New method of simultaneous transmision any type of measurement sensors signals in the four channel transmultiplexer structure

Abstract

The signal trasmultiplexation system implemented to simultaneous digital data transmission from measurement sensors is presented in the paper. In general, those can be data from any type of sensor generating digital data on location, force, acceleration, pressure, etc. The issue dealt with in the paper is important as devices manufactured at present contain ever-growing number of sensors. Increasing the volume of sensor wiring is a non-optimal solution. Instead, multiplexers are used, which alternately place elements of successive signal samples in successive time slots. The proposed solution based on the use of transmultiplexers involves combining measurement signal samples into one signal that is transmitted over a single path. If properly designed, FIR type filters make it possible to obtain the signal that is scattered both in time and frequency domains. Coefficients of filter banks of the order I=16 were determined numerically with the accuracy Qmin= 2,962.10-6 for 4-input system. Frequency characteristics of filters are shown in Fig. 3. The characteristics do not resemble those of known filters (low pass, high pass) as they are distributed in the same frequency band. If properly designed, they make it possible to almost ideally reconstruct measurement signals from a complex signal. The latter combines all independent input signals thus making one entity. Each sample of the complex signal contains a fragment of the information of all input signals. It is preliminarily encoded and thus resistant to individual transmission errors. The filter order is virtually arbitrary, with the restriction that it should at least be equal to the number of input signals. It was noted that for real measurement signals, transmultiplexation in which filter coefficients were determined numerically and rounded to 4 significant places turned out to be sufficient.