an example of the Theory application is introduced to show the effectiveness of the approach.
Present paper deals with the problem of automatic design of the implicit state model (in its decomposed parametric form) of any one-dimensional piecewise-linear (PWL) system. This model consists of the internal and the external parts which provides the possibility to find the model parameters, i.e. to solve separately the two main problems of an one-dimensional PWL model design:
(i) existence of the individual breakpoints of the resultant PWL characteristic (determined by the internal block);
(ii) setting of the breakpoint co-ordinates (determined by the external block).
The lattice structures for linear prediction were formulated in speech processing by Makhoul . The LPC coders are often used in the transmission of speech signals. Such systems include a filter in the receiver that produces an approximation of a speech waveform. The parameters of this filter are extracted from the speech signal in the vocoder for frames of N samples. The lattice all-pole structure -with two multipliers frequently occurs in such vocoders. The signal flow graphs (SFG) are very useful for a computation of the transfer function from the source nodes to the sink nodes.
An efficient method of time domain analysis of linear systems is proposed. This method is based on the state space approach and on the numerical Laplace inversion. The problems of the sampled-data input signal and steady-state response computation are discussed.
The last decade has seen unprecedented developments in land mobile communications in Europe. The introduction of analogue cellular networks in the early 1980 's started a revolution in technologies and services which, even today, continues to gather pace. As mobile communications looks set to become a mass market, the range of options available to customers has never been greater. This paper briefly reviews each of the main systems which are, or are soon to be, available and discusses the key issues which will determine their success.