December 1995, Volume 4, Number 4
The article deals with assembling and application of a complex sequential circuit VHDL (VHSIC (Very High-Speed Integrated Circuit) Hardware Description Language) model. The circuit model is a core of a cryptographic device for the signal encoding and decoding of discreet transmissions by TV-cable net. The cryptographic algorithm is changable according to the user's wishes. The principles of creation and example implementations are presented in the article. The behavioural model is used to minimize mistakes in the ASICs (Application Specific Integrated Circuits). The circuit implementation uses the FPGA (Field Programmable Gate Array) technology. The diagnostics of the circuit is based on remote testing by the IEEE Std 1149.1-1990. The VHDL model of diagnostic subsystem is created as an orthogonal model in relation to the cryptographic circuit VHDL model.
Signal of the DCF amplitude-modulated transmitter, located in Braunschweig (Germany) is widely used for synchronizing of time information during different laboratory and field experiments. The full time information of this time normal is coded and presented within every minute using different length of second time marks. The knowledge of the exact time of occurrence of seismic events is the fundamental information during the seismic activity monitoring. With respect to the fact that the duration of individual records having sometimes a few seconds at minimum, the time generator ensuring the complete time information within every second, is needed. That is why the special timing device controlled by the DCF77 signal and generating every second the full time information was developed. Description of the function of decoder, internal clock and fast code generator implemented on the basis of FPGA circuits is the subject of this paper.
A method of testing triples consisting of samples of three independent groups such that no two samples of the same group are tested at the same time, no sample is tested with another one more than once and after each test one sample of the triple is included in the following triple is presented.
To approximate the real characteristic functions of the non-linear electronic elements various mathematical methods are used. Such methods offer the analytic approximating mathematical expressions as their results. One of the interesting non-conventional method for the approximation task is the approach of the fuzzy sets theory and fuzzy multivalue linquistic logic. To apply of this method we obtain the approximation functions of the non-linear fuzzy rule based form. To design of such fuzzy model we use the approaches of the fuzzy non-linear regression analysis. The article describes the structural and parameters identification of such model and introduces the results of the numerical experiments.
The present approach to the diffractive element design is based on Kirchhoff scalar theory of diffraction. Predictions made by this theory become unreliable if the diffraction of polarized light is evaluated. The paper presents the vector correction of Huygens-Fresnel principle and suggests a method for fast evaluation of rapidly oscillating integrals.